NTSB Preliminary Report Hawker 900 Stall Test
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- Опубликовано: 3 мар 2024
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Hawker maintenance technician here. Just to clear things up that I'm seeing in the comments misinterpreting the nature of this test requirement.
The test not only verifies that the SIS works correctly, but primarily ensures the aircraft stalls correctly as adjustments to the stall triggers can be made to correct conditions of premature rolling tendencies. It is important that the aircraft stalls straight ahead in normal conditions. In most cases, the complete stall warning, identification, and recovery systems are fully functionally and operationally tested on the ground using AMM procedures BEFORE the stall flight is conducted. It is a very thorough systems check. This ensures the AOA vanes, stick shakers, stick pusher, and warning indicators are working properly before the flight is conducted.
so what are the odds that the maintenance was wrong and that actually the plane had off-nominal stall handling? in other words, if the test was "failed" by the plane itself, it may not at all have been the pilots' fault (despite busting the test ceiling)?
.... Is the test necessary in the air? If maintenance can be done to replace and replicate a repair and everyone understands the difficulty of this manouvering, why do it?
@@UnshavenStatue Unlikely. It's rare to need an adjustment from the base settings defined in the AMM/SRM or from the measurements taken prior to removal. Ultimately they just control which wing stalls first, and the idea is to make both wings stall simultaneously. Mis-rigged triggers shouldn't effect recoverability from a stall, either.
Furthermore, the technicians at Grand Junction are some of the most experienced in the business, and have a great track record.
@@kirknewton100 The test is to ensure that the aircraft stalls predictably in an unintentional stall scenario. As morbid as it is, it's better than the alternative of killing passengers. Additionally, the Hawker 125 series are not the only aircraft that require this, though as technology advances and fly-by-wire is becoming commonplace, it is becoming rare.
Highly unlikely.
A FlexJet crew did this same exact test and barely survived. I believe they bent the airframe during their recovery. It was shortly after the Flexjet crew had their close call and I was tasked with doing one out of Little Rock. We did ours at 15,000. I still didn't like doing them. Former Hawker driver here with about 3500 hours in type.
Back when I was a kid working maintenance at Eastern Airlines back in the 80's, I went on a post D check test flight on a 50 series DC-9.
The pilots did a little bit of EVERYTHING on the flight. Fu*king WILD!
I had no idea what was about to happen. Max performance take off. Max performance braking. LOW and EXTREMELY slow maneuvers. And most dramatically STALLS!
If you know, you know, the short 9's were rockets.
I'll never forget standing at the cockpit door holding on to the two handles on either side of the cockpit door looking through the windscreen as the pilot (who was smoking a cigar, btw) applied flaps and yoke backpressure into stall: "Looking at sky, looking at sky, looking at sky. A moment of zero gravity. Looking at ocean, looking at ocean looking at ocean!"
My years at the mighty Easten were the best. I'd have loved to kick Frank Lorenzo in the balls. RIP Eastern Airlines. *wipes a tear*
lol, I was there at the same time. I'm assuming Miami? I went on a couple of those post D-check flights on 727s (although we always referred to them as LAFs [Local Acceptance Flights]) as a mechanic in bdg 22, bay 40, cc 593. I also remember them doing overspeeds as well, which made the air feel really hard. At lest once we did touch and gos at the Everglades Jetport which was the airport that never was. Good times..
I was flying a square piece of shit called the Shorts SD3-30 when you guys entered your spin. EAL was actively hiring but I refused to send frankdouchbaglorenzo a resume. Then came the EAL strike and I happily paid a union assessment to fight FDBL in support of the guys walking the bricks. Then for the next 20 years I carried an ALPA Yellow (Scab) Book. Using it, I managed to refuse several
F-ING SCABS my Jump seat. Later on I flew with a LOT of former EAL guys at Brand X. Almost all of them were great. Long live EAL, "The Wings of Man".
@@Part_121didn’t Eastern have “Whisperjet” painted on the side of their 727s? Those things did anything but whisper. Still my favorite jetliner.
@@a.n.7863 Yep, and "Whisperliner" on the sides of the L-1011s. Our credit union checks, I believe it was the checks, had "Whispercash" as a faint watermark.
Same thing Mr. Lorenzo did to Continental Airlines-(via the friggin unions who caused it all ) and lost the best job I ever had with COA LAX DC-10 program
jeez the CVR from this is going to be scary as heck.
We're not going to ever hear it (but the transcript will probably be haunting enough).
@@R2Bl3ndThe NTSB only releases transcripts I assume?
@@PaulLoveless-Cincinnati Correct. CVR recordings are held sacred by the NTSB. Only a literal handful of people will ever hear them. And transcripts will never contain any "private banter" between the flight crew, only what's relevant to the investigation. The crew took their private conversations to their graves, and so will the NTSB.
