737 Landing Gear

A detailed description and history of the landing gear on all generations of the Boeing 737.
0:00 Intro
1:01 - Main landing gear components
4:11 - Shimmy
10:02 - Doors
11:42 - Gear seals
23:37 - Downlock viewers
26:51 - Manual Extension
32:36 - Nose landing gear components
33:38 - Steering
44:19 - Wheels
47:00 - Tires
55:00 - Brakes
1:01:31 - Accumulator
1:07:16 - Anti-skid
1:09:46 - Autobrakes
1:13:21 - Panels

[@akashoa7929]

Thanhs Chris , Imagine 7 Hours sitting and watching your valuable slides and videos .Brilliant

[@ChrisBrady737]

Wow, you have an amazing attention span! I am glad you thought that the time was well spent.

[@RedEye737]

Finally being able to see what the locks/sensors look and function like is amazing. Incredible video, as always, Captain. Learning something new everyday. Even though I am just having a pleasure of doing this in a flight simulator environment, I find this information invaluable. 737 is a bird that I love and want to know more and more of. I'll be checking out the quizzes on your website.

[@ChrisBrady737]

Great to hear that you are enjoying the videos

[@sasmsamy962]

Great job as usual. This episode has a number of "tips" for us on the line that make it even more useful and actually distinguish these presentation from others. Thank you Chris !

[@ChrisBrady737]

Thanks very much for your kind comments. Please tell your colleagues about the videos

[@christiaankruger5299]

Man, Chris these videos are great. Wish I had them prior to doing my TR. Thanks a million for going to the effort.

[@ChrisBrady737]

My pleasure, thanks for your kind words

[@Gorvaunity]

With a little luck, I'll be transitioning from the E190 to the B737 in some time. Your videos are incredibly helpful, and make for a great addition to your website. Thank you for taking the time to share your knowledge.

[@ChrisBrady737]

It is my pleasure to help. Best of luck with your type conversion

[@omidtorkzadeh2487]

Hello captain Brady, I'd like to thank you for such incredible job, I'm an AME from Canada and found your 737 thechnical channel very practical, provides more detailed and accurate materials than the type course I've taken. It'd be great if you could also create the same technical channel for other Boeing products.

[@ChrisBrady737]

Hi Omid, thank you for your kind comments. Unfortunately I am a 737 specialist and would not have the necessary knowledge to do the same series for other types.

[@omidtorkzadeh2487]

@@ChrisBrady737 I understand but I'm sure if you did, it'd be the best one, thanks again.

[@arthurgord]

Same thing here. I'm currently on an NG course. Watching your videos after classes

[@allandunne2150]

Hi Chris, the nit picker again (I'm really sorry about this, please tell me to bugger off if too irritating!!), at about minute 52:10 you mention the aquaplaning formula and say "8.6 times the square root of the speed" instead of tyre pressure, easy to do when eyeballing all those numbers in the table! Great presentation again, lots of interesting and useful info.

[@ChrisBrady737]

Hi Allan, no problem pointing out these errors. At least I got the formula right in the calculations!

[@soumyadeephait70]

Thank you Captain. 🙏 These videos are immensely helpful for its required purpose.

[@ChrisBrady737]

Glad you like them!

[@yanwan-kf8ph]

Thank you for making this incredible video about 737, that helps me a lot !!

[@ChrisBrady737]

My pleasure, thanks for watching

[@ElfoRomagnolo]

Thanks Captain, really valuable and appreciated info,explained in a very clear and understandable way, thanks again for sharing a bit of your knowledge!

[@ChrisBrady737]

My pleasure, glad you found it helpful 👍

[@tjutjutube]

Very helpful to complete the job, thank you Captain Chris

[@ChrisBrady737]

My pleasure, thanks for watching

[@IftimeAdrian90]

Good morning, great video as always, many thanks for putting everything together in such a detailed manner. An insight from the field, the tyre damage pin is also referred to as a frangible cartridge and those bastards presents with leaks every now and then.

[@ChrisBrady737]

Good info, thanks for sharing 👍

[@kijetikimavi]

Absolutely amazing videos.. this is shared treasure knowledge.. thank you for your extraordinary dedication.

