Boeing 727 Falls From the Sky TWA 841
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- Опубликовано: 17 май 2024
- Could 727 pilots really get more capability from the airplane by "tricking" the flap system? Did that lead to the TWA 841 incident. I'll tackle these two topics in this video.
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Note, the maximum mach limit in the 727 was either .90 or .88 depending on the exact model. That's the upper speed limit when at altitude. At low altitudes the plane is limited by indicated airspeed, not by the mach number. This is because the speed of sound decreases with a drop in temperature, and indicated airspeed decreases with altitude for a given true airspeed. Thus at high altitude, you can be way below the IAS limit, but creeping up on the mach limit as the speed of sound decreases. 
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Greg, sometimes in your videos I will hear you make references to build quality. What makes an aircraft well-built or poorly built? I think this would be a great video idea. Love your work, keep it up.
Pan Am 727. I don't remember the model. It was my second or third jump seat trip, and in another couple of years they'd be gone. It has TWO jump seats, plus a crew of three. Which I appreciated because as a trainee controller I would get bumped by any airline employee or higher seniority controller. It was a little cramped, but not as bad as some aircraft like the the DC9-10 if memory serves me correctly
The B727 and L1011 were both elegant airplanes. Got to fly jumpseat on a Delta L1011 before they retired them. Another "over engineered" ( -cough- survivable if you're not too unlucky) elegant machine.
wait, you're not a disembodied voice talking over a slideshow? I'm not sure I can handle this.
All channels are AI until I see a face
Funny how you build up a picture of someone from their voice and when you see them, they're totally different !
you haven't seen wright brothers videos.
Greg has appeared in a few videos before 😂
btw no offence meant :D I realize that especially if you want to knock out a quick one, its easier to just record yourself instead of sitting down, making a slideshow, probably writing a script, recording that and so on and so forth. Its just an unexpected departure from your usual MO.
I had Hoot Gibson, TWA Captain, on my jumpseat at Eastern Airlines some years after the incident. He claimed that what saved his employment was the fact that the #7 slat actuator was ""misplaced" during the investigation and neither Boeing, the FAA or the NTSB could dis-prove his theory of the slat actuator malfunction.
Doesn't everyone love agreed upon lies!
The slat actuator was sent o Being for inspection. Boeing told the NTSB “We inspected it and there wasn’t anything wrong with it.” The NTSB asked Boeing to give it to them to inspect to which Boeing said “Oh, we threw it away, sorry.” Given the latest way Boeing is acting about giving up information it looks like Hoot wasn’t being deceptive. Interesting to note that not one of the crew members changed their stories, even the FE who was promised amnesty quit and went to work as a teacher.
Back in the eighties I worked with a project manager who had flown KC-135's in the Air Force. He told me about the standard response after an incident: "While that was hairy, but we got the the crate back on the ground, now let's get our stories straight".@@The_New_IKB
I had Hoot on one of my flights, too. Although, I did not ask him about anything. I was a TWA 1989 hire riding side saddle on the B727. I was never sure of what was true or what was apocryphal about this incident. 4,000 hours of combined FE and then FO time has left a constant reminder by the continual ringing in my ears. Well loved jet, it also went by the name within the company as "Jurassic Jet", or "Miss Piggy" because of slow climb and the massive descent rates you could get out of it (climbs like a pig, descends like a pig). "Clacker cruise" on the over-speed warning audio alert was not unheard of. Edit - a remark that I frequently heard at work was that Hoot stood behind his story. That is not any sort of proof, I acknowledge. I did not like being at FL 390 or above that much in that airplane. The aircraft handling felt like trying to stand on a bowling ball, keep working yaw dampers, please.
If flying at FL 390 was possible via a 'trick', what was the point of being there at all? And wouldn't smart air controllers be aware that was unusual for the 727's flight envelope?
When I was a 130 FE, there some pilots I didn't like leaving unsupervised in the flight deck. If I had to pee I did it quick and got right back upstairs to check my panel and make sure nobody had touched my stuff.
I understand. I hated when the Capt would come back and touch stuff. It usually resulted in a pack trip or duct overheat.
The subject 727 was ferried to the TWA overhaul base in Kansas City and rebuilt. A friend of mine was one of the leads on the rebuild. It eventually ended up with Amerijet I believe. Amazingly tough airframe. I didn't start flying 727's till 1983 so the TWA incident was still pretty fresh and talked about in training depts. I never saw the unauthorized procedure done or would I have ever done it myself. I have however been a bad boy and extended the flaps to 40 on a blocked out gate occasionally, operational necessity of course. That was easy to do. Racking my old brain on 727 system knowledge is bringing back a few memories. Keep the 727 stuff coming Greg. Thanks for the video.
Amerijet? Oh no. I worked for Amerijet while laid off from EAL (1988). We MX guys called the place "Happy Jet" - but there was nothing "happy" about working for that outfit. I could tell you some stories - you simply would not believe. The crap the management of that place would try to get away with was beyond the pale. They are damned lucky their operation was not permanently shut down by the FAA.
Thanks Greg. You make a dumb flight sim player like me feel like I'm getting a graduate level education. I sincerely appreciate your work and how effective it is at helping us understand this all.
Thanks. It's a skill to talk that naturally and concise on a subject as complex. I can't see a script either.
Thanks, there was no script, I was shooting from the hip on this one. I made it quickly and Dee filmed it for me as I used here office at Eurocompulsion. It's not my normal format, but a lot of people asked about this and I wanted to get the answer out there quickly.
Circuit breakers were used to "trick" the system in Phantoms too. There were interlocks in the missile firing system to prevent the forward Sparrows from being selectable when the center line fuel tank was installed. This was because the forward fins of the missile would hit the tank when the missile was ejected. There was also an interlock that prevented the Sidewinder's motor from firing if the speed brake was open as the speed brake was directly behind the missiles.
When training with simulated Sparrows (just a little electronics package that was attached to the missile umbilical to allow the system to think there was a missile there) and with captive carry Sidewinders they'd pull those circuit breakers to be able to select the forward Sparrows and to "launch" a Sidewinder with the speed brakes out.
I never personally saw a jet come back with holes burned through its speed brakes, but I did talk to people who had.