@@PaulLoveless-Cincinnati yes, and not even always that. It was made illegal to release the CVRs ever since the recording of Delta 1141 was leaked/released.
@@wewd🙄”banter” is always included in CVR transcripts.
Im a Hawker guy with types in not only the Hawker but numerous other jets, and have also flown numerous other Turboprops
No way when I operated them I would do the stall test. I hired a test flight crew for post maintenance test flights.
I have over 11,500 hrs and over 6,500 hrs as PIC in Jets but I know my limitation
Respect to you and especially all the test flight crews!
That's why you are alive today. Smart decision making saves lives.
I appreciate you pointing out the disorienting nature of being in clouds, etc.
I remember the Bell Cobra had a warning sticker right over the anti collision light switch about possible vertigo if left on in clouds.
Hell I was sitting on a tug with the brake on next to a hangar door (the horizontally sliding type) and practically stood up on the brake pedal when someone opened the hangar door because I was convinced that the aircraft, the tug, and me were all drifting forward!
When most of your field of view appears to be moving in one direction, it becomes virtually IMPOSSIBLE to get a frame of reference.
I'm just on a desk chair flying MSFS in VR but it's really weird what clouds do to a brain. Quite amazing how you can get tricked into thinking for example the plane takes a dive while it's just because clouds roll over you. Same with flying in between mountains and suddenly (unprepared) hit compact clouds. I'm sure my heartbeat goes up even when just sitting in the chair with VR.
For those of us who have nothing to do with aviation whatsoever, but have inquiring minds and love digging deep into the facts of how things work (and how things go wrong), this is the most fascinating and informative channel on RUclips. Thanks, Juan! 👑
As an avionics Tech I also had to ride on the "post D Check" flyback. Always at night, and let me tell you I observed some wild "Lets see what this thing can realy do." antics. Boeing 727-767. Thank you sir I appriciate your honest non-media hyp reports.
I’ve been involved in post maintenance flight testing for a couple different airframe types for about 10 years. We have an entire operations manual dedicated to this program and we employ two pilots who’ve attended test pilot school. We’ve had to delay test flights several times because we didn’t have the right weather conditions (similar limits to what’s in the Hawker manual). Not once have our team considered making an exception to those requirements, and this accident is an excellent example as to why. Stalling an airplane is not a “normal envelope” operation for a swept wing corporate jet and it should only be done by properly trained test pilots. IMHO, it’s pretty disappointing that the manufacturer has documented this as something that rank and file pilots can perform.
Jet, swept wing, post maintenance stall test; take the day off, hire a factory test pilot who is not a close friend👍
Dark
Private jets: Which ever way you look at it, luxury is a very strange thing. It reminds me of the owner of an English stately home who had his pile designed and built so that he would never encounter his servants (or ' the help' as some Americans coyly put it).
@SubTroppo I think you'll find most stately homes built in the UK between say 1600 and 1900 were designed with ample "servant's stairs" and passageways so that the servant's could go about their business and not disturb the owner, his family, and guests.
@@pulaski1Agreed, but as I understand it this chap went further much further than the common aristocrat - to the extent that he sacked any servant he set eyes on. I suppose that unless house was very carefully designed there would be a rapid turn-over of servants.
@@SubTroppo, sounds like a pompous @$$! In the end he’ll have dirt tossed on top of him just like everybody else.
The violently discontinuous nature of the type of aircraft's behaviour is scarily captured by the video shown in this one. It is sobering to see just how bad it gets so fast. This procedure is a real heart stopper.
I worked for Raytheon/Hawker Beechcraft in production hawker flight test in Chester England then Wichita and have been on hundreds of stall flights and we always set the stall triggers at nominal and ensured the sealer was cured and the profile was flush between the leading edge and wing skin. The POH and MM are very specific for a reason unfortunately.The crew always started at FL18 not 20, this is a very sad outcome and maybe we’ll never know what happened. RIP
I have a hard time believing 2000ft higher would actually make a huge difference and could explain what happened. Do you remember how they came up with FL18 und what the margins are....?
@@FlyHighAndFarI think they were trying to make clearance above clouds (going higher) and then stalled back into those clouds too quickly to ever regain orientation, and then finally complicated by the local elevation.
It’s interesting that you mentioned the sealant.
I had a departure from controlled flight during production stall testing in a CRJ 200. The PRC sealant wasn’t fully cured when we received the AC for first flight. Initially, the sealant profile looked good during the walk around. We conducted the engine runs, and anti ice checks, and then took the ship up for first flight. Unknowingly, the PRC extruded itself during the wing anti ice checks and set up a 1/8” ridge at the leading edge/wing plank joint.
Needless to say, the stall was not benign.
While I’m not familiar with the Hawker, I certainly understand the effects of wing leading edge contamination.
