Runaway Trim?

[Beantown]

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?

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. This lasted for a few seconds and he then saw the flaps go down a notch and it seemed that the crew was starting to get control (at least a little bit) of the plane. Soon after the flight attendant told the pax that they were returning to Boston and starting going over how to survive a crash landing. At this point the pax were in full panic and calling there love ones and saying there goodbyes. He said that it felt like the pilots were struggling to keep the plane in the air and that they were not at normal flying speed. The crew was able to get the plane on the ground and to my knowledge no one was hurt. (Kudos to the crew and the flight attendant). My friend was so shook up by the experience that he rented a car and drove back to Rochester. (He is an experienced pilot that owns his own small plane, so that shows you how rattled he was).

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

 

[chperplt]

Don't know about the flight, but you write a good story... ever think about writing books???

 

[skydiverdriver]

So, the pilots let it get close to a stall, without simply pushing that little button that turns off the autopilot? This doesn't sound plausable to me, but I have been wrong before.

 

[InHot]

Autopilot/Stab Trim

Bubba,

You know better. Runaway stab trim isn't necessarily associated with the autopilot. Don't know about the ERJ, but every jet I've flown had a stab trim switch you can use to disconnect the trim.

Maybe, it didn't work, who knows.

In any event I've learned never to armchair QB.

 

[atk]

On this particular flight the pitch trim from what I understand went to the full up position. This has been a problem with the EMB, the NTSB and FAA are investigating. The crew did a great job maintaining control of the A/C!! From what I understand "pushing the little red button" didn't help!!!!!!

 

[DorkProp]

Okay, this isn't really related to this thread, but not worthy of starting a new one.

In line for takeoff at CVG yesterday with 30-40 knot gusts, we were number 274 for takeoff (only slightly exaggerated). In front of us were boeings, douglases, a BAC jet, several CRJs, ERJs, and a DorkJet. The wind was directly from behind. All the aircraft's elevators were rigid and deflected down and seemed to not be affected by the strong wind. However, all of the ERJ's elevators were literally "flopping" nearly full-scale up and down at a rapid pace. Is there a flaw in the design of their gust lock? That just looked really bad for the elevators and control mechanisms.

Just wondering, not that this has anything at all to do with runaway trim.

 

[EagleRJ]

The gust lock is a problem on the ERJ, however it is not related to the pitch trim problems. The gust lock is a mechanical lock in the cockpit, and when you figure in over 100' of control cable, the elevator really takes a beating when the wind is blowing. Embraer and the companies that fly the plane have been aware of the issue and are working on a solution.

The pitch trim problem stems from the fact that there are two pitch trim servos- a primary and a standby. They operate independantly, and when the tail is highly loaded, it's possible for the servo to become stalled and unable to move the tail. This happened for the first time to an Eagle crew in Chicago, and they did a heck of a job getting the plane back on the ground. As far as I know, Embraer is working on that problem too, maybe by reworking the trim system so that both servos work together.

 

[Beantown]

<<<As far as I know, Embraer is working on that problem too, maybe by reworking the trim system so that both servos work together.>>>

They may want to hurry up and rework the problem before many get killed!!! -Beantown

 

[stingray]

"Know where your breakers are", if you can't disconnect the trim pop the breaker

 

[EagleRJ]

"Know where your breakers are", if you can't disconnect the trim pop the breaker

That wouldn't help. This isn't a runaway trim issue- the trim servo is stalling and is unable to turn the jackscrew. Running the procedure for a runaway trim just gets you into more trouble, because the checklist tells you to disable the primary trim servo and use the standby, which will reduce your chances of retrimming the aircraft.

 

[xrjpilot]

My former employer has a procedure to avoid the stab overload condition. start retrimming the stab before 160 kts.

What happened in BOS was a run-away trim condition. What bothers me about it was the pitch trim disconnect button didn't stop the trim actuator.

I wasn't there...So I don't really know. Hats off to the professionals that did a great job.

 

[ultrarunner]

My former employer has a procedure to avoid the stab overload condition. start retrimming the stab before 160 kts.

I've seen a placard that says just that in the ERJ

AND another thing....I can't think of a good reason, other than economics, not to ground the fleet if the crew has no way to stop this problem.

 

[chperplt]

The aircraft in question was released back into service today from Boston. The mechanic could not find any problems with it.

 

[ultrarunner]

The aircraft in question was released back into service today from Boston. The mechanic could not find any problems with it.

Ahhh, the good 'ole "Could Not Duplicate". Yeah, take 'er back up, it'll be OK.

geez

 

[xrjpilot]

It was flown to LGA on a ferry permit. CHQ doesn't have MX in BOS.

 

[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!