[@ChrisBrady737]

You are very welcome, glad they are useful.

[@OsagieFrankIgbinovia]

Great Videos. Thanks for the information Chris.

[@ChrisBrady737]

My pleasure, thanks for watching.

[@jaspreetsinghthind5862]

Hello Capt.. I highly appreciate the amount of dedication and hard work you have put into making these amazingly informative videos. I was flying B737 NG for almost 15 years and now flying max 8. In this video you have mentioned about identifying the type of braking system by looking into the performance Dispatch or inflight. 737-8 LEAP-1B27 KG C M FAA CATB TO1-10% TO2-20% AOA-DIAL. As per your explanation this category of braking is steel ( CAT B ). But somewhere in the video you mentioned that all the max family only has carbon brakes. Please help me with this one Capt. Once again thanks a lot for sharing your knowledge and experience.

[@ChrisBrady737]

I thought that carbon brakes were standard on the MAX. The standard options are Collins or Safran Carbon or High Capacity Carbon brakes (4 combinations). It is possible that an airline has specified steel brakes.

[@jaspreetsinghthind5862]

Thanks a lot Captain.. confirmed the same with an AME too.. once again thanks a lot.

[@AwtaMadik]

Great video. I feel like The Nose landing gear tires can definitely overheat if the bearings get super hot. I've seen a RV bearing seize up and it caused the tire to get so hot it was smoking and blewout while I was trying to jack it up on the side of the hwy.

[@ChrisBrady737]

True, fortunately the nose wheel does not have brakes to add to any heat generated.

[@nicolaslutun6361]

Very interesting as usual, thank you Chris

[@ChrisBrady737]

Thanks Nicolas, glad you enjoyed it

[@CarlosEduardo-ys3cw]

Great video!!! This kind of class that help us a better understanding the technical functions of some devices. One question; are there bronze bushing along Outer Cylinder shelter and the Piston?

[@ChrisBrady737]

Thank you for your kind comments. Unfortunately I do not know if there are bronze brushings.

[@miserycat4744]

Hi Chris, Thank you so much for your videos - extremely helpful! Not sure if you're still checking these videos for comments, but if you are: can you please explain the function of the walking beam? What problem is it solving, exactly?

[@ChrisBrady737]

I thought I covered it in the video, maybe it was the landing gear tour video I described it in? Anyway, the walking beam just provides a lever/mechanical advantage to the MLG actuator when the gear cycles, this gives less load on the fuselage.

[@telescope64]

Yet again a really thorough explanation of the system,many thanks Chris,this is really useful stuff. Dumb engineers question but,if a pilot did try to rengage autobrake after first disengaging it on roll out,what would happen if he accidently selected RTO maybe due to a bumpy runway? NB:On engineer EGR procedures they always seem to ask for the antiskid switch ,if fitted,to be selected off,which I always assumed was in case during a high pwr run the a/c jumped chocks and slithered against the brakes,you wouldn't want a chance of antiskid releasing brake pressure due to a 'skid'. Maybe pilots may get a similar problem eg in heavy snow,Saab cars use to have an antiskid off switch to aid snow plough breaking,which apparently isn't helped by anti skid Best wishes from Paul

[@ChrisBrady737]

Hi Paul, Glad you liked the video and thanks for the photos! The criteria for arming and activation of RTO mode should prevent it from being accidentally activated during the landing roll. To arm RTO wheel speed must be less than 60 knots and RTO will not activate below 90 knots so it is impossible to activate on landing. Chris

[@TheCapmorei]

Great video!! great material.

[@ChrisBrady737]

Thank you

[@hyde3735]

Ty! This is an excellent supplement for me!

[@ChrisBrady737]

Great to hear!

[@philipcollura2669]

The landing gear knob appears to me to replicate the MLG tire tread. I wonder if it was an engineer's attempt at humor. Also, I read years ago that the pilots on the B-17 prototype confused the gear and flaps handles. Round knob was put on the gear handle, and it stuck to this day.

[@ChrisBrady737]

All airliners landing gear knobs are shaped like a wheel and flap levers are shaped like flaps to help avoid confusion in the heat of the moment.