@@wadepatton2433 Agreed.
@@CLdriver1960The sealnt between the wing proper & polished LE is a PRC-Type product. However, the joint between the TKS Strip & polished LE (gap) is filled with a two-part epoxy with a critical application: No higher than flush (moderate concave acceptable). Was explainded that if protruded above flush, it Would affect airflow at critical LE area, effectivly reducing lift. Also, stall triggers are not equal Left and Right, with specific settings for each.
I flew with Paul Berliner quite a lot at ATA Airlines, back in the late 1990s and saw him a time or two in the early 200s, befire the last bankruptcy. Paul was a fine pilot and captain. Fate really is the hunter; killer situations can happen to anyone. Always be ready for sh*t to hit the fan and take the action you need to stay alive.
"Before the last ATA bankruptcy." Then we all scattered in the winds.
During the Vietnam war, more than one F4 was lost to a stall during ACM. The flight manual says if recovery is not completed by 10,000 ft, eject.
If the stall happens below 10,000 ft…..
At 20K... getting too comfortable at doing these tests. Only takes once. Thanks for following up. Always great information with your knowlegeable input.
Sounds like complacency is a big factor here - which also probably meant they didn't follow the stall test procedure by the book, maybe held it a bit longer than they should have or something of the sort. Which then, like you said, meant they are on their own.
Unbelievable that pilots this qualified didn't make it out. RIP
Yep. Game over. RIP.
Sadly, high qualifications don't mean errors can't happen.
Indeed. It's an unforgiving environment. Even great pilots make mistakes. I am saddened.
Yes, agreed
They were outside of the envelop...not by much though.
I have given and received a lot of training in swept wing aircraft in my days and can tell you that even after thorough briefings the first stall, especially the ones at mid and high altitudes, almost always result in a secondary stall since the initial break was held too shortly, for various reasons, and the recovery was performed too abruptly, also for a variety of reasons. Usually, after that first stall significant learning has taken place and the next stalls are much better overall!
I always tell every Pilot, if you fly an aircraft with a Pusher installed, there is a reason why the manufacturer did so and it’s usually because the characteristic of the aircraft are less then ideal and usually violent once a fully developed stall is encountered hence the Pusher, never let it go past that unless you are either a Test Pilot and or have a spin chute.
Wow. So glad there is a CVR/FDR to help clear up the exact details. It seems to me there's still a chance the repair work was done wrong in some way and they couldn't recover as expected but regardless, a tragedy.
yeah... like there should be a warning in the test procedure "if the craft was not repaired correctly, following these directions could unalive you, let alone the craft."
hopefully the post crash investigation goes over the pieces with a fine tooth comb for it's going to matter whether the repair was done right or not.
is there any way to do this kind of test in a wind tunnel?
@seekingthelovethatg odmeans7648 they are tested on the ground. Stop making stuff up about things you don't understand.
Thanks for the preliminary report Juan,shows no matter how experienced you are accidents can happen,may they R.I.P🙏🙏🇦🇺
*preliminary
@@DeltaEntropy The final preliminary report.
Hey Peter, I've seen your handle appear in other comment sections of aviation videos here on yt. I think you commented on one of my videos even 👍
At high level of experience, accidents are in many cases created by overconfidence which make people overstepping boundaries a beginner never would try. Thets a well observed phenomenon.
@@oliverherzog7702 Yes, very good point, & I agree 👍
Thanks for another very informative video. I’m surprised that the crew elected to conduct the stall test 2000 feet above the maximum approved altitude. One big concern that comes to mind is that the stick pusher firing point is only valid to 18000ft.
Another possible issue may have been accumulated ice on the wing. Even a trace will have a major degradation at high alpha.
Another possibility is wing contamination from semi, or uncured PRC sealant, extruded from between the leading edge and the wing plank.
Condolences to the families and friends.
When you say that the "firing point" is only valid to 18,000ft, do you mean that above that altitude it may delay the stick push to the point where the stall develops to a dangerous point (e.g. a "deep stall") before it activates?
I think the amount of experience of the crew led to overconfidence and therefore a willingness to perform the test outside the required parameters.
@@mikekeenan8450 Full disclosure: im not familiar with the Hawker, but I am familiar with production and certification testing on a different airplane type.
A typical Stall Protection System is altitude compensated (Equivalent Airspeed). During certification testing on the Hawker, the stall tests were either not conducted above 18000, or possibly had controllability issues, hence the limitation.
In any case, flying outside of the limitations is not a good idea.
It reminds me of the debate on VMC testing in twins. The higher your initial altitude, the more time you have to recover from a spin. On the other hand, the higher your initial altitude, the greater your chances of a stall/spin scenario, as opposed to just losing rudder authority. One thing for sure, if I ever get it wrong, there will be plenty of people to criticise my technique!
