Emergency Landing Gear Extension - Keep It Simple
Pilots flying aircrafts with retractable landing gear must know three things: how to extend and retract it, the speed restriction for its operation… and the emergency extension procedure. As any equipment on board, the landing gear extension system can fail, and manufacturers have to plan an emergency system.
On the PA-32 Saratoga, the gear is operated with a dedicated hydraulic system, which is rather simple. When the gear must be retracted, the pump creates pressure on the appropriate side of a cylinder, which raises the gear. To extend the landing gear, the pump removes pressure, by moving liquid back in a tank.
One of the drawbacks in this system is that if pressure diminishes in flight, the gear can move, and the pilot gets a warning. This also re-activates the pump, which brings the gear in the “fully up” position. The first time it happens is always a surprise to new pilots !
The Bonanza uses a full electrical system. Gears are mechanically linked to a “master wheel”. When the wheel rotates in one direction, the links bring the gear up. When the wheel motor drives it in the other direction, the links bring the gear down. No pump, no liquid, no hydraulic circuit. The gear won’t move by itself, as nothing will move the master wheel.
So is one of these systems better than the other one ? In normal operations, the answer seems obvious. But emergency operations is another world…
The emergency system to extend the Bonanza’s landing gear is a crank coupled to the master wheel. It’s normally folded betweent he pilot’s and co-pilot’s seats, in a relatively aft location. If the gear engine fails, the pilot must unfold the crank, and turn it… 50 times ! The first turns are easy, but then the air resistance to the unfolding gear comes in the game, and more force is required to turn the crank.
I practiced that a couple of times, and I it took something like two and a half minutes. If this happens in VMC condition, or IMC with autopilot working, this can be done. But if the reason of the failure is a total loss of electrical power, the whole procedure must be done without auto-pilot. Good luck.
The Saratoga’s hydraulic system includes a by-pass valve. If the gear can’t be extended normally, pull the lever to open the valve. The fluid in the cylinder will go back to the tank, and after 9 seconds, the gear will be extended. That’s it. Ok, one must first reduce speed to 90 kts, instead of the usual 132, but that’s no big deal.
So, which system do you prefer now ? If you know other systems, let me know which is your favorite.
2 Comments, Comment or Ping
Jess Sightler
I like the old Mooney system. It was a johnson bar, similar to the flap handle on the Piper’s and was pure mechanical. From what I hear it did take a bit of getting used to, but they almost never break (low maintenance costs) and you never have to worry about a failure causing trouble in the air.
The worst is on the Cessna high wing retractables (172RG, 182RG, etc). They are hydraulic, but they will not fall into place on their own due to the nature of retracts on a high-wing aircraft. The backup hydraulic system is close to useless as well from what I understand. In most cases manual extension just doesn’t work at all (thus all the videos of Cessna’s landing with the rear gear flopping), though I have heard of some creative souls getting them to extend by hanging out of the aircraft with a golf club.
Of course, the most interesting thing to me is still the misconception among non-pilots that a gear up landing is a major near death experience. Most of the time all that gets hurt is an airplane belly and a wallet.
May 4th, 2008
PlasticPilot
Thank you Jess for this complement. I never liked the look of the Cessna system either. On the plus side however, the visual check is much easier, thanks to high-wing.
There is a third thing that gets hurt in a belly landing: pilot’s ego. I’m still part of the club of pilots who never landed gear up, waiting for my admission in the other club…
May 5th, 2008
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