Pre-flight check gone bad. (PIREP)

[alex]

A few days ago while doing the pre-flight, just before taking the active runway, I was making sure the controls were "free" and "correct". Ailerons checked out ok, rudder was fine, when I did the elevator check to the full up position something clicked and elevator was completely stuck. I tried to bring it down but it would not budge at all, nothing I tried brought it down. I went back to the hangar and started taking off inspection panels, including belly, to make sure nothing was bent and found everything to be in good shape. It turns out one of the bungee assy-trim assy (what looks like an actuator with a nut in the back of it) malfunctioned and got jammed. The elevator came down when that nut that sticks out of the back of the assy was turned back and forth. I ended up purchasing two from Mooney (no point in just replacing one). They are not cheap and  they only have 4 more in stock at $956.45 each. I am posting this now because I was thinking about all the previous times where I may have not done the check to its full travel and I wonder if for some reason I may have needed to avoid something, would that elevator have gotten stuck in midflight? Who knows, either way you guys should check that on your next flight....

[David Mazer]

Thanks for the information.  I certainly will.

[Parker_Woodruff]

Good catch.  Did you have any ability to move the trim prior to finding the cause?

[Parker_Woodruff]

I need to read NTSB 830 in a bit more detail - but you might be required to report this as an incident.  "Flight control system malfunction or failure"

[Hank]

Is a failure of anything on the ground prior to departure reportable? In-flight failure of flight control systems would be, but on the ground while taxiing before departure?? I'll have to read the FARs for this one.

[alex]

I was able to use the trim but it would not have made a difference in flight. I explained what happened when I called Mooney and they didn't mention anything about reporting the issue...

 

Parker, everything was normal. It was just one of those days when I decided to go full deflexion for the control check, had I done the normal, i'm not going to say "lazy" but not full up/ down I probably wouldn't have found the problem.

[Parker_Woodruff]

Quote: Hank

Is a failure of anything on the ground prior to departure reportable? In-flight failure of flight control systems would be, but on the ground while taxiing before departure?? I'll have to read the FARs for this one.

[N9937c]

The elevator bungee assembly rarely gets jam. But when it binds or get jam is due to lack of lubrication or rust. I should be lubricated at every annual specially if the plane is not hangared. Typical initial symptom is occassional binding. This looks to me more of lack of proper maintenance than a part defect. There is no need to report it.

José    

[alex]

Quote: N9937c

The elevator bungee assembly rarely gets jam. But when it binds or get jam is due to lack of lubrication or rust. I should be lubricated at every annual specially if the plane is not hangared. Typical initial symptom is occassional binding. This looks to me more of lack of proper maintenance than a part defect. There is no need to report it.

José    

[jlunseth]

Looks reportable to me.

830.2       Incident means an occurrence other than an accident, associated with  the operation of an aircraft, which affects or could affect the safety of operations.

830.5        Immediate Notification.  The operator of any civil aircraft  ...  shall immediately, and by the most expeditious means available, notify the nearest [NTSB office] when:

     (a) An aircraft accident or any of the following listed serious incidents occur:

          (1)   Flight control system malfunction or failure... .

So if it could affect the saftey of ops it is an "incident."  Whether it is a "serious incident" is answered by the list in (a) which includes a flight control system malfunction or failure.   The "inflight" issues in the 830.5 (a) list are crewmember unable to perform duties, inflight fire (but not ground fire), inflight aircraft collision, plus some other things relating to larger aircraft and EFIS's. 

 

 

[David Mazer]

Without sounding too naive, isn't it easiest to report it even if it doesn't need to be vs not reporting it if it does?

[Piloto]

Quote: alex

 When opened, there was no rust it had what appeared to be grease.

[DaV8or]

Wow! I'm so glad you caught that! That could have killed you! I'm in the middle of an owner assited annual at LASAR right now and I will ask about this tomorrow.

Thanks for sharing.

[flyboy0681]

Scary as all hell if you ask me. The unthinkable may have happened had this occurred in flight.

[Guest]

When you take the bungees apart I feel they should be totally cleaned and de greased then apply new. Old grease does go bad. I bet most bungees in the fleet rarely get properly inspected and serviced.

 

 

[Piloto]

Quote: flyboy0681

Scary as all hell if you ask me. The unthinkable may have happened had this occurred in flight.

[flyboy0681]

Quote: Piloto

You still have pitch control with the stabilator trim. Unlike other planes that employs elevator trim the one on the Mooneys is totally independent of the elevator. Due to the use of actuating push and torque tubes the flight controls in a Mooney are highly reliable and less prone to failures than those that use cables. In a Mooney broken aileron rod end will not impair functioning of the other aileron. While in a Cessna a broken aileron cable will impair both ailerons leaving you with rudder only for roll control.

José   

[alex]

Quote: BluSky

When you take the bungees apart I feel they should be totally cleaned and de greased then apply new. Old grease does go bad. I bet most bungees in the fleet rarely get properly inspected and serviced.

 

 

[M016576]

Quote: flyboy0681

You still have pitch control with the stabilator trim. Unlike other planes that employs elevator trim the one on the Mooneys is totally independent of the elevator. Due to the use of actuating push and torque tubes the flight controls in a Mooney are highly reliable and less prone to failures than those that use cables. In a Mooney broken aileron rod end will not impair functioning of the other aileron. While in a Cessna a broken aileron cable will impair both ailerons leaving you with rudder only for roll control.

José   

[jetdriven]

Quote: Piloto

You still have pitch control with the stabilator trim. Unlike other planes that employs elevator trim the one on the Mooneys is totally independent of the elevator. Due to the use of actuating push and torque tubes the flight controls in a Mooney are highly reliable and less prone to failures than those that use cables. In a Mooney broken aileron rod end will not impair functioning of the other aileron. While in a Cessna a broken aileron cable will impair both ailerons leaving you with rudder only for roll control.

José   

[Piloto]

Quote: jetdrive

Not with full up elevator......

I would report it to the NTSB.  "Flight time" occurs when the aircraft moves under its own power for the purpose of flight.

[alex]

Quote: Piloto

José

 

[jetdriven]

This could also develop into a recurring problem that could kill someone else.   This is how AD's are created.    It is not the time for CYA, and besides it is a federal reporting requirement.  

[WardHolbrook]

Just a question...

Are you guys checking for full flight control (elevator and aileron) travel as you taxi out as part of your before takeoff checklist, everytime, every flight? It's normally not possible to check the rudder, since it's connected to the nose wheel, but at least you can check that for freedom and ease of movement. If not, you really should.

[Immelman]

Yikes. Yikes..

I would not count on the ability to fix this with trim once airborne. Unless a pilot detects this at about rotation at the latest, I think the outcome would be very bad. As much as I do not want to have an AD on my hands I think this ought to be reported.

Regarding checking the controls: I absolutely do this before each takeoff. Further, I suggest (and teach to students) 'boxing' the controls as follows: Full aft elevator, hold it --> full right aileron & hold it --> full forward elevator and hold that --> full left aileron, and so on, as if you're tracing the corner of a box. My thinking on this is that you're then exercising the moving parts behind the panel to their extremes in both axes.