[@mwdomingues]

Hi Chris. I cannot thank you enough for your videos, and I have a question (which may be a stupid one) regarding the Brake Cooling Schedule that I think you are the best person to answer since I haven't got a definite answer yet: For a subsequent take-off from a short-field landing, quick turn-around, and long taxi in and back, how can you protect against a brake overheat after an RTO if you are planning to use the inflight gear down cooling only? I mean, if you reject the take-off you will not get airborne and will not cool the brakes for the time recommended by the inflight gear down cooling. Therefore, in my understanding, they can never substitute each other, and the combination of GROUND COOLING + INFLIGHT GEAR DOWN COOLING consists in the Brake Cooling Schedule (and that's why it's called "Schedule" and not "Time" since it is the schedule of two different cooling methods), and that is why the FCTM refers to the inflight gear down cooling as ADDITIONAL. Please let me know if this rationale is correct or not. Thank you very much for all of your work!

[@ChrisBrady737]

Best place to ask that question would be The 737 Technical Group here: facebook.com/groups/737tech

[@beckydoesit9331]

Landing gear has made me rich. I was in aircraft maintenance for years and understand how all the components work. We had one bird where the front landing gear were just fixed in the down position. It refused to retract into the aircraft. I never really understood why, but who's going to notice at 30,000 feet?

[@ChrisBrady737]

I think the pilots might notice all that extra noise and fuel burn. Strange failure though.

[@Ashkan-k2o]

Nice information captain, like always, but a thing that at 40 minutes from beginning of this video that you talk about LDGT unit which one of condition is ENG NO 01 --- N2 below 56% for classic, am I right? because on video wrote and said N1 below 56% for classic. best regards.

[@ChrisBrady737]

It is N2

[@Ashkan-k2o]

@@ChrisBrady737 I know is N2 but in your video mentioned N1 sir, any how so many thanks I used to much...

[@antoineyu2810]

Dear sir, First, thank you very much for your amazing video. I have a question regarding the NNC "landing gear lever jammed in the UP position". After trying to move the lever down with the override trigger, if that doesn't work, the QRH asks us to check that the nose wheel steering switch is in the NORM position because the use of the alternate nose wheel steering might retract the gear on the ground. I was trying to figure out why but i couldn't find any information in my company manuals and FCTM. Thank you very much for your answer, Antoine

[@ChrisBrady737]

That is because when you move the alternate nose wheel steering switch to the alternate position, the landing gear transfer valve moves to the alternate position. The landing gear transfer valve moves the pressure source, for the landing gear retraction and the nose wheel steering, from hydraulic system A to hydraulic system B. If the lever is in the UP position introducing system B may cause the gear to retract.

[@KhurrammalicK123]

Excellent

[@ChrisBrady737]

Thanks for watching

[@alphapilot1908]

Might sound silly, but what is an overcentered lock/mechanism, and how does it help?

[@ChrisBrady737]

The overcenter mechanism keeps the gear locked down. It requires an actuator to break the lock by pushing the mechanism back through the centre position, allowing the gear to retract.

[@alphapilot1908]

Thank you for the prompt response. Just finished watching the video. Lovely content as always

[@louisanderson6375]

@ Boeing 737 Technical Channel: Love your vids! I have a question: If the Ldg Gear Control Lever (on a B737NG) was left in the "UP" position in flight and the flight crew forgot to move it to the "OFF" position, would there be any adverse effect(s)? Ie: Any hydraulic sys A issues as a result of the Ldg Gear Control Lever remaining in the UP position? Thanks!

[@ChrisBrady737]

There shouldn't be any major effects, possibly just a degradation in system life. The OFF position removes hydraulic pressure from the LG system.

[@captainwoodworking1273]

Hello Chris, one question when you talking about the down lock sensor that there are 2 each gear strut, dose that mean that each sensor is connected to a different light in the cockpit? Like one on the main gear light panel and one on the overhead? Thanks in advance

[@ChrisBrady737]

Good question, the answer is that it all depends! If the aircraft has had SB 737-32A1343 then yes, if not then no. By no I mean that either PSEU system (1 or 2) can operate the primary and aux LG lights. Check out my PSEU video for more details on the system 1 & 2.

