Coopere
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- Feb 11, 2015
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I'm hoping someone with a vast amount of knowledge can yield some advise.
I have an 1968 Piper aztec d model.
Situation,
My aztec is in for annual.
My issue:
Ok, so when my Aztec goes in for annual and is in a heated hangar for say 5 days at 78f, we completed all gear swings and everything checks out just fine. Then she is pushed outside into the snow in very cold temperatures say below 15f heading down too 0f and if she sits say 5 days, the gear doors start to sag and close up. If I jump in and select gear down and use the manual gear extension pump I normally get between 1 and 3 pumps before the gear handle pops back to neutral and the gear doors are back to the normal position.
In the summer I never have any issue, their are no visual leaks. I'm thinking the gear doors are closing up due to contraction of the hydraulic fluid from it being at around 75f then cooling to below 15f
My question is this when they contract or sag, if I i kneel infront of the gear I can see that the gear strut won't clear the doors if gear up was selected.
I see in my service manual that their is a timing or priority valve that when gear down is selected it ports fluid to the gear door actuators prior to moving the gear, but no mention of what happens when gear up is selected. Does the timing valve make Sure the gear doors are open before swinging gear up?
I have seen the doors sag (they close up about 3 inches, not much but enough that it looks like the gear strut would clip the door if gear was selected up)
Only when the plane goes from very warm to very cold ie from maintenance heated hangar to cold conditions (32f and below) the bigger the temp swing the more they sag
To make darn sure I don't end up with a gear failure, I've been watching for this issue and select gear down after startup and prior to movement of the aircraft if I see the gear doors sagged in the walk around. Usually the handle pops to neutral after a couple seconds.
For reference I tried selecting gear down last summer once just to see how quick the handle returns to neutral and it was instantaneous.
Any advise?
I have an 1968 Piper aztec d model.
Situation,
My aztec is in for annual.
My issue:
Ok, so when my Aztec goes in for annual and is in a heated hangar for say 5 days at 78f, we completed all gear swings and everything checks out just fine. Then she is pushed outside into the snow in very cold temperatures say below 15f heading down too 0f and if she sits say 5 days, the gear doors start to sag and close up. If I jump in and select gear down and use the manual gear extension pump I normally get between 1 and 3 pumps before the gear handle pops back to neutral and the gear doors are back to the normal position.
In the summer I never have any issue, their are no visual leaks. I'm thinking the gear doors are closing up due to contraction of the hydraulic fluid from it being at around 75f then cooling to below 15f
My question is this when they contract or sag, if I i kneel infront of the gear I can see that the gear strut won't clear the doors if gear up was selected.
I see in my service manual that their is a timing or priority valve that when gear down is selected it ports fluid to the gear door actuators prior to moving the gear, but no mention of what happens when gear up is selected. Does the timing valve make Sure the gear doors are open before swinging gear up?
I have seen the doors sag (they close up about 3 inches, not much but enough that it looks like the gear strut would clip the door if gear was selected up)
Only when the plane goes from very warm to very cold ie from maintenance heated hangar to cold conditions (32f and below) the bigger the temp swing the more they sag
To make darn sure I don't end up with a gear failure, I've been watching for this issue and select gear down after startup and prior to movement of the aircraft if I see the gear doors sagged in the walk around. Usually the handle pops to neutral after a couple seconds.
For reference I tried selecting gear down last summer once just to see how quick the handle returns to neutral and it was instantaneous.
Any advise?
