Questions tagged [landing-gear]

The wheels of an airplane. Sometimes replaced by floats or skis.

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16
votes
4answers
3k views

Why does the Harrier jet have four landing gears?

I was looking at pictures of Harrier jets and I noticed something. They have four landing gears. That seems pretty unusual for a fighter jet - most have only 3 in a triangle formation. What is the ...
13
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3answers
2k views

What is the cause of the noise heard when the landing gear is deployed?

Why is it that on most airliners, when the landing gear gets deployed, you always hear a loud noise like a bang. Is this due to the equipment locking in place or is there some other reason? As an ...
19
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1answer
8k views

How did the nose landing gear of JetBlue Flight 292 get stuck sideways?

The nose landing gear of the Airbus A320-200 was jammed, but the tires were perpendicular to the fuselage. How did that happen?
18
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3answers
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Why do certain aircraft's landing gear tilt up?

Why do the main landing gears of aircraft like the A330, 777, 787, etc tilt up? This does not happen with the 767. Interestingly, for the 747, the inner landing gear does not tilt up while the outer ...
22
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1answer
4k views

What airframe designer/manufacturer is credited with the first retractable landing gear system?

A quick follow-up to Why do planes always land on rear wheels instead of the nose wheels? What airframe designer/manufacturer is credited with the first retractable landing gear system? I ran past ...
48
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11answers
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Why do planes always land on rear wheels instead of the nose wheels?

Various times, I have seen and felt myself that the plane always lands on the rear wheels, but not the front wheels. Why do the pilots land it on the rear wheels instead of the front? Does it have ...
10
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2answers
325 views

Could landing gear weighing scales be used to detect lack of lift?

There have been several crashes due to ice on wings destroying lift. One of the issues with this is that you can't detect that you don't have sufficient lift until you're already in the air, way too ...
16
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4answers
5k views

How do landing gear retracting into the wing affect performance when deployed?

On many aircraft with low wing, landing gear (either wheel, leg, or both) retracts into the wing. Thus, when deployed, a significant part of the lower surface of the wing is not as clean as when the ...
17
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1answer
1k views

How do you perform a gear-up landing in a large airliner?

How do you perform a gear-up landing in a large airliner (say, a Boeing 747)? Would you fly it like a normal landing, or are there special considerations (angle of touchdown, use/non-use of thrust ...
18
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1answer
3k views

What's the technique for landing without one set of wheels?

A Boeing 747-400 recently made an emergency landing without the wheels under the right wing: News story Photo of the undercarriage Video of the landing from the end of the runway What's the standard ...
16
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2answers
3k views

How can the Pipistrel Apis land safely?

I just saw a photo of the Pipistrel Apis motor-glider, and it got me wondering: How can it safely land with only 2 wheels total? To me it seems that falling to the side would be inevitable, and with ...
15
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8answers
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What happens to the spinning wheels of the landing gear after takeoff, before retraction?

What happens to the spinning landing gear right after V2 on takeoff? Are they automatically or manually braked to a halt before gear retraction? Or are they allowed to spin to a halt in the wheel ...
17
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1answer
2k views

What is the purpose of aluminium foil on the wheels?

I saw this plane on a remote ramp at BKK today. What is the purpose of aluminium foil on the wheels? Does it mean the plane is in mothball? I don't see other planes, even in maintenance, with ...
8
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2answers
3k views

How many miles before the runway should an airliner put the gear down?

I was watching this video of a FedEx MD-10 landing and some questions came up, of course again the unprofessional YouTube comments didn't help. How many miles before the runway should an airliner put ...
9
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2answers
2k views

How does the nose wheel lock on the Robin DR400 work?

I recently learned that there is a locking mechanism on the nose wheel of a Robin DR-400. This mechanism locks the nose wheel in place when there is no weight on the wheel. In particular, the wheel ...
7
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1answer
15k views

How does the squat switch work?

This question came up after reading the following comments on the answer to this question: Raising the flaps right after touchdown. Good or bad? Philippe Leybaert Jan 20 at 23:00 The retractable ...
9
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2answers
2k views

Why did the backup landing gear deployment fail on LOT 16?

LOT 16 was a 767 which experienced a hydraulic leak, resulting in the failure of the landing gears and the proceeding belly landing shown below: Why did the backup ...
14
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3answers
9k views

What are the advantages and disadvantages of having landing gear doors?

To make comparison easy, let us take the example of B737 and A320, both similar aircrafts with retractable landing gear. As seen on the photo below, the B737 doesn't have gear doors for the wheels, ...
12
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3answers
3k views

Is there a best number of wheels per bogie?

I understand the need of having more wheels when the aircraft is designed to be heavier. The number of wheels per bogie and the number of bogies differ from an aircraft to another. For example, there ...
12
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4answers
3k views

How to execute a gear up landing on aircraft with low propeller?

