Flap Retraction/Extension Schedule B737
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- Опубликовано: 3 окт 2020
- B737 Flaps extension/retraction schedule is covered in this video in detail. both what is mentioned in the FCOM, FCTM, and QRH along with some personal techniques.
Hope you find it useful.
Let me know if you have any questions or comments.
All the best
Abdul
![What Does An Airline Pilot Check During Flap Retraction? - [Boeing 737 Take-off]](http://i.ytimg.com/vi/26jxvEX44CI/mqdefault.jpg)
![What Does An Airline Pilot Check During Flap Retraction? - [Boeing 737 Take-off]](/img/tr.png)
Really well done! Super informative. Information not found in most other similar tutorials. Thanks
Thank you for your kind words H Donner
Great video! I really like the content on your channel!
Thank you Emerson,
I appreciate your kind words.
All the best
Abdul
Hello Abdulmuati I'm Soham from India and I'm a 737 researcher..............great video......
Thank you Soham 🙏🏼
Thank you so much! I learned a lot. Very good instruction.
Well, here goes my answer. Thank you so much captain!
You are welcome Erfan,
I believe we all need to be open minded, I try still to keep an open mind regarding this issue along with other things, but so far I am not aware of a reason to use them. (F2,10, &25)
But I will keep an open mind, if any body can logically or procedurally state otherwise.
All the best
Abdul
Thanks for sharing the video Capt. Abdulmuati , regarding your question at 1:41 minutes. Newer B738 aircraft models have the white bug at 80kts while the older 738 models have the white bug at 100kts.
Whether 80kts version or 100 knots version, it indicates the following:
• Displayed automatically during preflight
• Removed at first flap retraction or when VREF is entered.
Keep up the amazing working. Cheers from Egypt :)
Thank you zackzeko,
Appreciate the answer. 🙏🏼
100 knots airspeed bug (white)
Indicates 100 knots:
displayed automatically during preflight
removed at first flap retraction or when VREF is entered
737 flight crew operational manual PFD/ND-displays
Hi thanks for sharing this video. A couple of things to add to what u mentioned in the video: normally when u takeoff with the VNAV armed - in order to be able to do that the FMC software must be 10.8 version or later, a valid flight plan and valid perf data must be entered in the FMC, and both FD’s must be armed - at 84kts the autothrottle will transition from N1 to THR HOLD until 800ft afe when the autothrottle will transition to ARM until reaching the THRUST REDUCTION HT entered in the TAKEOFF REF page 2 at which point it will go in CLIMB as indicated on the thrust panel - in your case it did not transition, not sure why. At 400ft agl the VNAV will go from a pitch command ensuring a positive rate of at least 200fpm to VNAV SPD adjusting the pitch to achieve and maintain the V2 manually entered on the MCP+20kts. At the programmed ACC HT of normally 1000ft agl, the AFCS will adjust the pitch for 230kts or for the speed for the active SID whichever is lower, allowing the airplane to accelerate and the flaps to be retracted on schedule. As the flaps are fully retracted and the IN TRANSIT light is out the AFCS will command a pitch change to maintain the preprogrammed climb speed of normally 250kts or the speed for the SID whichever is lower.
With the first flap retraction the minimum maneuvering speed computed based on aoa and velocity is shown on the PFD - the top of the amber band provides full maneuver capability - 40 degrees of bank (25 + 15 excursion) corresponding to a load factor n of 1.3g - 1/cos bank=1/cos40 - and providing a margin over the Vs1g or stall speed 1g of 1.14 or 14% - Vsn=square root of n derived from the Lift equation solved for Vs1g and considering that L must equal weight, the Lift to Drag ratio must be 1. At speeds lower than the minimum maneuver speed the maneuverability in terms of bank angle, g’s and stall speed margin decreases. The speed in the middle of the amber band provides adequate maneuver capability - 30 degrees of bank (15+15 overshoot) corresponding to a load factor of 1.15g - 1/cos30 - providing a margin over the Vs1g of 1.07 or 7% - Vs=square root of n.
The bottom of the amber band corresponds to the speed at which the stick shaker will activate.
Flap maneuver speeds whereas are based on Vs1g and they are computed based on weight only providing a margin over Vref for flaps 40 which for airplanes certified under Part 25 equals 1.23Vs1g. As matter of fact the heavier the airplane, the greater the AOA/Cl needed to generate the lift required to balance the weight, the lower the margin over the critical AOA and thus the higher the stall speed as revealed by the lift equation solved for Vs - Vs=square root of W over 1/2 Clmax S d - being L equal to W during straight and level unaccelerated flight, and thus Vs=square root of W. While operating at the flap maneuver speed full maneuver capability of 40 degrees of bank - 25 + 15 excursion is guaranteed providing a certain margin 14% over the Vs1g stall speed at a 40 degree flap setting - 1/cos 40 = 1/0.77 = 1.3g’s thus Vsn=square root of 1.3=1.14 or a 14% margin over Vs1g.