There was also a motor fire circuit breaker that we pulled when loading and testing Sparrows on the ground. If the RIO didn't reset that before they tried to shoot the missile, they just had an expensive dumb bomb. I have personally seen that happen.
One of the weirdest things about this story is that there are two Hoot Gibsons that are pilots.
And one is a space shuttle pilot while the other one almost wrecked his 727, so it's like they are opposites.
They should go to Hooters together,
at least once...
and share a picture for posterity 😅
@@RCAvhstape Nope, they are both heroes. What most likely happened on TWA 841 is that the right outboard aileron fluttered due to a fractured bolt that caused the 727 to turn off its heading. With the plane turning right and the autopilot commanding a left turn to get back onto its preset heading it put the plane in a cross controlled situation. The lower rudder yaw damper sensed discrepant rudder inputs that resulted in a lower rudder hardover. With the flaps retreated the outboard ailerons lock out and rudder movement via the rudder pedals is limited to prevent over controlling so with a lower rudder hardover and a fluttering outboard aileron there was nothing the pilots could do to prevent the 727 from going into a dive. When the landing gear was extended the right gear overextended that caused a loss of hydraulic pressure to System A hydraulics which powers the lower rudder, flaps and slats. With hydraulic pressure gone the lower rudder centered and allowed the pilots to recover. The No.7 slat extended due to the loss of hydraulic pressure and the aerodynamic forces of the dice. Analysis showed that it didn’t lock into its locking mechanism while the other slats did and was kept retracted by hydraulic pressure and aerodynamic forces alone. It had nothing to do with the upset and extended because of the upset.
1:22 The fact that they could extend the landing gear at that speed is more than impressive.
Yes, and still land on it!
Overspeed the gear and live? No brainer...
727 landihg gear was hell for stout
The fragile part is the gear doors. I bet some of those, if not all of them were lost.
I heard in A&P school that the gear moved back 2 inches during this event. They didn’t say where that was measured from but if it’s true it seems like a lot of stress happened there.
Hi Greg, I was a TWA mechanic at the overhaul base at MCI in the 80's-90's. Before that I was an MO ANG Crew Chief at Rosecrans ANG Base in St. Joseph, MO. In the 70's. Many of our ANG pilots were also TWA pilots and TWA did training off our runway. They would do touch and go's there in the 707's. I knew a lot of them personally. There's an alternate story that also corrobates with one of our TWA maintenance instructors who was an ex Boeing engineer.
The other reason pilots did this was for fuel economy. Remember, there was 2 oil crisis's in the 70's. Airlines were handing out bonuses to aircrews who could save fuel. Doing the 2 degree flap trick also lowers the nose on the 27 in cruise flight. Miss Piggy (pilots name for the 27 because it didn't climb well above FL 320) flys a few degrees nose high making it a little aerodynamically dirty. 2 degrees back on the flaps dropped the nose and really improves fuel performance allowing them to throttle back a little. This is per the pilots I knew and my TWA maintenance instructor (who was privy to this information). Sooo, whether it was so they wanted to go higher or save fuel for the bonus is up for debate. The story we had at the overhaul base was the fuel savings bonus. The Story about the FE engaging the CB is correct. Hoot popped the CB's and didn't tell the FE assuming he was "in the know". As you may know, CRM wasn't implemented until years later. BTW, I worked on N840TW (Dive Bomber) many times. When the light was right, there was a slight rippling along the fuselage above the wing roots. We also took some safety wire and stretched it from a point at the radome edge to the edge of the nav lights. Compared it to another "shorty" 727. The length was a little longer than any of the others. The old 27 was one of the toughest birds ever built. Also BTW, they stopped handing out fuel bonuses right after this. Coincidence? Anyway, thought you might want to know this little factoid from someone who was there. On a personal note, TWA was one of the finest airlines (if not also one of the most troubled) I ever worked for. We could do heavy maintenance that normally only Boeing was allowed to do. Amazing knowledge at that overhaul base. We were like family. I was there for the final years. Carl Icahn is the scum of the Earth and the sole reason I never got to retire there.
Thanks for all of that. Everything you said makes perfect sense to me.
Thank you Sir!
Great story Mark. I worked at JFK, never met Hoot, but sure would have loved to. I'm still intrigued by this story even to this day. I remember the incident very well as a kid growing up in the Bronx. Little did I know that I would be working for TWA at JFK where 841 originated. Hoot seemed like a nice guy, and a great pilot, but I've always believed that he had to have something to do with the upset of the aircraft.
BTW, I can't agree with you more about Icahn. He destroyed our airline, and I also hold him accountable for the loss of flight 800. My friend Elsie, who I worked with at JFK, was non-reving on 800 that night, along with her 9 year old daughter. I'll never forget her.
Back when I flew C-130's, we did the same thing. Much simpler flap system, but cracking about 5 - 10 % flaps in the climb gave it just a little increase in rate of climb. Useful when we were heavy and needed to get higher quicker. Luckily I started flying in a time when there were still a lot of old crusty Viet Nam vets still on active duty. They passed along so many little tricks that only worked if you really understood your aircraft systems.
Yes, we were still doing that in the 130 during my last deployment to Iraq in 2008. Put in about 10% flaps if we needed to loiter at high altitude and stretch the fuel.
I was a check airman and flight engineer examiner on the 727 at TWA. Most of us in house believed Hoot’s version of the story. Knowing the high level of professionalism of all those involved, we doubted that they chose to intentionally pull circuit breakers to go higher. Many at the airline believed Hoot was a hero. I never met Hoot so am going by my peer’s impressions. Man than was a long time ago.
While I suspect you are right about what caused the TWA 841 to fall out of the sky, I need to point out some additional testimony that came out 11 years after the incident (Quoting from a Chicago Tribune article that came out October 14, 1990):
Last week the Air Line Pilots Association, citing new evidence, petitioned the five-member safety board to rescind its 1981 ruling and conclude that the flight`s spiral dive, one of the most unusual events in commercial aviation history, was caused by a mechanical malfunction.
