Narrative:

While visiting the bay area for an air show, I took a local base official for a jet 'fam' ride. Prior to departure, I asked for his experience and he claimed several hours in fighter type aircraft and felt comfortable with the prospect of doing some gentle maneuvers in this aircraft. I filed IFR. Takeoff and en route to an area off the coast were uneventful. Upon approaching the clearance limit I asked for and got a block of airspace (with an altitude block 10000-14000') to do some maneuvering in the aircraft. After demonstrating some of the aircraft capabilities I left the back seater do some flying. During 1 maneuver he got the aircraft (ended up) inverted, rolling and in deep stall buffet. At that point I regained control of the aircraft and recovered from the incipient stall. We were headed in an 80-90 degree inverted dive. I essentially completed a split-south and brought the aircraft straight and back again. Recovery took place at about 5000' MSL, well out of the assigned altitude block. I climbed back to assigned altitude and returned to base uneventfully. ATC never mentioned the altitude deviation. I believe this would not have happened if I had not been so generous in assuming this high time pilot was going to be able to fly my aircraft west/O difficulty just on the basis of his indication of his experience (the vast majority of which it turns out was flying multi-engine transport type aircraft). I was too eager to defer to his status and let him fly us into a potentially dangerous situation. Never take anyone else's experience for granted unless you have first hand knowledge of their true capability and currency.

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Original NASA ASRS Text

Title: SMT AEROBATIC PLT LET PASSENGER FLY ACFT IN ELEMENTARY MANEUVERS. HE PUT ACFT INTO UNCONTROLLED STALL AND BEFORE RECOVERING, ACFT EXITED AIRSPACE ASSIGNED FOR MANEUVERS.

Narrative: WHILE VISITING THE BAY AREA FOR AN AIR SHOW, I TOOK A LCL BASE OFFICIAL FOR A JET 'FAM' RIDE. PRIOR TO DEP, I ASKED FOR HIS EXPERIENCE AND HE CLAIMED SEVERAL HRS IN FIGHTER TYPE ACFT AND FELT COMFORTABLE WITH THE PROSPECT OF DOING SOME GENTLE MANEUVERS IN THIS ACFT. I FILED IFR. TKOF AND ENRTE TO AN AREA OFF THE COAST WERE UNEVENTFUL. UPON APCHING THE CLRNC LIMIT I ASKED FOR AND GOT A BLOCK OF AIRSPACE (WITH AN ALT BLOCK 10000-14000') TO DO SOME MANEUVERING IN THE ACFT. AFTER DEMONSTRATING SOME OF THE ACFT CAPABILITIES I LEFT THE BACK SEATER DO SOME FLYING. DURING 1 MANEUVER HE GOT THE ACFT (ENDED UP) INVERTED, ROLLING AND IN DEEP STALL BUFFET. AT THAT POINT I REGAINED CTL OF THE ACFT AND RECOVERED FROM THE INCIPIENT STALL. WE WERE HEADED IN AN 80-90 DEG INVERTED DIVE. I ESSENTIALLY COMPLETED A SPLIT-S AND BROUGHT THE ACFT STRAIGHT AND BACK AGAIN. RECOVERY TOOK PLACE AT ABOUT 5000' MSL, WELL OUT OF THE ASSIGNED ALT BLOCK. I CLBED BACK TO ASSIGNED ALT AND RETURNED TO BASE UNEVENTFULLY. ATC NEVER MENTIONED THE ALT DEVIATION. I BELIEVE THIS WOULD NOT HAVE HAPPENED IF I HAD NOT BEEN SO GENEROUS IN ASSUMING THIS HIGH TIME PLT WAS GOING TO BE ABLE TO FLY MY ACFT W/O DIFFICULTY JUST ON THE BASIS OF HIS INDICATION OF HIS EXPERIENCE (THE VAST MAJORITY OF WHICH IT TURNS OUT WAS FLYING MULTI-ENG TRANSPORT TYPE ACFT). I WAS TOO EAGER TO DEFER TO HIS STATUS AND LET HIM FLY US INTO A POTENTIALLY DANGEROUS SITUATION. NEVER TAKE ANYONE ELSE'S EXPERIENCE FOR GRANTED UNLESS YOU HAVE FIRST HAND KNOWLEDGE OF THEIR TRUE CAPABILITY AND CURRENCY.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.