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Is it better to shut down the engine(s) or leave it (them) running when a gear up landing is imminent?

I noticed that the pilot in this video chose to shut down his engine before touching down during a gear up emergency landing. However, in Pilot Operating Handbooks, the recommendations seem to be mixed. For example, the Cessna 210 POH, Page 3-11 says:

  1. Touchdown -- SLIGHTLY TAIL LOW.
  2. Mixture - - IDLE CUT-OFF.
  3. Ignition Switch -- OFF.
  4. Fuel On-Off Valve -- OFF (pull out).

On the other hand, the POH for the Piper Arrow III PA28R-201, Page 3-14 recommends shutting down the engine before touching down:

3.lSb Gear Up Emergency Landing (3.Sd) When committed to a gear up landing, CLOSE the throttle, move the mixture to idle cut-off, and shut OFF the ignition, battery master (BATT MASTR), and alternator(ALTR) switches.Turn OFF the fuel selector valve. Seat belts and shoulder harness should be tightened. Touchdown should normally be made at the lowest possible airspeed with full flaps.

What is the reason for this variation? Is there some advantage to touching down one way vs. the other?

I've have noticed this question:

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

However, I do not believe this question duplicates that one. While consideration of the propeller would be one factor in deciding whether or not to shut down the engine, it certainly would NOT be the only one.

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    $\begingroup$ I would leave them on, what if you need to go around at 20 feet? $\endgroup$ – Ron Beyer Jul 10 '17 at 20:41
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    $\begingroup$ While I would follow the POH/AFM, what I was told is that shutting the engine down prevents internal engine damage due to the propeller contacting the ground under power and could save an expensive engine overhaul (in addition to the fuselage damage which will occur). $\endgroup$ – Lnafziger Jul 10 '17 at 21:22
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    $\begingroup$ Isn't the only correct answer to follow the POH? $\endgroup$ – CGCampbell Jul 11 '17 at 18:03
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    $\begingroup$ I just happened across This AVweb video about the subject. He makes some very good points as to why you are best leaving the engines running. The advantages to cutting them are actually pretty pointless. You're most likely not going to save your props. Fires on belly landings in ga aircraft are rare. The engines will need to be inspected anyway. $\endgroup$ – TomMcW Jul 15 '17 at 0:00
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    $\begingroup$ Could point #8 refer to making a PLAN for touchdown, rather than an instruction to WAIT for touchdown before proceding with later steps? If so, that would be sloppy writing, but... ? $\endgroup$ – quiet flyer Oct 25 at 20:03
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There's two schools of thought. First is the keep the engine on school because keeping the engine on:

  • Gives you more control of the airplane
  • Gives you the option to go around
  • Keeps the procedure simple and allows the pilot to concentrate on a good touchdown
  • Keeps the dynamics of the airplane predictable and familiar to the pilot

The shutdown the engine school's view is that shutting the engine down lowers the fire risk by cutting off the fuel and engine ignition spark.

Personally I'm with the keep the engine on school of thought. The last thing I want to be doing when I'm trying to make a smooth landing is reaching for all sorts of knobs and levers, and having to reach the fuel cutoff valve in the inconvenient places that piper likes to put them, and then learning how the airplane behaves without engine power for the first time. As soon as I touch down I am pulling the mixture, cutting off the fuel and killing the mags and the master switch, but until then I'm going to concentrate on making it the smoothest landing in the history of manned flight.