Thank you Diego 🙏🏼
For the clarification
Wow did you type that ? Such indepth knowledge is rare nowdays. I AM A 737 pilot (newly type rated) I Have a few questions regarding automation.Can I connect with you please. I will be really grateful.
I really don't have anyone to clear my doubts.
THANKS FOR YOUR INFORMATION CAPT.
You are most welcome Farhad 🙏🏼
Thank you so helpful!
🙏🏼
Excellent captain 🙏
Thank you 😊
Indonesia, just wad im loookig for. Thank you
You are most welcome
All the best 🙏🏼
great video as always Captain! if possible i’d like to request for a video on manual flying and manual thrust control on the 737 during idle descent, pitch anticipation during flaps extension until intercepting the approach until landing while maintaining the profile at the same time. thank you in advance Captain safe flt always 👍
Hello Rukawa,
That is a great topic to cover, thanks for the suggestion.
All the best,
Abdul
Capt It would have been more better doing a G/A too.Nice video.Hope u will do a G/A video shortly ,especially ,what is difference between G/A ,and N1 in thrust FMA and wn will GA annunciation comes on ND and all.
Hello arun
Thx for the suggestion will as that to the list.
Yes a G/A video 2 Eng and G/A single Eng
Thanks for the video.
A question, does the FMC sequence automatically to the Flaps Up speed or do I need to specify the speed in the legs page as a speed restriction.
Hello Selman,
Yes the FMC will sequence automatically to flaps up speed at the acceleration height you enter in the FMC preflight usually 1000ft
You will need to enter the speed in the legs page if you have a speed restriction only.
There is Vref +15 or Vref+20 white bug displayed with selection of VREF.When do we use this speed , what is the purpose of it? I would appreciate if you could explain it.
Hello Aylin,
That is going to be Vref for Flaps 15 landing,
DISCLAIMER: the following is just a personal opinion.
A scenario that you might use this is if you are already fully configured for landing (F30) then you got an Eng failure, you can ask for F15 and use the white bug as your new Vref, and continue the landing. Assuming of course that you don’t see any reason to prevent continuing the landing.
It might not be a good idea to do a G/A if you lose an Eng at that portion of the approach, but just to continue and land.
Hope that help
Abdul
Thank you sir🙏🏻
What is the difference between Flaps Up and Flaps 1? Does Flap Up simply just mean that the flap is not extended at all?
That is correct Jeppe Andersen
👍🏼
Thank you, Captain. I see you use VNAV before cleaning up the aircraft. I was under the impression that VNAV was to be engaged only after bug up speed was reached and all flaps and leading edge devices were in the UP position. Or is this a company SOP? Best regards.
You are welcome,
VNAV use before Takeoff “Arming it that is” or engaging it after cleaning up the airplane depends of the FMC version installed in the airplane.
Old versions you should not engage it till after cleaning up
Newer version you can arm it before takeoff,
Hope that answer your question
@@AbdulmuatiAsiri37 Thank you for your explanation. Can you tell from which particular version on VNAV can be used like this?
@@AbdulmuatiAsiri37 Thank you for your explanation. Can you tell from which particular version on VNAV can be used like this?
Am familiar with two versions 10.7 did not allow for VNAV to be engaged prior to flaps retraction,
The latest version is 13 which does.
A better way to know weather you can engage VNAV prior to flaps retraction or not is by checking the FCOM Vol.1 Takeoff procedure profile and you can be certain whether you can or can’t for the specific airplane you are flying.
Hope that answer your question, let me know if you have any other questions,
All the best
Abdul
Excellent information, thanks for your insight!
Thank you Bill for taking the time to write those kind words.
Really appreciate it 🙏🏼
You are most welcome. Retired US 121 Captain, never flew this model ( flew -100/200/300). Did fly 757/767, but that was 15 years ago. Just getting into flight simming, struggling with lack of computer knowledge. Watched several streamers, but your video by far most accurate and insightful info that I wanted to know. Very professional, very good information. Thanks again for taking time and effort to properly educate us,
Hello Bill,
Am glad that a fellow pilot find these videos helpful, hang in their with the technology, some times it get frustrating to setup the the thing right, but with patience it works,
Please do share your knowledge by commenting on the videos, like how did you use to do it or any tips or techniques, am sure it can help other pilots.
Thanks again
Abdul
The Manuals say: When approaching and before decelerating below. Many pilots use the flap placard speeds to lower the flaps. Personally, I don't use the flaps as speed brakes. I always start lowering the flaps, below 230 knots. The placard indicates the limits and normally we don't operate at the limits.
I strongly agree with you Osvaldo, you are absolutely right, the speed limit is a limit, not a reference to trigger flaps extension specially flaps 1
Thanks for the feedback
@@AbdulmuatiAsiri37 There's something else that I would like to mention: When you ask"Gear Down, Flaps 15, " 99 percent of 737 pilots put flaps 15 without verifying that the Gear is Down and showing 3 green lights . It's the manufacturer's recommendation but nobody cares, because most of the time, we don't have a gear problem. The day the gear has a problem, the horn will sound and we will be burning fuel with flaps 15 while dealing with the checklist.