On some GA aircraft such as the Piper Malibu, the propeller would touch the ground if the gear was up. How would you land the plane when gear actuators fail? I would pull out the mixture knob and ...
8
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4answers
1k views

Have landing gear collapsed at the gate?

Reading an answer to this question piqued my curiosity. Has there ever been an instance of an airliner's landing gear collapsing while loading/unloading passengers? I do not include after emergency ...
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2answers
2k views

What are the states that the landing gear can be in?

What are the valid set of enumerated states for landing gear? My current working set is: DOWN DOWN & LOCKED STOWED STOWED & LOCKED INOPERATIVE CYCLING_UP CYCLING_DOWN Also, are there any ...
6
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7answers
5k views

Do some aircraft lower the landing gear mid-flight?

Are there situations in which a pilot could/has to lower the landing gear during flight for reasons not directly connected to landing? (i.e., not part of the landing checklist) Originally I thought I ...
18
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4answers
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Why do most aerobatic aircraft have conventional landing gear?

I was browsing images of aerobatic aircraft on Google and noticed that the vast majority of them have conventional "tail-dragger" landing gear. Is there any practical reason why this is the case, or ...
8
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3answers
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Will landing gear with wheel fairings keep spinning due to airflow?

I asked this in a side note to a previous question, but I figured it warranted its own question. If a fixed gear aircraft is fitted with wheel fairings, even if you tapped the brakes after lift-off, ...
28
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7answers
8k views

Why tap the brakes on take-off in fixed gear aircraft?

The Socata TB10 checklist indicates that you should touch the brakes after lift-off. I assume this is to stop the wheels from turning, but why? In a retractable gear aircraft this would make sense to ...
68
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2answers
29k views

Why are aircraft tires not pre-spun prior to landing to preserve them?

Why has someone not designed a landing wheel with a fin or fins on it so that the air will start the wheels turning before the wheels touch the ground? Wouldn't that preserve the tires longer from ...
22
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3answers
8k views

When do pilots deploy landing gear?

The landing gear should be down in order to qualify as a stabilized approach. Other than that, what are the guidelines on when to deploy landing gear on approach?
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2answers
897 views

What are the pros & cons of Autobrake?

What are the advantages/disadvantages of an autobrake system? In particular I am interested in the Fokker 100 system. Have any studies been done for the F100 autobrakes and the affects that this ...
15
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1answer
2k views

Do landing strips suffer from potholes or rutting?

In companion to the other question asking about wheel tire tracks. Planes come down and stop with a significant amount of force which I would expect to cause either rutting or potholes. Are runways ...
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3answers
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Do landing strips suffer from landing wheel tire tracks?

I've now seen several landing strips up close and there are lots of tire tracks from planes' landing wheels. I wonder if it somehow modifies the properties of landing strips to make for poorer landing ...
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7answers
6k views

Will the landing gear work mechanically in case of total power loss?

In case of a total power failure in all the aircraft systems like engine failure and APU failure, would it be possible to use mechanical means (manually) to open the landing gear bay door and deploy ...
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5answers
5k views

Why are military and civil aircraft landing gear generally so different?

Why do military aircraft have a lower landing gear than civilian? I have in mind the difference between a Lockheed C-130 Hercules and a Boeing or Airbus. The first possibility that jumps to mind is ...
25
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2answers
7k views

Are large passenger aircraft steered during taxi by changing the angle of the front landing gear?

When moving to and from the runway, does a large passenger aircraft turn by changing the thrust difference on its side engines, or by turning the front landing gear to a different angle? If it is by ...
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4answers
7k views

Why were flying boats phased out?

Before WWII, flying boats were a popular form of transport, and the advantages are many: No need to build runways, capability of emergency landing on water, availability of large landing sites and no ...
8
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2answers
701 views

How much drag do the gear doors create during retraction?

It's been said that if you retract the gear at a critical moment that performance will actually be worse than if you left the gear down. However, is this really true, and just how long is the ...
17
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1answer
3k views

Why is there a difference between nosegear retraction directions?

I've noticed that on almost all aircraft (Boeing, Airbus etc.) the nose gear rotates forwards for retraction. However, on a some aircraft, in particular a few Russian models, the opposite is used: ...
18
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3answers
20k views

How long do airliner tires last? Can this be improved?

I imagine that the tires on commercial jets wear out pretty fast with all those squealing landings as the tire suddenly has to spin up from zero to the speed of landing. 2 questions: How many ...
19
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1answer
4k views

Is the main landing gear of a large airplane designed for sideways (crabbed) touchdowns?

Is it just my imagination, or is it a fact that many large airliners actually touch down "crabbed" on difficult crosswind landings? Here's what I mean in this video, or as shown in this picture: Is ...

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