According to an affidavit filed with the petition, the same plane that Gibson flew on Flight 841, N840TW, was used in 1977 on a TWA test flight. During the test flight, the affidavit says, the pilot (* encountered serious problems controlling the aircraft-problems that were similar to what Gibson encountered two years later on Flight 841 before the plane went into its dive. Despite the lengthy safety board investigation and nearly 20 civil suits filed by Flight 841 passengers, information about the test flight was never disclosed by TWA, according to John Rohlfing, a TWA pilot and chairman of the union`s TWA accident investigation committee.
The affidavit was signed by P.T. Williams, who has been a TWA pilot for 31 years. According to the affidavit, Williams flew plane N840TW on a test flight May 23, 1977. On board were several supervisors.
During the flight, Williams states, he was told to forcibly override the autopilot so personnel on board could evaluate the response. The procedure worked the first time; but on the second attempt, the autopilot gave the appearance of having disconnected while actually remaining engaged. Subsequently, Williams said, ”the flight controls became extremely difficult to manipulate” and the plane became difficult to fly. After ”much effort,” the affidavit continues, he was able to return the plane to Kansas City.
Rohlfing said TWA never notified pilots of the occurrence. Williams himself only remembered the incident a few months ago, Rohlfing said, after another TWA jet encountered similar control problems in midflight and was forced to make an emergency landing in Dayton.
Williams is a member of the union`s TWA accident investigation committee. In studying the Dayton incident, said Rohlfing, Williams remembered the 1977 flight, went back to his log book and discovered it was the same plane Gibson flew in 1979.
I spent 9 years on the 727 and I remember that story exactly as you portrayed it! Great systems review too! Thanks
Thanks Joe.
Starting as a young kid, I was a passenger on 727s during maybe 30-40 individual flights from the 1970s into the early 1980s. Being based in St. Louis, in my young mind a TWA Boeing 727 _was_ a commercial airliner. It was the Greyhound bus of the sky.
Early in my flying career, so to speak, I can remember trying to size-up just how scared I should be of this amazing activity. Since flying always involves a lot of sitting around, I had ample time to study the parts of those planes a passenger could see. A thin veneer of civility covered a distinct impression of being 'all business', underneath. It was obvious that many of them were very well-used, and were rapidly racking up more and more flight hours, yet they endured and everything always seemed to work reliably. Before long, I came to trust them to get me back and forth safely.
The flaps really were incredible to watch (and listen to). I knew from their use that they had to be increasing lift at lower speeds, but I was damned if I could see how they did that. It all looked like such an aerodynamically dirty mess when everything was deployed! Also, the engines certainly _were_ loud, and you certainly _didn't_ want to live near an airport in those days.
As someone with very limited aircraft knowledge, I appreciate that you explained everything in a manner I can understand. Thanks for the interesting video.
Loved flying on the 727. Well, IN the 727. As a passenger, maybe 20 times or so in my life. I always picked a window seat toward the rear where I could watch the flaps. Highlight of the flight was take off and landing of course, but the flaps were where it's at. You could see the screws turning as they adjusted, and the internal structure of the wings became fairly clear. Remarkably, they held together through all this almost as if they were designed that way. Nothing but fun. Thanks Greg.
I told this same anecdote myself on another channel! It was the best seat in the cabin, especially for a young pilot.
The 737 of that vintage was not nearly as interesting, but I did enjoy sitting behind the wing in those as well, to watch the thrust reverser buckets come out and (feel) the visceral roar they made.
Yep. And loved the flaps "motor" noise as they were being extended or retracted.
If memory serves, the displaced slat in cruise caused an opposite direction of roll to what would happen with the #7 slat stuck in its deployed position.
I read Stan Stewart's chapter on this in one of his books, I am absolutely sure that Hoot Gibson and his crew were blameless. They tried to claim that the crew had deliberately over recorded the CVR, but of course they could not have done that due to the broken gear squat switches.
I like that robust shade/pattern of plaid Greg. Thanks for the content! 🐿
It was unintentional, I closed a door that was too my left to cut down on the shop noise. That caused the shadow.
New Yankee greg ;-)
My old man was a good friend of Hoot. They were both TWA Newhires, both on the airplane at the time, and had flown it many years as FO and CA. Dad reported that Hoot said to him they didn't do it and the company threatened the FE to go with that line or lose his job. His position was that when up against the company, the manufacturer and the government, you're going to cave. Hoot never did and retired from TWA long after the incident. The FE resigned very early.
When I got hired at TWA dad told me to remember that whatever you do, just go to the office and tell them what you actually did and most of the time they'll back you. If they don't, well you're better off leaving anyway.
I flew the 727 about 5 years as FO. Many, many years had gone by since Hoot's incident but a few things stick with me. First is that the chart holder on the yokes had a pretty weak spring holding the clamp, and when you snapped it the autopilot would disconnect. A captain told me it was because of the TWA 841 incident because when the airplane got into the dive the autopilot wouldn't disconnect. He said the crew might've put the gear down to slow down, but it is the reason the autopilot disconnected because the retract cylinders went over center and pulled the rams out of them evacuating both hydraulic systems this disconnecting the autopilot and allowing Hoot to regain control.
I flew with a captain that told me that Hoot and the crew did do the American Airlines West Coast Cruise technique, as it was called because AA was the originator, and I told him dad had told me they didn't. That captain had bought a 727 sim from the company and ran a school well known in SoCal, it seemed to me he had more to gain from it being that way than dad did... he wasn't in business.
Hoot had a long reputation, known for stunts and accidents outside the airline, and was in the office many times, but I never got the idea he would've lied to dad. Like so many airplane stories, the truth is hard to know and sometimes is between the lines.
Company, manufacturer, govenment... remember even when you are flying SOP to CYA.
B727 MXr here (23 years). I saw this result coming from a mile away. Poor Cockpit communication ("resource management") nearly cost the aircraft and all souls aboard. Their Guardian Angels were working OT that day for sure.
One circuit breaker collar would have prevented the whole incident. Think about that for a minute. The FE would return to his seat and either not see the white band of a pulled or tripped breaker, or question someone about why there was a breaker collared that hadn't previously been. There is an entire bag of collars in the spare bulb kit, and usually a couple stuck to some 1864 lambs. Thank goodness they saved the aircraft. The 727 was a tank, as Joe Patroni would say.
