Last week I was asked by a fellow member and AP/IA (who will remain anonymous and who we will all refrain from criticizing) to come provide an aircraft check-out "for insurance purposes" . His airplane has been a several-year MAJOR restoration with an engine conversion and many, many other mods, all with either STC or field approvals. The new engine had been "ground-run" only, and this would be it's first flight.
I flew to his private field and looked the airplane over and while not-yet ready for "show" it appeared very airworthy with only a few issues after I pre-flighted it. (A few loose fasteners in the upper flap rollers and a couple other minor issues, which were quickly satisfied.) I confirmed the annual inspection was completed and signed off, with "approval for return to service."
We took it airborne and remained directly over the field at high power settings and speed (for cooling) for an hour, watched the CHT drop off about 50 degrees in about 30-40 mins, and then returned for a landing. A second takeoff/landing was made and was uneventful.
A postflight showed no major leaks and all was fine. It was lunchtime and with another local pilot, we all hopped into my airplane and went over to a nearby larger airport with a cafe for lunch. After lunch we returned and prepared for currency-checkout of 3 TO/LNDgs/stalls/etc..
First TO was cacelled during taxi due to rough throttle movement during power application. A check under the hood showed the castellated nut on the carb-lever had no cotter and the bolt had backed out and was rubbing the carb body.
The AP/IA owner blushed
and after that was corrected we made a second effort and the takeoff roll resulted in a reject due to fluctuating prop RPM. A static runup only resulted in the prop going to redline and then surging between redline and 300 RPM lower, repeatedly. Taxi back and take a look at the prop gov lever, and find another castellated nut with no cotter had fallen off. More
Corrected that and more thorough look/see at everything under the hood and off we go again. Climb to 5K and do a clean stall. Beautiful. Now for a dirty-stall. Beautiful....except the flaps won't retract but partially. Decided not to change a thing and descend and land with about 30-degrees flaps.
Postflight shows left flap loosey-goosey as usual and right flap jammed with inboard, lower roller-bolt fractured at threads with the roller jammed sideways in the track. (New-appearance AN bolt but all the threads are missing and the nut/threaded portion is down inside the flap.) Since this will require additional investigation/repair and since 3 takeoffs/landings have been accomplished by this very experienced tailwheel-qualified owner/pilot/AP/IA...it's decided to call it quits and he, with considerable embarrassment, admits he's looked at this airplane so much for the last several years he no longer trusts himself and promises to get another to inspect it before further flight.
Moral? Major restorations might need a different set of eyeballs before return-to-service. Or four.