[@DL14204]

Good stuff! Question. I apologize for such elementary questions. But, with the shut down of No2 Engine and obvious loss the Hyd B EDP, does/can the Hyd B EMDP still power the Autobrake and make it available for landing?

[@ChrisBrady737]

Yes, hence its inclusion in the QRH OEI Landing Descent checklist.

[@311gus]

Amazing work...with reference to RTO. ...can it be outbraked by manual inputs on the toe brakes? Or will RTO disengage if a pilot puts full braking force on a reject. Appreciate your time and the amazing effort on this content. Helps me alot in my personal learning and teaching. Gus

[@ChrisBrady737]

If you apply toe brakes the RTO will disengage. You can apply the same braking force with toe brakes as RTO but it is not the recommended technique. The FCTM states: "Operationally, the use of reverse thrust and autobrakes are recommended, however, maximum braking can be achieved either manually or with the autobrake set to RTO."

[@311gus]

@@ChrisBrady737 brilliant makes perfect sense and matches the manual at our airline. Thanks for your time to answer my question and thank for the time you take on these videos. They are a huge help in seeing the bigger picture for me and students who wish to learn more from the originals to the max! Invaluable this channel and content!

[@ChrisBrady737]

Glad you like it. Tell your colleagues and maybe get a copy of the book 👍

[@gliderman13]

Once again, Thank you very much for your very informative presentations. I have one question though, do you know by any chance the approximate cost of a single brake application (either steel and/or carbon)? Is it closer to 3€ per application, 15€ or maybe 40€? Or maybe you can provide any reference where I could find such data? Thank you.

[@ChrisBrady737]

I don’t have that data. It would be very difficult to be precise as there are so many variables such as landing weight, pressure altitude, temp, duration and strength of application etc etc

[@gliderman13]

@@ChrisBrady737 thank you very much for your quick response. That’s what I actually thought - too many variables to express it with a single value.

[@edgarmeloyan2399]

Hello ser thanks for great job. I have a one question. I work on NG and many times i see sings of hydraulic leak from brake hydraulic disconnect. I check on the ground, do a brake appliancations from A,B system set parking brake but not found any leak. Maybe pilots set autobrake max position?Maybe from EDP pressure is higher than EMPD?When I do a brake appliancations or set parking brake from EMDP how many psi go to the brake. What do you think about this?

[@ChrisBrady737]

I cant help troubleshoot your problem but Autobrake MAX is very rarely used because it is so severe. You can achieve maximum braking by application of the toe brakes.

[@edgarmeloyan2399]

@@ChrisBrady737 ok thanks

[@louisanderson6375]

Edgar: From the AMM Pt 1 (Training Man): B737NG Auto Brake Select Switch position vs Brake Pressure applied for each setting: Autobrake sel sw pos 1 = 1285 PSI/Autobrake sel sw pos 2 = 1500 PSI/Autobrake sel sw pos 3 = 2000 PSI/Autobrake sel sw pos "MAX" = 3000 PSI. Is this what you were seeking?

[@robsonbr1246]

Captain, what´s the reason that the speed for the landing gear retraction is lower than that one for the extension, thank you.

[@ChrisBrady737]

For retraction the nose gear has to operate against the airflow so the limiting speed must be lower.

[@robsonbr1246]

@@ChrisBrady737 Thank you!

[@aliamg4370]

Thank you for your amazing work , highly appreciated, i have a question please how could i decode this , 737-800SFP1 cfm56-7b26 C M KG FAA CATC/N fmc model 737-800w.1 ??

[@ChrisBrady737]

It is the aircraft model, engine, authority ruleset, brake category and winglet/SFP status.

[@aliamg4370]

Thank you so so much

[@kvuo]

shimmy damper

[@HammersnBlades]

Lol! So a 737-400 has a nose taxi weight of around 12,000 kg Whilst braking and landing this can almost double. So now you know that this stunt NEVER happened… 😂

[@ChrisBrady737]

Can you explain your comment, I don't understand it.