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    $\begingroup$ I've heard some say they shut down in an attempt to save the props... but from the plethora of youtube videos... that doesn't seem to go right most of the time. $\endgroup$ – SnakeDoc Jul 10 '17 at 22:01
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    $\begingroup$ It doesn't @SnakeDoc, it's a spectacularly bad idea. You are intentionally creating an emergency you wouldn't ordinarily dream of doing which is far more serious than the one you have. $\endgroup$ – GdD Jul 10 '17 at 22:11
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    $\begingroup$ You're going to have an insurance claim anyway, since there's no escaping damages with a belly landing. Saving the props is likely the least of your worries. $\endgroup$ – SnakeDoc Jul 13 '17 at 14:50
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    $\begingroup$ Yes there's going to be sparks either way @Sean, it'll be from the skin of the airplane, not electrical wiring. The voltages on GA airplane electrical wiring generally isn't enough to cause any sort of sparks. The wheels up landing procedure for an airplane should call for master off, fuel valve cutoff to limit the danger from the electrical system and fuel system. $\endgroup$ – GdD Apr 27 '18 at 8:18
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    $\begingroup$ Oh, I see @Sean, you're right that there's going to be plenty of sparks. In this case I was referring to engine spark, the amateur auto mechanic came through I guess. The thinking is that in a forced landing turning off the magnetos and cutting off the fuel supply to the engine reduces the chance of a post crash fire, which is true. However, a gear up landing is not the same thing, the instances of fire is much less, and usually fire crews are in attendance anyway. $\endgroup$ – GdD Apr 27 '18 at 17:57
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Prior military Flight Engineer, current aeronautic contractor employee here. In the KC-10, engine shutdown on contact with ground is dictated in order to minimize potential fuel spill and fire hazard. I would imagine that many aircraft have different procedures dictated by their design and engineering features such as landing gear and engine configuration.

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    $\begingroup$ The question seems to be focusing on small propeller planes, which will be a little different from the KC-10. $\endgroup$ – fooot Jul 10 '17 at 21:25
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    $\begingroup$ Actually, I had not intended to limit this to small propeller airplanes, though that is certainly where my own experience lies. $\endgroup$ – bclarkreston Jul 10 '17 at 22:23
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    $\begingroup$ Fantastic real-world answer! $\endgroup$ – Fattie Aug 28 '18 at 11:10
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Both actions quoted result in engine off landings. Repairing a prop strike on just the motor can easily cost 1/3 the price of a motor plus a propeller. Saw a video of a guy landing gear up in a twin, he shut it down after he knew he had the runway and bumped the starters to put the props horizontal. Saved at least 40 thousand dollars doing it.

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    $\begingroup$ As soon as you have an emergency, the insurance company owns the plane and your only concern should be survival, not saving their plane. $\endgroup$ – StephenS Oct 26 at 17:00
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I fly a low-wing, 4 engine turboprop. We would shut down the engines by cutting off fuel, but not feather the props prior to hitting the ground. There are several reasons for this.

1) The fire will go out in the engine, reducing the potential for fire.

2) The RPM of the prop and engine will be drastically reduced, for us it will probably drop to about 35% of normal operating RPM. This reduces the rotational energy, and how badly the prop blades throw fragments when they hit. On our plane the inboard props will hit before the outboards. We also would clear personnel from any seats near the prop plane of rotation or else they're probably going to get hit.

3) We don't feather the props because they are more likely to just bend or break off the tips if the blade angle is flat. If they are feathered, they might tear the gearbox and engine off the plane entirely. This is a measure to limit damage to the airframe, not really a concern about cost savings. There is an awesome video on YouTube from the show Ice Pilots of a Lockheed Electra (very similar to my plane) landing with one of the mains up. They followed basically the same procedure I mentioned and walked away with a lot less damage than I would have expected.

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You mostly don't need to shut down fuel with aircraft with fuel tanks on the top but lets be on the safe side. This is what I would do (I Am not that great in landings):

  • Aircraft Cessna 172SP
  • Near landing means 250Meters behind the aiming point
  • Full flaps on near the landing
  • VSI is lower than HSI
  • Nose little bit up
  • Near stall speed

I Would shut down the engines and cut the mixture in order to minimize odds of getting fuel burned. Then I would try to stop on the field as fast as possible. You will not need to shut down the engine withing 250Meters of the aiming point on aircraft with fuel tanks on the top but do that procedure as n habit. Also you wont need engines on a properly planned landing unless you are an aircraft carrier pilot that is afraid of your tail hook not catching the arresting gear.

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