trim check

[poteroo]

Many decades back, a type endorsement required that a full load check be done at the end. Recall several surprised endorsees who'd left the trim with nose up after the last 2 people only landing. The extra load in the rear 2 or 4 seats did cause the ship to really pitch up immediately at near liftoff !! Bet they never forgot to retrim again !

 

 

[Guest RogerRammedJet]

Many decades back, a type endorsement required that a full load check be done at the end.

 

Surely that should still be a requirement - especially in any aircraft with a large CofG range.

 

Rog

 

 

[Yenn]

The way I see it there are 2 places where incorrect trim should be spotted before flying.

 

Firstly during the walk around, the tab would be off centre, but this would depend upon the pilot being familiar with it's usual location.

 

Second it should be part of the pre take off checks. My checks start off with "Trim, Throttle, Mixture etc".

 

 

[Methusala]

I use " controls rise to meet the stick ", when checking for correct sense. Easy to remember and simple to visualise. Regards, Don.

 

 

[Flyer]

Fantastic method Methusala. Never thought of that but I'm using it now. Stops the mental gymnastics.

 

regards

 

Phil

 

 

[hihosland]

Ian Borg did say """

 

The way I see it there are 2 places where incorrect trim should be spotted before flying.

 

Firstly during the walk around, the tab would be off centre, but this would depend upon the pilot being familiar with it's usual location.

 

Second it should be part of the pre take off checks. My checks start off with "Trim, Throttle, Mixture etc". ""

 

So last week I did both of those checks and still had confusion if not trouble.

 

Trim tab looks OK on walk around, trim lever set to desired take off position before rolling.

 

In the air the aircraft needed significant nose down trim where I expected it to be neutral. Much puzzlement and some concern.

 

On the ground a thorough examination revealed that the outer sheath of the trim Bowden cable had come out of its socket thus changing the position of the trim indicator relative to the actual trim tab.

 

Easily fixed.

 

Easily missed.

 

Davidh

 

__________________

 

 

[motzartmerv]

Well you blokes have certainly opened my eyes to the problem..im stepping up from the jab into a cherokee soon.. ill deffinatly be keeping this problem in mind..

 

Thanks;);)

 

 

[poteroo]

A useful check of the elevator trim is to have a 2nd person wind the trim through its' complete range. The outside person can then mark both limits of movement, then the mid point of the movement, and check that it is the same as the mid point of the range shown on the inside elevator trim indicator.

 

 

[Guest pelorus32]

Fascinating thread. I am reminded of the accident in the US - a B1900 I think. The aircraft had been in for maintenance and the elevator controls were re-rigged. The person who did it was not qualified, it was not properly checked and there were errors in both how it was done and in the maintenance manual.

 

The aircraft then went back on line and flew a number of flights - I think around 20 hours - before the accident flight. On the accident flight the C of G was, by awful chance, the aftmost of any of the post maintenance flights. This meant that on takeoff there was insufficient forward elevator travel to manage the aft C of G. The aircraft pitched up, stalled and crashed.

 

The message for me is that a whole series of safety mechanisms failed and whilst there were some control position differences they were really too small to be reliably picked up. On the accident flight the particular circumstances combined with the maintenance failure to deliver a bad outcome.

 

Regards

 

Mike

 

 

[Guest Macnoz]

Hi

 

subscribers to this excellent thread might be interested in a post I made in the Jabiru thread regarding trim

 

http://www.recreationalflying.com/forum/showthread.php?t=7393

 

 

[Methusala]

Friend of mine flew in yesterday. Said he upon landing," I hadn't flown for a while and when taking off couldn't understand why it wouldn't rotate!". You've guessed it... didn't check the trim! Regards, Don.:;)4:

 

 

[crazy diamond]

I really am a sicko aren't I, can I see more pictures of the hangar? Looks like Bonanza graveyard in there!!! Oh well, I always use "Trim set for T/O" and check it before every departure. On another note when some aircraft I flew had come out of maintenance I'd insist the engineer who'd worked on it come with me if it was a post maint. flight.