@@dougrobinson8602 Believe it or not - "Joe Petroni" (actor George Kennedy) was my inspiration to become an A&P ... Well, in truth, my Dad moreso - as he was always bringing me and my siblings to the local airport to watch aircraft operations.
What was the motivation for this? Why would pilots care about the increasing the max altitude?
@@MikeF1189 More altitude = less dense air = less resistance (drag) = more speed or efficiency
@@MikeF1189. Speed. Every pilot wants to get there faster. It is a really dumb thing to do for the reward.
Excellent summary for those of us who know the technical aspects and for those that don’t!
The pilot on the plane just became an unintentional test pilot taking everyone else along for the ride.
I think you're right about what happened. I can't see them erasing the voice recorder by habit when they knew there would be an investigation. Their version of the story sounds too much like one of those "I was just driving and ________ happened." stories.
Except what explains the 9+ minutes that were found on the CVR which the investigation conveniently left out because it didn't adhere to their (the NTSB) theories?
@@raymarshall6721 That would be the ~9 minutes conveniently provided as a full transcript in Appendix D of the NTSB Accident Report, would it ? It only consists of lightweight cockpit chat + some ground controller comms *back on the ground* in Detroit, so it's not very interesting - or mysterious. The other ~20mins was reported as blank.
@@raymarshall6721I didn't know about that, but that seems to further indicate that the erasure(assuming that's what it was) was not done out of habit. If it was a habitual response to erase the CVR, why would they only erase a portion of it?
@@GlimmerOG And HOW could they erase just a portion of the tape if, as the Wikipedia article on this crash reports its source to claim, "The CVR tape can be erased by means of the bulk-erase feature on the CVR control panel located in the cockpit." Bulk erase subjects the entire tape to erasure at the same time rather than by running the tape past an erasure head..
Believe me, the 727-200B is one hell of a tough aircraft. We flew out of ORD to MIA to GRU. And 45 minutes we went in to a CB and we dropped so hard that i noticed the right wing was like 5' over the fuselage. The food was flying and people were screaming. I was having the time of my life. Today's planes are allergic to storms! 😂😂😂😂. Not back in the 70's. After earning my licence i took Acro and fell in love!!!
Back in the 'wild west' days of commercial aviation.
Thank you for the time with this video Greg. Lots of in-depth technical information about the Boeing 727. Just some things to mention here:
1. To have only the trailing edge flaps extend requires more than simply pulling the circuit breaker to the Leading Edge slats. You first have to turn the Alternate Flap switch on, pull the circuit breaker, turn the Alternate Flap switch off and then extend the flaps.
2. The NTSB declared that the isolated extension of the No.7 leading edge slat after the extension and retraction of the slats is what caused the upset. With the slat extended it caused the 727 to roll over into a dive until at 8,000 feet it tore off and enabled the pilots to recover the plane.
3. The pilots did NOT erase the CVR. There was still 9 minutes of recording available to the investigators where they were talking to each other and to TWA Ops after they had landed. The dive and the events leading up to it would not have been recorded because from when they recovered the plane until they landed was 42 minutes so the recording would have begun 12 minutes after they recovered from the dive. Hoot Gibson left everything in the cockpit as it was to help the investigators figure out what happened which is inconsistent with one trying to coverup a misdeed they did. For the CVR to be erased, the plane must be on the ground and completely shut down with the brakes set and the damage to the airplane, in particular the landing gear, meant that its computers didn’t recognize it was the ground. Therefore the pilots could not have erased the CVR even if they wanted to. The wiring to the CVR could have been damaged by the 6G pullout or it was defective even before the flight. Another explanation for the erasure was that a CVR expert determined it was due to the slow transfer of power from engine power to APU power after the engines had completely shutdown after landing.
4. ALPA determined that the physical evidence showed a fractured bolt to the right outboard aileron caused it to free float up and the 727 to turn to the right and off its heading. The yoke turned to the left as the Autopilot Heading mode was on trying to get back to the preset heading. The vibrations were due to the left spoilers raising to aid in roll control. Then the Yaw Damper rate gyro or coupler sensed discrepant rudder inputs which resulted in a lower rudder hardover that sent the plane into a dive. On the 727 the outboard ailerons lock out when the flaps are retracted and movement of the rudder is greatly limited when the flaps are retracted so with a fluttering outboard aileron and a lower rudder hardover the pilots were left with insufficient aileron and rudder control to recover the plane. When the gear extended the right gear overextended which ruptured the System A hydraulics cooling line that centered the lower rudder and allowed them to recover. The No.7 was misaligned and didn't lock into its locking mechanism so the only thing keeping it retracted was System A hydraulics and aerodynamic forces. With System A gone the aerodynamic forces of the dive caused it to extend.
Additional notes:
- Hoot Gibson stated before the upset the plane yawed to the right, paused and then yawed right again. This is corroborated by sharp heading changes on the Flight Data Recorder. Only the rudder(s) could have caused this.
- After they recovered, the Flight Engineer reported they had a fail flag for the lower rudder yaw damper. This would only occur if the rate gyro malfunctions or lost electrical power.
- Days after the upset the accident plane was taken up on a test flight and they went up to FL390 and extended the flaps and slats to the 2* degree position which caused severe vibrations, not slight vibrations as the passengers and crew of TWA 841 had testified. The Captain of this flight testified in court following a passenger suing TWA and Boeing for injuries that he did not believe the pilots had extended the flaps and slats in cruise flight.
- Actual flight tests on a 727-100 determined that had the pilots extended just the flaps and then the slats extended there would be a sharp pitch up as per the Flight Data Recorder but there was no sharp pitch up on TWA 841.
- Had the pilots extended the flaps in cruise the passengers seated over the wings would have heard the distinctive growl of the flap motors as the pilots extended the flaps and then retracted them but none did.
- The NTSB’s own simulator tests showed the slat would have ripped off at no lower than 30,000 feet, not at 8,000 feet in actuality, and for their theory to be believed, the slat remained attached even at the speed of sound. Boeing engineers determined that the slat could not withstand a speed greater than 363 knots while extended, so the slat would have to have ripped off at an altitude close to FL390.