Juan, referring to the captain of this flight: "I believe he was even a Boeing test pilot."
I knew one of the pilots in this crash. If Juan was referring to him in the quote, I can confirm he was not a test pilot. He was a Boeing technical pilot. Boeing technical pilots develop the flight crew operating manuals; normal, supplemental, and non-normal procedures for operating Boeing airplanes; and provide airline operators the best practices when flying Boeing airplanes. Boeing technical pilots do not fly the airplane as part of their typical job responsibilities.
I do pray you guys are doing OK with all the snow. Thanks for the update, Juan.
I flew FCFs for the Air Force on a specific airframe. The Regs called for Day VMC only on initial flights. However.....it was not uncommon for "some" to push the rules waaaaaay beyond just stepping over the line. There were flights that were performed where shortly after takeoff the plane would enter a cloud deck and attempts were made to "get on top" of the cloud cover...even though the rules were again "VMC only." I've actually been on a sortie where we took off entered a cloud deck at 1000 to 2000 ft overcast in an attempt to get on top only to never get on top of the cloud deck up to 20k. The flight was cancelled and RTB. All the while the rules say "VMC only" It amazes me how some "pilots" i.e officers wish to hack the mission so much they risk not only a valuable aircraft but the crews on board as well.
Swept wing aircraft don't just stall and spin. They (in general) enter something known as a post stall gyration if held in the stall too long. Most of the time any intuitive control input just exacerbates this condition. In any event you need a lot of altitude to let the aircraft recover hense all of the altitude restrictions on the procedure. A little careful reading could have averted this.
the pilots probably knew all that. They did the stall test at the wrong time at the wrong place, is all.
@@adotintheshark4848 It is referred to as PINC. Procedural Intentional Non Compliance.
They were above altitude, not below.
Whatever happened wasn't caused by flying too low.
@@--SPQR-- they were outside of required parameters.
You said before in reading about the stall it was test pilot stuff... I'll watch now and thank you T 😎
Looking at the weather data the pressure was at 29.59
Low
There was a major weather event happen all across the W. US at this time.
There was Very Heavy snow Falling at Powderhorn ski area to the NE of the accident site where I was skiing when they went in.
RIP Pilots
Flight should have never happened then, over confidence and expectation bias.
If a required stall test is perfomed correctly,what would constitute a failed test? What is the objective of the test? Or what is the test designed to find out?
Quite. And if the objective is to verify the stuck pusher, relying on the stuck pusher, without a procedure for it's failure... Or have I misunderstood.
I believe it is more of a calibration test after major maintenance work. Making sure the aircraft does everything as according to specs. ie- the stick shaker activates when it should, the aircraft stalls when it should. You want to make sure that all is well and performing as designed before allowing a " non test " crew to fly the plane.
Stall shaker not activating
It's a verification of the aircraft systems are doing what they are designed to do after major maintenance.
I would venture a guess and say a 10' deep hole in the ground was an indication of a 'failed test!'
Super qualified or not... Test pilot stuff is still test pilot stuff. There's always that chance. RIP
In looking at the test procedures (as you showed them), I didn’t see where they defined what the criteria were to identify a passing test or what constitutes a failed test. I also noticed that one of the activities that necessitates the test was removal, adjustment or installation of the stall triggers. What if they are installed incorrectly? What if something prevents the stall warning system from pushing the stick? How long should the pilots wait before initiating recovery in the absence of a stick push? I don’t see any “if this (some action) fails, do this…” type of wording. Am I missing something?
A test procedure with out defined pass/fail criteria seems very incomplete.
Hey Juan, you talk about the air above the 18k stall test ceiling being too thin for a prompt recovery... that's probably not the primary reason for the ceiling. Having worked on stall characteristics with the Hawkers, the nature of the stall changes with Mach #, and when you get away from "low & slow", you start getting into a different type of stall phenomenon. The classic low Mach leading edge stall starts blending into more of a trailing edge stall buffet at even slightly elevated Mach. The goal of the post-maintenance stall tests is to dial in the rigging and stall strips for appropriate low speed stall behavior. You also talk about the accident pilot with plenty of experience. Not all experience is the same, and the book calls for Hawker-stall-qualified test pilots for the post-maintenance stall checks. Not just any stall-qualified pilot. Hawkers can stall poorly if not properly rigged. After Cessna took over the product line, I'm not sure how much of that culture or group of folks remains intact.
Thanks for your insightful and informative response! As a non-pilot with a meteorological background I can see that stall speed would increase with altitude.
Thanks Juan for the update!
What are the chances this indicates the aircraft systems failed the test? Is it possible the stick pusher was late or didn’t function at all, thus it became more fully developed and they were unable to recover?
