Runaway Trim?

[328dude]

Had it happen in a Merlin once. Not fun. Servo went nuts and the breaker was behind me. Banking the plane to kill the Lift Coefficient (sp) helps till you figure it out. Not fun for the PAX but hey.

Anywho, great job by the crew.

 

[lazy8s]

I was wondering if anyone had heard about a CHQ ERJ that had to declare an emergency Thursday night coming out of BOS heading for ROC due to a possible runaway trim problem?

TO ANSWER YOUR QUESTION, IT DID HAPPEN,
THIS IS A QUOTE FROM THE CAPTAIN ON THE FLIGHT:

Although it hasn't been determined the cause for the pitch up attitude, I do know that I had the controls in the FULL forward position and we were still entering into the stall area. Although we never recieved a stick shaker, it was seconds away and by 6000' we were able to somewhat control the airplane with the control FULL forward.


I had a friend that was on the flight. He is a private/inst pilot (but not a professional pilot). He said that the takeoff and first few minutes were normal. Then about 5 to 7 minutes in to the climb the nose started to pitch up beyond what he felt was a normal climb attitude. Soon he heard numerous bell's and whistles coming from the flight deck. He then started to feel the plane buffeting from the imminent stall.

-It's amazing what Private pilots know about flying high performance Jets...
-As stated above, the plane NEVER got the shaker, which by the way comes BEFORE a buffet.

Does anyone know what actually happened with this plane?
I have heard that this kind of thing has happened before on the ERJ, true? If this is true, are ERJ crews trained on how to handle this situation in the sim? What do ya think? -Beantown

To answer your other questions, we DO train for runaways in the sim as well as windshear and any other unusual flight condition for the type of Aircraft. That and a skilled and experienced flight crew has a lot to do with why the flight ended safely and not as a smoking crater.

 

[Mr Freeze]

The important thing is that everybody walked. The Crew did one hell of a job bringing it around and landing safely. I still dont understand why your friend had to rent a car. I wonder what he would do if the engine quit in his airplane with him at the controls.

 

[Beantown]

Freeze boy, If the engine failed in his plane, I am sure that he would land it, get it fixed and fly another day. It is totally different when you are not in control of your own life. Of course you would not have been effected because you are MR FREEZE!!! Get a life! -Beantown

p.s Mr Lazy8's, My friend had no inside knowledge of what happened in the flight deck that night. The fact that he thought it might be runaway trim and that he thought he felt the plane shutter just goes to show what a knowledgeable pilot he is. You don't have to be a "cool" jet pilot like you to understand when a plane is in trouble. -Beantown

 

[BigFlyr]

I've heard of a similar situation happen to a CRJ Captain friend of mine, where the controlls had to be held full forward for the remainder of the flight. Of course, when I when through the training program for the CRJ 200 myself, the Canadair ground instructor said that it was not possible due to system override design of the elevator servos. Yeah right... Well he's just selling airplanes. Also, in the CRJ the runaway trim situation can sneak up on you rather quickly since there is no trim wheel... just a small electronic representaton of trim setting then a warning bell... I imagine the ERJ is similar. Glad not to be flying that squirelly thing anymore! Hats off to you guys that still do!

 

[328dude]

I'm just curious, but dosen't the "jungle weed" have some sort of elevator disconnect unit?. I can only speak for what I fly, but was wondering if your able to split the elevator by pushing or pulling in oppsite directions. I know you can on the dorkjet as well as the aileron's.

Is this also an option on the CRJ,ERJ,Avro,717, etc etc etc.....

 

[sabreliner]

I don't know about the Brasilia Jet, but on the Brasilia prop, we can mash the autopilot/trim disconnect switch. The 6 autopilot/trim servo breakers are also collared on the overhead for easy pulling. Don't know if this would have helped in the above mentioned situation, but figured I'd throw it out there.

 

[EagleRJ]

The ERJ has an elevator disconnect, like every other transport-category aircraft, that can be activated either by pulling a handle or breaking the "clutch" between the two sides. That is only useful in case of a jam somewhere in the system, when the other side is unaffected. A stalled or runaway trim motor affects both sides, since the stabilator is moved too far up or down.