Poor handling characteristics of a specific aircraft
I hope you don't mind me using this forum to pick a few brains on a handling problem.
We're busy getting a turbine Dakota into flying condition after long term storage. The aircraft had its first flight a few weeks ago, and the pilot reported major handling problems. Unfortunately I wasn't able to have a detailed discussion with him, but he basically reported that the aircraft tried to roll over, and that it seemed sluggish. This particular pilot has a lot of time on type, and stated it was the worst handling he had ever experienced. Some of the "old hands" have said that this particular aircraft suffered from handling problems years ago, but we have found no official record of problems in the logbooks.
So far we have checked the following:
Control surfaces, positions and cable tensions - correct
Cable runs, pulleys etc - correct
Airspeed indicators - correct
Engine torque instruments - correct
The interesting one was the aircraft symmetry. When we measured, we found that the vertical fin was leaning over slightly. The angle of lean was fairly small, but we have now removed this and replaced the fin in the vertical. We also replaced a wingtip which was slightly out of alignment, although it was strictly speaking within tolerances.
The rest of the structure appears to be within specification. I also checked for any signs of structural deformation under load, but there were no signs of any buckled panels, popped rivets or similar damage.
The offset fin may have caused some handling problems, but my gut feel is that the offset was not enough to cause the major problems encountered. I am concerned that there is something else.
If you were faced with this problem, where would you look? What would you suggest as extra checks?
Blue Skies
StressMerchant