Someone upthread claims the stick pusher doesn't work above 18,000 feet on this aircraft. If that's the case, being that they were 2000 feet higher than they were supposed to be according to the manual, that would have done it. Two thousand feet of altitude is more than enough to turn a stall into an unrecoverable disaster.
@@jmowreader9555- The pusher is not inhibited above FL180.
@@bradcrosier1332 I'm not sure why people are making a big deal about the shaker, it's irrelevant. Doesn't matter if it's delayed or doesn't work at all. Imagine you're sitting in the front seat and you find yourself violently shaken, like an angry dog has you by the neck, then in a fraction of a second you see the earth rapidly fill your windscreens. In that moment, if you still fail to identify a stall condition exists, you have no business being in the seat at all.
Thank you Juan.
Quite an interesting analysis - thank you sir .
Great report Juan
Wow...another scary one. Hope family and friends are doing ok. Thanks again for your efforts in keeping us safe. Looking forward to many more...we hang on your every word, and I tell my young interested friends they had better not miss one.
"The book says not above 18,000."
"It'll be alright."
"That's just there to keep the lawyers happy."
You have some details like who the PIC was that I don’t see in the 4 page NTSB report. Wondering where you get that.
I can confirm one of the pilots was a very respected and professional individual, a one time Check Captain at American Trans Air and had a very successful post airline career.
As pilots, we can be goal oriented to a fault. None of us is “invulnerable” as the FAA puts it. Our job comes with lot more risk than we want to imagine. Keep us posted Juan. We appreciate what you do and it is obvious that you do it with a lot of compassion and empathy along with the desire to teach. Thank you.
Oh crap, I hadn’t heard that. I’m saddened by the loss of any crew, but as a former TZ warrior, it’s doubly sad to hear of the loss of one of our own. I can’t figure out how to contact you offline, here, and I won’t ask you to reveal the name publicly out of respect, but perhaps if you have an old seniority list you could post an employee number (IIRC they were on there). Thank you, and I hope all is well with you. BC - 105531
That video of a Hawker crew doing a stall test, then entering a secondary stall sends shivers down my spine. I would figure that by the time the crew started pulling back they had achieved adequate air speed, not so. Maybe stick to a Citation.
Airspeed is irrelevant to stalls, it's only used as a proxy for AOA in aircraft lacking an AOA vane. "Accelerated stall" is your search term for today.
Well, it's not _entirely_ irrelevant to stalls... if you have enough airspeed you'll exceed the G-limits of the plane (or the pilot) before you stall ;-)
The scab Clay Lacy? The name that never goes away...
The "Effing Scab" Neal. Gotta get your nomenclature right! ;)
Yep, old Clay Lacy is a genuine POS. I always wanted to barf every time I opened ProPilot to see he and Murray Smith jerking each other off about what great guys they each were.
Lol, you ladies jealous
The guy that pioneered business aviation whose company has survived every recession and employees many many hundreds of people and supports multiple charities and aviation education... With hundreds of millions of dollars of managed aircraft.... What have you done since? Grow up.
Well, we didn't cross a picket line.@@rcbturbine9
Thank you very much for the Update! That´s a really dangerous Testing. RIP to both Pilots. My condolences to their families and friends.
At least they passed operating their PASSION!
I’m curious as to why there’s an 18,000 foot MSL limit on the stall testing procedures? I believe density altitude would come in to play. A cold day versus a warm day scenario would probably affect the stall testing outcome. Anything above 18,000 feet is positive control airspace. Perhaps that’s another consideration with the limitation in conducting the test.
tendency to roll to be corrected by aileron. that's sure different from a small plane. we're taught to use rudder.
I'm confused. A test is required to validate the maintenance done on the leading edge. Assuming the test has a "passed," condition, what would be considered a fail?
Probably aircraft stalls before the stick shaker/pusher activates??
@@spoonmanTX My thought also... so if the stall warning they were testing was inoperative, they would enter a full stall w/o getting the pusher?
@@tim1398they should still be able to recover, no? The tape he showed looked very violent at the stall
No stick pusher or stall warning within published limits = fail
Stick pusher and stall warning within published limits = pass
Spin after stall = screw the pooch
generation of NTSB paperwork is a hard fail...
Was there on the wreck haul, RIP.
As swept wing jets have 'sporty' stall characteristics as Juan says, I'm amazed AF477 (which was stalled form 42,000 feet all the way to the impact with the ocean) remained stabilised in deep stall and did not roll off into a spin.
just to be sure since your phrasing is ambiguous: while AF447 was deeply stalled, it wasn't experiencing "deep stall", the distinction being that in a true deep-stall the plane stabilizes at high AoA despite pitch-down input from the pilots whereas AF447 was actively being held at AoA by pitch-up input from the pilots. In either case however it's an interesting question. The first known true deep stall (BAC 1-11 G-ASHG) also crashed straight into the ground with wings level, in that case the pilot even _tried_ to roll and yaw the plane in an attempt to escape the deep stall.
