Developing an inverted sense of humour
Scene: Macchi MB326/Impala type
Task: Impress other Flt instructor (in rear cockpit) during end of Fiscal Year hours burn-off staff continuation sortie.
Sequence: A mixture of high g aerobatics culminating in a Porteus Loop (flick roll through 360 degrees using full pro-spin at the top of a loop)
Difficulty experienced:
1. Failed to recover from flick entry to Porteus and entered high rotational inverted spin with accelerometer fluctuating between -3.9 and +4.4g (neg g conf by later fatigue meter readings)
2. Other Flt Instructor kept saying his goodbyes after checking me central (and chortling a bit) - as I'd signed for the airframe no doubt (robbo always did have a great sense of humus).
3. Having peaked out at 20,000ft we were now passing 8000ft and it was looking like a back-breaking neg g punch-out when it suddenly snap-recovered itself.
Post-Flight Engineering Revelations
Engs found that large tip-tank on port side hadn't had all its toe-in/toe-out shims replaced on the fore and the aft locating spigots plus the big jeezus torque nut in the middle hadn't been done up (during an in-the-shop NDI inspection some many flights prior). Tip-tank had displaced and rotated on the wing-tip during the pro-spin entry evolution. Evidence for that was witness-marks plus one grease-held shim stuffed back into the hole by its relocating spigot.
Complication:
The Fun police at the higher HQ banned Porteus loops meaning that I had to work up a whole new low-level aero
display. That airframe subsequently wouldn't do a symmetrical buzz/buffet/judder max-rate turn without flicking
violently so it couldn't be utilized for student flying. The experts tried for a year but couldn't cure it. Someone
decided that it would be good for checking out test-pilot's trouble-shooting skills so it got shipped off to
irritate a whole new genus of unsuspecting tyros.
Theory: Asymmetric negative g rolling overstress can cause permanent deformations within a wing's attachment
structure
Lessons Learnt
a. Thinking and conversing under cyclically fluctuating pos/neg g causes voice to rise to a high pitch
b. The oral contraceptive abortion-avoidance strategy of an invitational "Handing over" doesn't work in dodgy
situations unless the other party is dumb enough to say "taking over"
c. Difficult to come up with a witty riposte when other cockpit says: "I'm impressed. What did you call this again?"
d. Departing suddenly, unexpectedly and violently during a stock-standard manoeuvre can be disorienting. When the triply checked recovery controls position then fails to work... after about 2 minutes you are quite clueless.
e. Looking out at alternate wing-tips during such a ride is highly unrecommended.
f. NDI isn't always non-destructive