Narrative:

At a friend's request, I was looking over his newly purchased used small aircraft with another CFI, who is also a mechanic. Owner asked us if we would like to fly it with him to see what we thought of it. We were considering using the aircraft eventually for our own personal use. Owner flew aircraft from left seat, with me in right seat and other CFI/mechanic in back seat. Owner made several takeoffs and lndgs, and we (both CFI's) noticed that his approachs were very steep and slow, with stall horn chirping for last 100' or so of descent. Lndgs were a little hard. He asked for advice. We offered that he should add a little speed and shallow his descent angle. He did, and a better landing resulted on next attempt. He offered me the controls, so I switched seats (with him) and me a scheduled for tower clearance to do a high speed taxi down the runway so I could get the feel of the aircraft. No takeoff clearance was asked for or issued. I accelerated down runway slowly to get used to it and allowed speed to increase gradually. As speed reached 70 mph, I closed the throttle and began to decelerate. Nose wheel must have lifted off, because it bounced and the aircraft began to porpoise. By the third porpoise it appeared I might run out of runway before I had the porpoising under control, so I added full power and rotated slightly. The unintentional takeoff seemed uneventful. Tower advised us that no takeoff clearance had been issued. I continued the pattern and demonstrated a landing which turned out to be a very good one. We taxied in and leaving the engine running changed pilots again. This time the CFI in back flew from left seat, with owner in right seat and me in back seat. He made a couple of lndgs/takeoffs, demonstrating the same landing attitude and speed/power G/south relationship I did. Changed pilots again, this time owner in left seat. He demonstrated a couple more takeoffs and lndgs and seemed to be satisfied, so we taxied back in and shut down. Post-flight inspection I did found propeller damage at tips. We could not believe it. We had not heard nor felt any impact nor any vibration. I feel the porpoising I did must have caused the contact. Worst of all, neither myself or the other CFI was current in small aircraft and the owner was a student pilot. I intended to taxi the aircraft and became airborne unintentionally as a reaction to a worsening situation. I had never scratched an airplane in 17 yrs and over 7000 hours as a professional corp pilot. I am not sure I can even count the # of judgement errors I committed. Lesson learned: good judgement is no accident! Flying a more sophisticated, more complex aircraft is not qualifying experience for any less complex aircraft. Get a good chkout by current and qualified CFI before you even taxi an unfamiliar aircraft--and certainly before flying or instructing in one.

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Original NASA ASRS Text

Title: SMA PORPOISED OUT OF CONTROL DURING HIGH SPEED TAXI TEST. INADVERTENT TKOF. PROPELLER DAMAGE.

Narrative: AT A FRIEND'S REQUEST, I WAS LOOKING OVER HIS NEWLY PURCHASED USED SMA WITH ANOTHER CFI, WHO IS ALSO A MECH. OWNER ASKED US IF WE WOULD LIKE TO FLY IT WITH HIM TO SEE WHAT WE THOUGHT OF IT. WE WERE CONSIDERING USING THE ACFT EVENTUALLY FOR OUR OWN PERSONAL USE. OWNER FLEW ACFT FROM LEFT SEAT, WITH ME IN RIGHT SEAT AND OTHER CFI/MECH IN BACK SEAT. OWNER MADE SEVERAL TKOFS AND LNDGS, AND WE (BOTH CFI'S) NOTICED THAT HIS APCHS WERE VERY STEEP AND SLOW, WITH STALL HORN CHIRPING FOR LAST 100' OR SO OF DSCNT. LNDGS WERE A LITTLE HARD. HE ASKED FOR ADVICE. WE OFFERED THAT HE SHOULD ADD A LITTLE SPD AND SHALLOW HIS DSCNT ANGLE. HE DID, AND A BETTER LNDG RESULTED ON NEXT ATTEMPT. HE OFFERED ME THE CONTROLS, SO I SWITCHED SEATS (WITH HIM) AND ME A SCHEDULED FOR TWR CLRNC TO DO A HIGH SPD TAXI DOWN THE RWY SO I COULD GET THE FEEL OF THE ACFT. NO TKOF CLRNC WAS ASKED FOR OR ISSUED. I ACCELERATED DOWN RWY SLOWLY TO GET USED TO IT AND ALLOWED SPD TO INCREASE GRADUALLY. AS SPD REACHED 70 MPH, I CLOSED THE THROTTLE AND BEGAN TO DECELERATE. NOSE WHEEL MUST HAVE LIFTED OFF, BECAUSE IT BOUNCED AND THE ACFT BEGAN TO PORPOISE. BY THE THIRD PORPOISE IT APPEARED I MIGHT RUN OUT OF RWY BEFORE I HAD THE PORPOISING UNDER CONTROL, SO I ADDED FULL PWR AND ROTATED SLIGHTLY. THE UNINTENTIONAL TKOF SEEMED UNEVENTFUL. TWR ADVISED US THAT NO TKOF CLRNC HAD BEEN ISSUED. I CONTINUED THE PATTERN AND DEMONSTRATED A LNDG WHICH TURNED OUT TO BE A VERY GOOD ONE. WE TAXIED IN AND LEAVING THE ENG RUNNING CHANGED PLTS AGAIN. THIS TIME THE CFI IN BACK FLEW FROM LEFT SEAT, WITH OWNER IN RIGHT SEAT AND ME IN BACK SEAT. HE MADE A COUPLE OF LNDGS/TKOFS, DEMONSTRATING THE SAME LNDG ATTITUDE AND SPD/PWR G/S RELATIONSHIP I DID. CHANGED PLTS AGAIN, THIS TIME OWNER IN LEFT SEAT. HE DEMONSTRATED A COUPLE MORE TKOFS AND LNDGS AND SEEMED TO BE SATISFIED, SO WE TAXIED BACK IN AND SHUT DOWN. POST-FLT INSPECTION I DID FOUND PROP DAMAGE AT TIPS. WE COULD NOT BELIEVE IT. WE HAD NOT HEARD NOR FELT ANY IMPACT NOR ANY VIBRATION. I FEEL THE PORPOISING I DID MUST HAVE CAUSED THE CONTACT. WORST OF ALL, NEITHER MYSELF OR THE OTHER CFI WAS CURRENT IN SMA AND THE OWNER WAS A STUDENT PLT. I INTENDED TO TAXI THE ACFT AND BECAME AIRBORNE UNINTENTIONALLY AS A REACTION TO A WORSENING SITUATION. I HAD NEVER SCRATCHED AN AIRPLANE IN 17 YRS AND OVER 7000 HRS AS A PROFESSIONAL CORP PLT. I AM NOT SURE I CAN EVEN COUNT THE # OF JUDGEMENT ERRORS I COMMITTED. LESSON LEARNED: GOOD JUDGEMENT IS NO ACCIDENT! FLYING A MORE SOPHISTICATED, MORE COMPLEX ACFT IS NOT QUALIFYING EXPERIENCE FOR ANY LESS COMPLEX ACFT. GET A GOOD CHKOUT BY CURRENT AND QUALIFIED CFI BEFORE YOU EVEN TAXI AN UNFAMILIAR ACFT--AND CERTAINLY BEFORE FLYING OR INSTRUCTING IN ONE.

Data retrieved from NASA's ASRS site as of August 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.