- The physical evidence showed the over extension of just the right landing gear and the inboard flap track - a pattern of differential damage - was consistent with a large left wing forward sideslip angle present of the gear extension.
- The co-pilot stated in an interview in 2015, months after Hoot Gibson died: "I can’t say with absolute certainty what caused TWA 841 to roll over and dive some 39,000 feet, but I can say with absolute certainty that the investigators got this one wrong." Why would he continue to maintain his and the FE's innocence over 35 years later if they had indeed caused the upset? Was he worried that Hoot would throttle him in Heaven? Nothing would happen to them now for coming clean.
Cheers.
This was a fine vid to wake up to.... much appreciated, Greg
This channel is epic!
It's nice to hear stories about interesting incidents that end well as far as nobody getting hurt.
I'll sometimes switch the air in my car to recirculate when there's smoke outside, and the number of times I forget to switch it back is embarrassing ...I can absolutely see the sense in sticking to standard procedures, even if the deviation is not dangerous in itself. Fascinating couple of stories, thank you!
Fabulous video Greg - really interesting operational detail there.
Having lived under the flightpaths near Hartsfield International, I can absolutely attest to the noise of the 727's turbojets, especially on takeoff. The only thing louder was the old Delta DC8 stretch that was still in service into the early 1980s, and it fricking *screamed* when it came and went.
Thanks for this addendum to your excellent 727 video from the other day, I really enjoy the change of pace from the usual WW2 fighter topics!
The 727 is (and always will be) one of my absolute favourite airliners, I really miss the ear-splitting roar of those JT8-Ds. Unfortunately I was too young to fly on one when they were in their prime, I do remember flying on one of the last Ansett -200LR flights with the extended range fuel tanks in early 2001, my airplane obsessed 10 year old brain soaked up every bit of that flight, it felt special!
Ear-splitting roar - yeah, I'll say. This A&P had to do B727 engine trim ops under the cowling, at full power. I could only wear the Headset for comms with the cockpit. Result - I lost some hearing and eventually ended up with tinitis. Worked on Pratt engines for many years in my career: Flightline ops (A & B checks / engine change crew); Heavy Overhaul (C and D checks, Gear and Rigging crew); Engine Overhaul; and Experimental Assembly & Test at PWA in E.H., CT. I miss working on the B727 - she was and will always be my favorite, even though it was sometimes a "love-hate relationship."
I flew on quite a few commercial airline flights. The 727 was my favorite as a trip-jet and clean lines. I would have like to have seen more modern engines, though.
Previous video he says the 727 was quiet (even said it was called the "Whisper Jet") and this video he says it was very loud.
Does that mean it was quiet compared to the other jets in the 1960's but 20 years later it was loud compared to other newer aircraft?
@@toddsmith8608 Stand next to a B-707 running at TO power. Those JT3Ds scream like no other turbine engine. The JT8D is a relatively quieter engine.
@@hiturbine user name checks out
You are a walking encyclopedia Greg, thank You mate!
I remember us talking about the "Hoot Gibson maneuver" at the time. Thanks for bringing it back to mind! And the cross feed start is an age old trick in more than PA-31s...
While I am not that familiar with the Piper, but wouldn't all the fuel being burned from one tank make the side not being used heavier causing the trim to have to be constantly adjusted giving the pilot a clue that the aircraft was burning more fuel on one side?
Not really because of the amount of fuel involved, location of the tanks, aileron trim, short flight, and the fact that the planes at that company were all beat to hell and bent. They didn't fly straight anyway.
That was my thoughts, but Greg's comment sounds plausible.
@@GregsAirplanesandAutomobiles Thanks for clarifying, I had the same thought while watching
that is just a wild fact to hear@@GregsAirplanesandAutomobiles
Good to finally see your face! Thanks for all the interesting posts.
I too generally agree with your and the NTSB's conclusion on the 727 dive. During my 36 years flying for United, about 15 on the 727, we always knew about the "Gibson Trick" and talked about it even before the incident, but nobody I knew ever thought it was a good idea or suggested using it. Maybe that's why my career was so uneventful.
But...
When I was upgrading from the 727 to the DC10, one of the guys in class had come in from the Continental merger, and related an interesting story. He was a 727 FO there and had a totally uncommanded outboard slat extension while maneuvering at low altitude and airspeed. The airplane was controllable under those conditions, they landed safely and wrote it up in the logbook. Several weeks late he tried to find out what had caused the problem, and suddenly nobody knew anything about the incident. Hmmm...
Conversely, I watched a situation when one outboard slat remained extended when going from flap 2 to flaps 0, it took a LOT of aileron to keep the wings lever.
this might be strange, but i really like how you set up this shot, and the colour grading too.
Always wondered about that incident. Thanks for the expert commentary!
Fascinating deep dive into how the 727 works and a likely scenario for a nearly tragic incident. Keep up the great work!
Great video once again!. I really enjoy and appreciate any aircraft videos on any subject matter which you produce!
Good video, but I have some comments. I was a TWA F/E at the time, dual qualified on the 707 and 727. You say that pilots used this flap trick to fly at higher altitudes to save fuel. I can tell you that in all my years flying F/E I never once had a Captain suggest pulling that stunt and I never had any of my fellow F/Es tell me a sea story about using the technique when airborne. I suspect it has been done more than once, but I am quite sure it was not at all a common procedure. If it were anything other than a theory and perhaps a very rare occurrence, surely I would have met someone who said to me, "Sure, I tried it once". But that never happened. Not even a "I heard about a guy once................" story. I am convinced that it was pretty rare.
I'm reminded of the story every high school kid heard about the $100 Corvette where a guy died in it and they couldn't remove the stench since the car was fiberglass. it was always two states away so even though every young boy heard the story, nobody ever actually found that cheap Corvette.
Gibson said that neither he, his F/O, or his F/E even knew about this particular way to "trick" the flaps. That was good for a laugh all around.
I suspect there were some Captains who didn't know all that much about the systems. That's why there was a Flight Engineer on the airplane in the first place. But I guarantee that many Captains did know about it, the majority of F/Os, and every single F/E I ever met knew exactly where that circuit breaker used to disable the leading edge devices was located. They even mentioned it in our ground school class. But being common knowledge doesn't mean that it was used.
