Stabilator question...

[rgmwa]

The recent accident threads, Bowden cable notification and lack of redundancy discussions had me wondering whether it was possible to control an aircraft fitted with a cable-actuated stabilator following a cable failure. I know you may be lucky and get away with it in a normal stabiliser/elevator equipped aircraft, but had assumed that a stabilator would be would be virtually uncontrollable. However, I found this snippet that suggests it may be survivable...

 

An incident that occurred on December 8, 2008, regarding the loss of horizontal stabilator control on a Piper Model PA-28-151 airplane (Total Hours: 2650, Manufacturing Date: Unknown). The pilot landed safely using elevator trim and engine power.

 

I have a vested interest in this as my aircraft has a stabilator, so I'd be interested to hear what the experts say or whether anyone has had a stabilator cable break and got down safely.

 

rgmwa

 

 

[facthunter]

If you have a trim tab and the stab has become disconnected so it is free to move, you should be able to control the plane in pitch( IF there is no flutter) on the trimtab. You might also balloon the thing badly on the landing so there would be an appropriate technique to use to minimise that possibility. IF the control jambs the trim tab may work but in the opposite sense and you won't have a big range of control on the trimtab alone.

 

A comment generally on a full flying tail. They are extremely hard to get right as to their aerodynamic balance and structural rigidity. Bill Whitney doesn't like them, not do I..( I'd take more notice of Bill than Me.) Nev

 

 

[rgmwa]

Nev, I assume you mean the anti-servo tab? In my case the anti-servo tab trim adjustment is electrically controlled, so I'm wondering how quickly it could respond in controlling the plane. I guess the obvious answer is to do a bit of experimenting at a safe altitude one day to see how effective it is.

 

rgmwa

 

 

[facthunter]

Controlling it won't be easy during the flare as it's too slow generally in it's response. Play with it at height. I would use power on the approach in a real situation and cut it to ensure it doesn't skip.. I have had an actual elevator failure in a larger aircraft but with spoilers to pin it on it's a non-event I would NOT OWN a plane that doesn't have a secondary way of controlling pitch. Nev

 

 

[dazza 38]

theith the righ weather condityio

 

The recent accident threads, Bowden cable notification and lack of redundancy discussions had me wondering whether it was possible to control an aircraft fitted with a cable-actuated stabilator following a cable failure. I know you may be lucky and get away with it in a normal stabiliser/elevator equipped aircraft, but had assumed that a stabilator would be would be virtually uncontrollable. However, I found this snippet that suggests it may be survivable...An incident that occurred on December 8, 2008, regarding the loss of horizontal stabilator control on a Piper Model PA-28-151 airplane (Total Hours: 2650, Manufacturing Date: Unknown). The pilot landed safely using elevator trim and engine power.

 

I have a vested interest in this as my aircraft has a stabilator, so I'd be interested to hear what the experts say or whether anyone has had a stabilator cable break and got down safely.

 

rgmwa

Yup, the Piper Archer is the same, even with a full flying elevator/stabilator, a landing can be done with trim only . It may be messy though (but doable) with the right weather conditions and things going your way.

 

 

[Marty_d]

Talk of control loss, especially in pitch, makes me think that perhaps that $7,000 / 14kg BRS insurance policy is not a bad idea. I've read the arguments for and against on another thread, including the one that it may lead to complacency and be deployed unnecessarily, but if it came to the choice of trying to land the plane with the electric trim tab or popping the chute over a safe area, I'd pop the chute every time.

 

 

[Bob Llewellyn]

theith the righ weather condityioYup, the Piper Archer is the same, even with a full flying elevator/stabilator, a landing can be done with trim only . It may be messy though (but doable) with the right weather conditions and things going your way.

The ASTM doesn't require it, but CAR 3 / FAR 23 require an aeroplane be landable with - from memory - any primary control system failed. The Thruster is not a good look with control failure...

 

 

[nong]

When I owned a Thruster it got a fixed (bendable) tab on the elevator as soon as I could find the rivet gun. I set it to a trim speed of 45 knots. No way did I trust that UP elevator cable to stay connected to the horn. The horn had a sharp edge that wore the cable attach bolt.

 

 

[facthunter]

You could probably fly the thruster on power set up like that. You can also move forward and back a bit. Adjustable trimtabs are not without their problems, too. If the actuator becomes disconnected they usually flutter Nev

 

 

[Old Koreelah]

Talk of control loss, especially in pitch, makes me think that perhaps that $7,000 / 14kg BRS insurance policy is not a bad idea. I've read the arguments for and against on another thread, including the one that it may lead to complacency and be deployed unnecessarily, but if it came to the choice of trying to land the plane with the electric trim tab or popping the chute over a safe area, I'd pop the chute every time.

I had the same attitude, Marty, but the more I learn about BRS landings the more I want to avoid using it.

Mine is soon due for a re-pack, an opportunity to improve the installation.