Narrative:

Experienced severe vibration from engine/propeller. Requested vector to nearest airport from ZAB. Constant vibration caused reduction of power, loss of speed, altitude resulting in gear-up landing in approximately 18 mi at ft stockton, tx. Minor damage to 2 belly skins, propeller strike. No injuries to passenger. Vibration cause undetermined at this time. Callback conversation with reporter revealed the following information: the reporter stated that he had stopped, 20 mins previous to this event, at peq where he had refueled his 1963 vintage bonanza on his way home from a week-long trip to california. At first, he suspected fuel contamination but that was later ruled out as a cause. When the vibration started he immediately reduced power because he 'thought the propeller was going to fly off.' he praised ZAB's assistance in helping him avoid developing thunderstorms in his path and for pointing out the long, wide runway at fst which was off of his nose. He stated that he became so distraction by the vibration that he was 'rattled' to the point that he ignored the gear warning horn, thinking it was his stall warning horn. Apparently the same horn is wired to several system and, in his opinion, is ineffective. He suggested that the gear warning horn be a different sound, such as a warbling tone. The day after his gear up landing, the FAA arrived at fst and determined the situation to be an incident. The aircraft's propeller, a flowthorpe product, was replaced with a mccauley propeller and ferried to a beechcraft dealer. There was no engine vibration after the propeller was replaced which indicates the vibration may have had to do with propeller damage of some kind which has not yet been idented. Less than a yr earlier, the reporter had the engine overhauled and the propeller inspected. At that time, the a&P declared the propeller passed inspection and did not need further work. The reporter stated that the propeller had a lifetime guarantee and there were no airworthiness directives pending. He assumed it was a circa 1963 product, if not even earlier.

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Original NASA ASRS Text

Title: A BE35 PLT EXPERIENCED SIGNIFICANT ENG VIBRATION IN ZAB'S AIRSPACE, WHICH DISTR THE PLT SO MUCH THAT HE INADVERTENTLY LANDED GEAR UP AT HIS DIVERSION ARPT, FST.

Narrative: EXPERIENCED SEVERE VIBRATION FROM ENG/PROP. REQUESTED VECTOR TO NEAREST ARPT FROM ZAB. CONSTANT VIBRATION CAUSED REDUCTION OF PWR, LOSS OF SPD, ALT RESULTING IN GEAR-UP LNDG IN APPROX 18 MI AT FT STOCKTON, TX. MINOR DAMAGE TO 2 BELLY SKINS, PROP STRIKE. NO INJURIES TO PAX. VIBRATION CAUSE UNDETERMINED AT THIS TIME. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THAT HE HAD STOPPED, 20 MINS PREVIOUS TO THIS EVENT, AT PEQ WHERE HE HAD REFUELED HIS 1963 VINTAGE BONANZA ON HIS WAY HOME FROM A WK-LONG TRIP TO CALIFORNIA. AT FIRST, HE SUSPECTED FUEL CONTAMINATION BUT THAT WAS LATER RULED OUT AS A CAUSE. WHEN THE VIBRATION STARTED HE IMMEDIATELY REDUCED PWR BECAUSE HE 'THOUGHT THE PROP WAS GOING TO FLY OFF.' HE PRAISED ZAB'S ASSISTANCE IN HELPING HIM AVOID DEVELOPING TSTMS IN HIS PATH AND FOR POINTING OUT THE LONG, WIDE RWY AT FST WHICH WAS OFF OF HIS NOSE. HE STATED THAT HE BECAME SO DISTR BY THE VIBRATION THAT HE WAS 'RATTLED' TO THE POINT THAT HE IGNORED THE GEAR WARNING HORN, THINKING IT WAS HIS STALL WARNING HORN. APPARENTLY THE SAME HORN IS WIRED TO SEVERAL SYS AND, IN HIS OPINION, IS INEFFECTIVE. HE SUGGESTED THAT THE GEAR WARNING HORN BE A DIFFERENT SOUND, SUCH AS A WARBLING TONE. THE DAY AFTER HIS GEAR UP LNDG, THE FAA ARRIVED AT FST AND DETERMINED THE SIT TO BE AN INCIDENT. THE ACFT'S PROP, A FLOWTHORPE PRODUCT, WAS REPLACED WITH A MCCAULEY PROP AND FERRIED TO A BEECHCRAFT DEALER. THERE WAS NO ENG VIBRATION AFTER THE PROP WAS REPLACED WHICH INDICATES THE VIBRATION MAY HAVE HAD TO DO WITH PROP DAMAGE OF SOME KIND WHICH HAS NOT YET BEEN IDENTED. LESS THAN A YR EARLIER, THE RPTR HAD THE ENG OVERHAULED AND THE PROP INSPECTED. AT THAT TIME, THE A&P DECLARED THE PROP PASSED INSPECTION AND DID NOT NEED FURTHER WORK. THE RPTR STATED THAT THE PROP HAD A LIFETIME GUARANTEE AND THERE WERE NO AIRWORTHINESS DIRECTIVES PENDING. HE ASSUMED IT WAS A CIRCA 1963 PRODUCT, IF NOT EVEN EARLIER.

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.