I will emphasize again that not a single time in my career was this procedure suggested nor did I ever meet any pilot or F/E who would admit that they used it in flight.
Nobody will ever know the true story, but at the time we all pretty much thought that Captain Gibson and his F/O and F/E were all in on it. They developed a story and they all stuck to it. The cockpit voice recorder erasure was no doubt done on purpose or at least that was the common belief.
I didn't say anything about this being to save fuel. The fact that you mentioned that indicates that you have at least heard of this, even if you yourself never did it. I'm curious about when you were at TWA.
I thoroughly enjoy listening to your videos. Thank you for producing them for us.
My Dad worked for TWA as an electro mechanic during that period of time. He always told me that you could pull a breaker and the leading edge slats would extend without the flaps. And it also killed the safety interlocks. What happened in this case was that one deployed before the other and caused the snap spin and subsequent descent. Interesting to hear it differently. Thanks for sharing!
Hi, it is very good to see you in person,i can now relate to the voice in your excellent videos.cheers Roly🇬🇧.
Wow!
Excellent overview. And plenty of great insights to be gathered here.
Hi Gregg! I'm not an airplane buff, but I love everything you post.
Your no nonsense approach and knowledge towards all subjects you hadle is keeps me hooked.
Keep posting please ❤
Enjoy your detailed explanations. Thank you.
Fascinating stuff Greg. I learn something new every time I watch one of your videos. Keep up the great content. Looking forward to whatever is coming up next.
Also, well done for doing some videos with your face in front of the screen. It humanises you!
If Greg can recount the glory days in the B727, maybe it's time you talked about the 'good' ole days in the San Antonio Sewer Pipe. It's still in active operation you know!!
I have to wait until I retire before I tell those types of stories.
@@GregsAirplanesandAutomobilesI will look forward to that event. (the vids...)
A Cargo plane with JATO!?!?!?!?
@@GregsAirplanesandAutomobiles How many checkrides have you got left, young man?
@@GregsAirplanesandAutomobiles I mean this is the nicest way possible...
I hope that's soon. Would love to hear your personal perspective on things
This has been my introduction to your channel. Nicely done. Thank you.
Hmm, this was just a quickie video to answer some questions that have been coming my way. It's not my usual type of work.
Greg I have loved your vids on civilian airliners and you have covered my two favorites the DC 7 and the 727
Hi Greg,
After listening to your great content for years - I finally know what you look like!
Keep up the great work.
Cheers from Australia.
Great video. Talking about noise reduction. Taking off from Southampton (UK) the procedure was to take off and climb to some height, then when full banking had been achieved throttle back. it was the best white knuckle ride ever conceived
Yup, we called that setting "cut-back-thrust" at the airline where I flew these. I didn't like that procedure at all.
Spent over 5 years as mechanical design engineer on the 777 Flight Deck Design Group, through the heart of the design up until first delivery. The guys that represented the interests of the airline pilots (they were still Boeing guys) were great fun to talk with. Around 1995 they brought up this story, and those guys made it clear everybody knew what happened, but they got away with it not being formally recognized.
You KNOW you're in trouble when there is dramatic theme music.
Man i love this channel. Greg, you are amazing.
Thank you Greg , a first class video . Very informative and extremely well presented .
Really good video and explanation, I shake my head how much grief Boeing is in right now and how tarnished there reputation is This is the Company who everybody in the world knew as the Belt and suspenders company in engineering really enjoy your technological take care
Thanks for settling that.
Howdy Greg
A couple of points: T. W. A. and all the other airlines were
quietly encouraging their flight crews to push up their altitude so
reduce fuel consumption. This was during the second Oil Crisis
in 1979. and the price of Jet Fuel had gone through the roof. So,
it was known that anything that a flight crew could do to reduce the
gallons per mile was OK with Management.
Second, the Flight Crew did NOT erase the tape. The tape on the
Voice recorder was 30 minutes long, and was a continuous loop.
After landing, the crew taxied the rather bent bird up to the
terminal, had the stewardesses unload the rather bruised and
shaken up cattle from the back, and then sat parked at the
gate with the engines running at low idle. For about 20 minutes.
Which meant that the CVR kept recording, over-writing the section
of the tape when the aircraft was out of control. And the crew sat
there, silent, for then entire time, except for one member of the
crew, who said, "Shouldn't we......" and the Captain cut him off
by saying, " SHUT UP !!!!!"
And the tape kept running for another ten minutes, and then they
shut down the engines. Which covered their asses just enough
to allow them to keep their jobs and American to avoid a nasty
scandal and horrible lawsuits.
It was Tex Johnson who testified at the NTSB Hearing who
explained to the experts what had happened. Nobody could
prove anything. but Tex laid it all out for everyone to see.
And ALL the Airlines quietly told the Flight Crews to stop fucking
around with the flight controls !
There are a number of theories about what happened. I was very clear that the one I put up is one of several. As for the reason the CVR was erased, there are several versions, but no solid way to prove any of them. Even if the story you told is 100 percent accurate it's still very suspicions that they sat silent for that long and nobody thought to pull the CVR breaker and save the evidence that would have exonerated them.
This was a TWA 727
@@GregsAirplanesandAutomobilesexcept there was 9 minutes of audio on the CVR. NTSB never reported on it because it contradicted their erasure story. Lawyers were fighting them on it even during the investigation to disclose what they found on it.
@@bkailua1224Yes
"And American"? Shouldn't this be "And TWA"?
I was a fairly new part time flight instructor at a small flight school in Michigan at the time. As I recall, this happened near Flint, MI. I believe they made an emergency landing at Detroit.
Imagine you just sat down at a bus station with a 20 minute wait, and a man in a flannel shirt proceeds to tell you everything in this video.
Flannel is the ultimate clothing material.
Wait...a jet liner pulled 6g's and not only did it survive but it was repairable? My lord that is a stout plane! 😮
Thanks Greg. The odd 727 freighter flew in & out of Sydney in the early 2000s, mostly DHL.
Had a house in Sydney, very near but between the runways. 747s etc took off from 'the front runway'.
727s used the new '3rd runway' (yes, only 2 now lol), up much higher behind & had distinct noise.