It does make some sense to me that spin tendency should be reduced at increasing AoA. At the moment you're _just_ entering stall the wing experiences a very rapid decrease in lift which is very sensitive to increasing AoA and any minor thing that might disturb the flow, so typically you end up with one with stalling slightly sooner and substantial lift asymmetry, inducing a bank and subsequent yaw that reinforce the asymmetry. However, at high enough AoA the lift index will begin to level out towards zero hence so will lift asymmetry, so I'd expect this spin-inducing effect to diminish or disappear. Instead the aerodynamics are increasingly dominated by drag rather than lift so you kinda have to do stability analysis from scratch, and it's easy to imagine this drag could induce positive roll-stability and directional stability in a plane with swept-back wings and positive dihedral (but imagination is not a substitute for computational fluid dynamics or wind tunnel testing ;-).
The term “deep stall” is very often misused even by Pilots. You can’t be in a ‘deep stall’ unless the aircraft has a T-Tail or, in some, cruciform tail ones. The reason is that the main wing, in high AoA conditions, at some point will ‘blank’ the T or CF tail and hence the term ‘deep stall’.
So, the A330, which the AF447 was, could have NEVER entered a ‘deep stall’ because it can’t by design😉
@@user-kb8gh5jv9t The term may also be more generally applied to other examples of planes that at very high AoA can enter a _stable_ mode where the plane is deeply stalled and there's insufficient pitch authority to overcome the stability of this mode and return the plane to normal flight.
@@MatthijsvanDuin , incorrect, simple!
@@user-kb8gh5jv9t I disagree. What you describe is ONE form of deep stall, better described as 'unrecoverable' stall. AF447 was at such a high AoA that recovery, if it had been attempted, would have been very prolonged and taken tens of thousands of feet. That is recoverable if you have the height, but is also a deep stall, unlike a shallow stall when simply pushing the stick forward and adding power will give a near-instant recovery.
Imagine your car, having a break pad replace and you have to test it by running towards a cliff and hit the break to confirm the break is functioning properly. I buy a new car. A different car.
Fine line...
I noticed the FL180 thing in the first brush at this. If they are above FL180 or 18000 MSL, they are automatically IFR. I'm not seeing any actual meteo condition that says IFR. I seem to remember a Challenger accident where the crew decided to be test pilots for fun and they zoom climbed to the aircraft's service ceiling and stalled into an unrecoverable position
Solid content
Thank you very much for the Update! That seems to be s really weird Test.
RIP to both Pilots. A really sad story.
Thanks!
Second one of the “family members” you’ve covered in the past couple months. Not what we like to see. Always hate to see a Hawker go down. Great vid as always!
They were DH-125s back when I was a lineboy. I don't know s--t from biscuits about it's evolution, I remember the weeping leading edges for ice though.
Question: Why does the weather radar need to be on standby when doing this stall check? Is that just so any hard maneuver doesn’t damage the radar?
Thanx Juan ! Another situation were people are in a hurry ! It’s crazy that all these parameters have to be met when stalling this aircraft ! I believe that this aircraft is to unforgiving just because of the parameters listed before attempting a stall ! It’s so sad that all this flight experience had to go down like this !
It seems incredible that routine periodic maintenance requires a flight check that, if a problem is found, leads to a significant chance of loss of life and, it appears, even if a problem isn't found can kill even the most experienced test pilot.
This test has been done thousands of times and does not pose a significant chance of loss of life. If the aircraft fails the test and one wing stalls first some adjustments are made and the test is done again. In the early 2000s I sat jump seat during these tests several times on a hawker 800 I maintained. Even when it failed the the test, recovery was easy. The pilots were 2000 feet above the flight envelope for the test, what other parameters were they outside of? Complacency is most likely what killed the pilots.
@@davidr8309 Interesting. Thank you. Is the suggestion that the root cause was that this test was done in air that was too thin for a high probability of safe recovery? Or is it that this is not a causal factor but something indicative of complacency which led them to undertake other unknown but unsafe actions. If it is the former then perhaps the safe height needs to be lowered or the criticality of that ceiling (re-)emphasised. If it was the latter then it would be good to know what those additional unsafe actions were.
Unless the NTSB finds something suggesting there is a problem with the published test
An innocent question: When they do these tests, do they HAVE to be done really close to the airport or could you, say, fly from Colorado to California to do them? The requirements for this test - minimum 10k AGL, minimum 10k above clouds and maximum 18k MSL - don't leave you much wiggle room in February when you're in the Rockies. To me those numbers scream "fly this bird to the Mojave Desert and do it there!"
The issue is, if the test was unsatisfactory, you’d need to return to the maintenance facility, hence you’d prefer to not be three states away if possible.