_PS: The old BAe 146, still in basic Startrack livery, sits on unloved at Coolangatta/GC._
Love your vids, clear explanations, informative for novices.
Thank you Greg. I can listen to stories like this all day long.
Since you mentioned the Piper Chieftain, I have a story related to system knowledge. In my early aviation days, I was first officer in the said aircraft type flying oil workers from Norway (Kristiansand) to Germany (Willhemshaven). Just a few days earlier, the owner of the aircraft had checked me out in the Chieftain. It was winter, and the owner told me that the cabin heater, which runs on avgas, should only be used in flight. Without sufficient airflow, the heater would overheat and trip a safety switch. This switch could only be reset when the aircraft was on the ground. I promised to remember that.
For the taxi flight, a newly hired pilot would be captain. It was a cold winter day, and when he taxied the aircraft from the hangar to the terminal building, he turned on the heater. I was not onboard. The heater must have overheated just before he parked the aircraft in front of the termainal. The passengers boarded, and off we went. After take-off, the captain asked me to turn on the heater. It didn't work. So, I asked if he had used the heater during taxi. Yes. We could not turn back, because we had a tight schedule; the helicopter that would carry the oil workers from Wilhelmshaven to the oil platform could only operate in daylight, and the days are pretty short in the winter in northern Europe. At cruise, it was -15 degrees Celsius outside and -14 inside. Thankfully, we had warm clothes, and North Sea oil workers are tough guys. But it was a relief when we had landed and could and heat up in the terminal building.
The return flight was warm and cozy.
I remember that heater quite well, I hated that design. Thanks for sharing. I really like the Chieftain other than that heater issue.
I have a couple of thousand hours in Chieftans and I remember being told never to run the Janitrol heaters on the ground unless you left the heat lever all the way to the left in the minimum heat position . Even then each plane was different and some you could get full heat in flight and some you had to limit how far you pushed lever over or you would blow the thermal circuit breaker. The thermal circuit breaker was behind a small panel on the outside right side if the fuselage just behind the nose about where the props were. The only way to reset it was to unscrew all the DZUZ fasteners and reach in and rest the button, which is of course impossible in flight. I flew with one guy who never had that C/B trip and always had plenty of cabin heat and I could never figure out why. Years later he told me that he would open the panel before we left and wrap tape around the C/B so it couldn't pop......I am not advocating doing that.....messing with Janitrol heaters can and has caused fires and that is not a good thing.
Greg, I love your videos. I noticed you didn't mention the quietest version of the 727....The 727-10QF. In the 1990's UPS converted their 727-100 fleet, replacing the center S-duct and the JT8D engines with three Rolls Roys Tays. It was the only 727 stage 4 noise conversion. It had its good points but also some issues. The 727QF was actually flown as a passenger aircraft from 1996 to 2001 by UPS.
There was an interesting event, that we called the 727SF (silent freighter), known to almost no one outside of the UPS community, of a 727QF that had just started a descent over Chicago and lost all three generators. They actually lost all 3 engines due to a mistake in fuel management by the flight engineer. It wasn't recognized by the crew at the time as the thrust levers were at idle for the descent. The crew diverted to O'Hare to land on 04 R and at 3500MSL the F/E says....I have a stupid question.....do we have any engines? That is when they realized it was a 3 engine failure. That was a major CRM teaching moment at the time.
Suddenly, the crew then knew they were going to crash short of the runway but were able to get one engine started at the last second which was enough power to get them to runway 04R. But since it was a freighter that "didn't crash".....no one ever heard about it....
WOW.
Noise abatement issue: It has frustrated me to no end when some dumbass decides to do housing deveopment adjacent to an airport, and then the eventual residents complain about aircraft noise. Simple solution - Don't construct housing around airports!
Absolutely! As a kid I had a job at a small airport that was established in the 1920s in the middle of nowhere. In the 1960s housing was built nearby and the moaning began. That airport is still there to this day, but it was a struggle to keep it open.
Same's going on with Laguna Seca. Well, that's the excuse anyway. There's some obfuscation about the identity of the complainant.
And Bridgehampton on Long Island. Great track in the day.@@brianargo4595
Fascinating account, thanks for covering this. Since childhood I've always paid a lot of attention to the flaps and slats on airplanes during takeoffs and landings, but I didn't know there was some usage at cruise, authorized or not.
Love your stuff, Greg! Thank you!
Love these "trade secret" stories about planes. Awesome video Greg.
Thats a really good looking lighting but I recommend adding something soft to the walls to dampen the sound echo, it makes a huge difference
Thx Greg! Well done
Great insight and video. Ive never heard of that crash, and the amount of violations today that they did to get to that situation is quite big.
Love finding all I can about the 727 , beautiful looking jet and that wing was a masterpiece. I just subbed .
Thank you for the insight !
Greg you are just GREAT, your videos are so interesting.
There was a Boeing engineer who after he retired came clean and said asymmetric slat deployment was not a unknown occurrence. I knew Hoot personally and if he hadn’t been a competent aerobatic pilot they would have lost the plane. There’s a Boeing and TWA coverup, the plane had a inadvertent slat deployment and then a high altitude upset. Hoot was promoted to the 747 prior to retirement. A slat deployment would certainly cause an upset at FL390.
That's one version of the story, but I'm not buying it.
@@GregsAirplanesandAutomobiles Hey Greg, are you going to start giving your opinion on other airline accidents? Perhaps some on the airline in which you fly?
I don’t believe there was a coverup by Boeing and the NTSB. I believe after the investigators found that 21 minutes of the 30 minute CVR recording was blank that they were so tunnel visioned in that the pilots had caused the upset that they didn’t let the evidence lead them to a conclusion and instead let their conclusion be based on a pre-determined notion. In 1990, ALPA (Airline Pilots’ Association) determined the physical evidence and the FDR indicated the upset was mainly due to a yaw damper induced lower rudder hardover and when the gear was extended, System A hydraulics was lost and the lower rudder centered allowing the pilots to recover. The slat was lost due to the loss of hydraulic pressure as it didn’t lock into its locking mechanism while the other slats did. Simulator tests showed that the slat would have been lost at no lower than 30,000 feet not at 8,000 feet in actuality and for the NTSB theory to be believed the slat remained extended even at the speed of sound when Boeing engineers determined it could only remain extended up to 672 km/h.