Do all TKS equipped aircraft require stalls post maintenance?
Oh my. You just never know.
Is there a chance some thing mechanical caused the “stall test failure?” Thanks
Used to operate an 800XP
Hated doing this test
Juan...no snow report....is everything "ok" at Global World Headquarters?! I rode in a Hawker in 1986...I am so glad my company moved to the Cessna Conquest and a Citation IV in 1995 on which I had many happy flights!
Only 6" of snow here! About 10 ' over the summit.
@@blancolirio good, I had fun watching all the RUclipsrs showing the snow...Holy Cow! CAVU here a KRDU! Full Pool for 2024 in Juan's World!
@@blancolirio
Aruba anyone!?
Thank you Juan.
RIP these pilots...went beyond sticker shake to out of control quickly.
These pilots were extremely experienced maybe too confident ?
All it takes is one slip. I am 75 and just sold my motorbike. Since sustaining a concussion 2 years ago when a large buck jumped onto me and my Honda things havent been quite right with my perception and vision. After leaving the bike in my basement all this time I finally decided to sell it and keep only the memories. I learned to fly a Cessna 150 at 21. I cant imagine being in control of a plane now. Slip ups at altitude are not forgiving.
Is there any non-military commercial aircraft with automated spin recovery?
This is gonna seem like an off-the-wall kinda question, but the curiosity got to me, so I will ask: Could the stall system stick shaker-pusher system go wild once it is activated (as to not turn off once critical AoA is breached). On the pusher, how many pounds of push (forward) are involved. I think on the B727 it was 50 pounds of push forward on "pusher". I assume there is a CB for the stick shaker-pusher? Just wondering here.
The Hawkers have a hydraulic pusher, and it's supposed to be sufficiently compelling to not be overridden. IIRC, it's like 60-ish lb, so one pilot could certainly overcome it if his life depended on it, and 2 pilots together unable to override it is pretty unlikely. That said, the flight path into the ground is clearly a spiral, not a straight dive, suggesting a roll-off.
Respect to the people that haf to listen to the cvr
Would a ballistic parachute help in such spins ?
I've heard that Lear requires that a factory test pilot perform this test on their planes.
There was a cadre of us that stalled the Mark II wing 20 series Lears. Stalled many of them, but I was trained and lived to tell about it
@8:23 at the bottom of 57-41-00. I wonder if 27-33-00, 501 was complied with prior to the flight? Imagine waiting for the stick pusher to do its thing and it doesn’t.
Of course it was 🤡
@@FrailRider must be a coincidence that STS is trying so hard to fill some sudden openings at Weststar
Ultimately it doesn't matter if the stick shaker works or not, nobody is ever going to misidentify a stall condition in this aircraft. If the shaker fails, it'll be instantly obvious.
@@nohandleleft besides, it’s what was being tested… kind of goes with out saying. They weren’t making sure the aircraft still stalls lol
Hello there, Juan. I’m in greater Nashville area and a plane crashed on I-40 in the area of town I grew up in. When there are more details/you have a chance, can you give us some info on it?
Hey blanco are you able to do a video of the Apache helicopter crash back the weekend before last just outside of Tupelo Ms. Two guardsman were tragically killed doing a training mission and it was so aweful. It’s just 30 miles north of my little city. Wondering if any info on what happened.
It would be interesting to see that secondary stall after recovering from the first, from the outside.
When testing the safety feature is deadly. And this isn't an insulated isodent.
it's not a ocmmon cocurrence, either.
@@Milkmans_Son I'm aware of 2 or 3 in the last year or so, and I'm a casual observer.
Juan, thank you 🙏
Do you know the flight crew names?
I think CFBWH is the plane that crashed near I40 Nashville TN a few hrs ago
👍 JUAN BROWN 👍
What if maintenance of the leading edge was not done properly?
You can have ticks and fleas. What other mechanical/systems failure could be involved here, that might interact with the stall testing to make things worse?
Hey Juan just wondering are big Airliners Boeing ,Airbus need this kind of maintenance and then flight tested into a stall ,do you normal line pilots ever have to test fly a plane after heavy maintenance has been completed .Curious Aussie
Kym
Adelaide
I flew for United and line pilots never ever did test flights. United had its own test pilot division and they would do any required test flights.
@@tbyrde53
Thanks Mate appreciate the input always wondered who tested the aircraft after major repairs stressful job I would imagine
It does beg the question. If a post maintenance stall test is in a dangerous corner of the flight envelope, such that an experienced pilot could get themselves in trouble, is there any other way to test the system? Do other aircraft undergo a similar test when work is performed on the leading edge?
Looks like they went to 20,000' to meet the requirement of 10,000' above cloud but ignored the 18,000' maximum in doing so.
It seems clear that they didn't strictly follow the procedure. But practically speaking would that make a difference? What if the cloud ceiling was 8,000' instead of 10,000'?
@@philhyde983 exactly what i am wondering as well. what are the dangers of performing the test higher than the procedure mandates? the only thing i can guess is that a spin that is entered in higher altitudes can be so violent that even when the aircraft loses a significant amount of altitude _afterward_ the characteristics of the spin are still more violent than one started *at* that altitude. if that makes sense.
Yep. Ignored a very important parameter, put there for a reason. Thinner air up there.
@@shodancat1000Yep, he covered that in the video: Thinner air plus swept wing = less ability to recover rapidly.
By the time they hit thicker air, the aircraft was already in an irrecoverable spin.
@@philhyde983Then they'd havre started the procedure 2,000' lower & within the specified parameters, where the thicker air makes the stall less severe & recovery easier.
Juan, I'm not a pilot but I am very interested in aviation and I'm puzzled as to how an aircraft can stall in a nose down attitude. Could you explain how and why that can happen? I always thought that the way to get out of a stall was to push the nose down to get airspeed and generate lift on the wings.
@broncolirio there was a single engine airplane that crashed in Nashville on March 3.
I don't understand why these flight tests were done in weather where clouds were around. The times I have been caught up in flight tests as a 'dead weight' it was all done on perfect clear days over the water off Sydney.
The Aviation industry (Military & Commercial) general has become so "Risk Averse" we have been crippled by policy. Corporate Board Rooms and Government Desk Jockeys have no place setting procedure in the Cockpit. Minimum requirements are driven by Shareholder profits and Regulations over Customer Satisfaction and Safety. Sad. Thanks sir. We appreciate the info always.
Can someone please describe further what was being tested? What would a failed test have looked like? Couldn’t that be the issue here??
There have been so many stall test failures in the last few months is there another way to do these?? Im not a pilot. But are these type of scenarios going on everyday??
A SE plane crashed on I-40 in Nashville, TN. Near John Tune Airport. It has been in the news with typical type coverage. A lot of traffic approaching John Tune from the West roughly follows I-40 (and is visible from my home, just South of I-40). I hope you can cover this accident.
Fate is still the Hunter.
I will be curious to see if they can determine if fuel was in the ventral tank.
Being experienced in type is not the same thing as being trained to recover from the multitude of ways this test can go sideways if something was not put back together right.
What does it feel like when the stick pusher fails to engage for example? Is the pilot just supposed to keep pulling until they’re dead? That test procedure is written under the assumption that the very thing they are operationally testing is going to work as designed with no guidance at all on how to recognize that it’s not working.
Hawker is going to lose the inevitable wrongful death lawsuit badly and they deserve to for sending line pilots out for a high risk test flight with so little guidance or training.
Great points. Hope we get answers and clarity.
Excellent point. I flew to the stick shaker in the jet and then recovered. No big deal. Later in the Sim I was instructed to allow the stick pusher to do it's thing without any resistance until the jet was flying. But, that was a SIM. Were I in the jet I may have flown it right into the ground while waiting for the pusher to save my ass. How is a line slob supposed to know? I know now that I won't intentionally FULL stall the jet unless I am flying with Johnny Wad next to me and he's gettin' my learn on.
This is what I was thinking. Even after running tests on the ground, it still seems much too dangerous to require such a test of a vital system because of what happens if it DOESN'T work.
Yep and Hawkers lawyers will point out they were above the specified altitude and the case will be thrown out.
Not good points, and zero understanding of how and why the test is performed.
BTW, I saw you commenting on Ward Carroll's channel.
I really thought ailerons were not to be used during stalls. It does seem strange that this calls for them to be used.
As you approach a stall you need to use the ailerons to keep the wings level. If one wing stalls more it will drop and become a spin. When you are in a spin you want to keep the ailerons level during the recovery.
How will they know if the work was done correctly?
Juan, very difficult stall characteristics on this plane! I was shocked seeing the footage from inside the plane. “Approach the stall with power off and no more than 1 kt per second” tells me the factory is warning us this will be a handful. How do your Boeings (which of course have swept wings) react to a stall??
Im not a pilot. Would density altitude have anything to do with the 2000 foot difference? Is there such a thing that high up? I assume its all pretty cold up that high
Density altitude is simply a way of referencing how dense the air is for aerodynamic purposes. Yes, compared to sea level, it’s very cold at 20,000 - however, from performance and aerodynamic standpoint, if the air is ten degrees warmer than standard atmosphere, the the density altitude (effective altitude, if you will) is going to be significantly higher than 20,000, at ISA +10 (which is very common) for example, the density altitude will be approximately 21,170 feet.
My only experience is in light, single engine aircraft. Why is there a requirement that the weather radar be on standby for this test?