There’s a great article about TWA 841 on Emilio Corsetti III’s website: “Thinking of Hoot”.
I remember the TWA 841 incident from my time as an A&P in Michigan. I wasn't working with an airline, so it was an interesting news item I'd never heard the full story on. Thanks for the insight!
Your story emphasizes how at times transportation and industrial accidents can be caused by people well-meaningly tweaking the rules. Sometimes if already in an emergency situation, off limit actions may be the last chance, but don't try to second guess the engineers.
Fascinating stuff, thank you!
I heard this story 40 years ago, and I believed it. As a TWA new hire in 1986 I was set straight. I spent 12 years on the 727 and no one ever talked about this trick. I did talk to an investigator who said it was a lower rudder hard over. And a union rep who said that Hoot walked into a Star Chamber when he testified at the hearing.
By 1986 nobody was doing it any more, and for obvious reasons.
But the TWA pilots I flew with had been flying the airplane for 20 years, and all vehemently denied ever hearing about it. Someone at another airline came out with that theory. It doesn’t hold up.@@GregsAirplanesandAutomobiles
I don't know what they heard, but I find it hard to believe that all those pilots "denied ever hearing about it".
@@GregsAirplanesandAutomobiles Oh, they heard the story, but no one ever heard about anyone actually doing it. Most had flown with Hoot, and they said it would have been very unlike him. I realized the story was fabricated, repeated endlessly by people who knew nothing. I’m surprised and disappointed to hear it from you.
Pretty Good. One comment, on the CVR. At my airline, it was not SOP to erase the CVR after flight. Almost every instance of erasure was because of an immediately preceding event. That said, there was one spectacular event I was involved in as the flight engineer, where we consciously made sure we left it running, to OVERWRITE the information. Something of a risky proposition, but a whole heck better than overtly pulling the c.b. (on edit: I shouldn't leave it at that. The captain had screwed up big time, and I and the c/p had to take some actions that might have been questioned, to get the op going again. Like possibly backing up a 727? Onto the runway? Using thrust reverse? Well into compressor stalls? I mean, not that, but...maybe. It was a long, long time ago).
I'd had it from an electronics tech that the DC office of the the FAA, where they did the voice recovery on those analogue recorders (30 minute loop), could dig down into noise to retrieve up to 6 layers of conversation. With enough work, they could extend that 30 minutes to a couple of hours.
As an aside, that same office did the work on the Challenger recorder. They had the data by the night of the day they recovered the box. Of course, that was not disclosed to the public for 10 years. A controversial decision, in that they lied.
Six sounds dubious, but two seems unchallenging. The Wikipedia article says that the cockpit erase used a bulk erase feature, which if true would randomize the entire tape. An overwrite doesn't work as well for hiding earlier recordings, if only because the new track doesn't precisely track the old one, meaning that on one side or the other of the newer track the previous track will generally still be "visible", and in some places more than one track. But to listen to that you would need special equipment and you would probably only get fragments of other than the immediately previous tracks..
Hi Greg. Quality content. And Man, I imagined You totally different :)
My brother, now a long-retired airline captain, told me of this a good twenty years back. The version he had heard was much as you say, Greg, but with one addition. I have to doubt that addition now as I suspect you would have heard of it. But here it is:- When the investigators played the voice-recorder tape they couldn't hear a thing, until one of them finally played the tape right to the end, to hear the words 'Now let them try and work out what happened.'
"Now let them try and work out what happened" with diabolical laugher in the background!
I haven't heard that, if true, it's damning evidence.
Not sure if you covered it Greg, but I heard the reason pilots would push the max altitude limits was pay related - they got bonuses for fuel savings. This event put an end to the practice. Interesting to hear if that story has some truth to it.
Your lighting is perfect, effin' perfect. And it changes, obviously you planned it. Kidding. Seriously your lighting is what the world looks like and I like it.
Great video.
Ann Getty’s super 727 N311AG had the rear flap “up stop” permanently at the “2 position” and flap gap seals installed to cover the extension gaps. This mod was so good it was incorporated into the plane with the super 727 and didn’t need the circuit break pulled. With -200 engines on outboard it was faster than any corporate jet in existence, faster than 747. Guess how fast it was with the nose slightly pushed down beginning at top of its high altitude decent, yep it was that fast and could take it.
Yes, well, I expect Boeing would have had something to say about that mod.. I don't believe your story, Sorry.
Some of the reasons are: The A/C Pack Fans would run continuously; The Lower Rudder would receive 2400 psi continuously, rather than switching to 800 psi for high altitude flight- resulting in a LOT!!! of muscle for the Lower Rudder/Yaw Damper combination.; The outboard ailerons wouldn't lock out in faired position- they would have over 50% of normal (Flaps 5º and beyond) travel, resulting in VERY sensitive roll control- not what one wants at high altitude, and would result in possible "Aileron Reversal" due to wing warping- again caused by outboard aileron travel. There are good/valid reasons why TBC built the airplane the way they did, based on experience with: B-47, B-52, KC-135, B707, OK???????
Great channel! You are great at extemporaneous speaking, and in this case speaking about one of my favorite airplanes 👍
PS- the room ambiance can be dampened with a lapel mic for better intelligibility.
Super fun to get to actually see the man behind The Voice™ ❤
I love how you can explain things simply enough that purple can understand what's going on even if they're not airplane nerds.
Would you mind reviewing defensive tactics in the DCS P-47 next?
Agree!
Lowering the landing gear could also cause a pitchup. JAL B747 that had uncontrollable descent over the Pacific Ocean was only saved when uplocks for gear failed allowing them to land at SFO.
I'm going to assume this also wasn't Robert "Hoot" Gibson of the Rock'n'Roll Express. Great presentation Greg, I liked this smaller, informal, but easily digestible format.
Now that's some insight knowledge!
Thanks Greg. 35k in 1 minute and get it under control, those are some good reflexes and skill.
Thanks Greg Awesome Explanation 😊😎😀👍🏼
Greg is far younger than I imagined.