Narrative:

Aircraft just had annual 2 weeks ago. On approach to landing at ama (IFR flight plan in good VFR conditions) landing gear did not extend. Circuit breaker for landing gear kept tripping. Attempts at cycling gear failed. Emergency extension procedure per aircraft flight manual failed to extend the gear on first and second attempts. On third attempt, only main gear extended. Emergency was declared. Another attempt at emergency extension procedure also failed to bring down the nose gear. Finally, I was able to get the nose gear down by executing a deliberate controled stall, which apparently shook the gear loose and allowed it to fall in place. Tower fly-by confirmed gear down, and an uneventful landing was made. During the first few mins of troubleshooting the gear, I temporarily and inadvertently descended below MVA due to divided attention. This is already my second problem with the landing gear on the TB20. Whenever there is a small leak in the hydraulic system, the hydraulic pump for the landing gear system runs continuously until it burns out. This was the reason for my first landing gear problem 4 yrs ago. The reason for today's problem is yet to be determined by my mechanic, but the first problem could have been prevented by a simple annunciator light indicating the hydraulic pump kept running in-flight (which it should not). This would prevent premature burnout of the pump. Also, as evidenced by this incident, the emergency extension system might not be adequate to extend the nose gear if it is stuck in the 'up' position. My brief descent below MVA was another indication of the dangers of divided attention. Callback conversation with reporter revealed the following information: the reporter is also the owner of the aircraft. He described his landing gear problem as having to do with a bungee that was binding, therefore, not allowing the nose gear to free-fall. In his report, he had described having a problem with the landing gear 4 yrs ago. He just learned from his mechanic that the 2 issues are separate from each other. The analyst contacted the mechanic for further information and learned that trinidads are no more prone to landing gear problems than any other retractable gear aircraft. He stated that the pump has an airworthiness directive on it and that socata has recently changed pump manufacturers.

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Original NASA ASRS Text

Title: A RELATIVELY LOW TIME PLT, FLYING HIS TRINIDAD, MADE SEVERAL ATTEMPTS TO EXTEND HIS LNDG GEAR. DURING THE EMER EXTENSION, THE MAIN GEAR EXTENDED ON THE THIRD ATTEMPT. HOWEVER, THE NOSE GEAR WOULD NOT EXTEND UNTIL HE POPPED IT INTO PLACE BY PLACING THE ACFT IN A STALL.

Narrative: ACFT JUST HAD ANNUAL 2 WKS AGO. ON APCH TO LNDG AT AMA (IFR FLT PLAN IN GOOD VFR CONDITIONS) LNDG GEAR DID NOT EXTEND. CIRCUIT BREAKER FOR LNDG GEAR KEPT TRIPPING. ATTEMPTS AT CYCLING GEAR FAILED. EMER EXTENSION PROC PER ACFT FLT MANUAL FAILED TO EXTEND THE GEAR ON FIRST AND SECOND ATTEMPTS. ON THIRD ATTEMPT, ONLY MAIN GEAR EXTENDED. EMER WAS DECLARED. ANOTHER ATTEMPT AT EMER EXTENSION PROC ALSO FAILED TO BRING DOWN THE NOSE GEAR. FINALLY, I WAS ABLE TO GET THE NOSE GEAR DOWN BY EXECUTING A DELIBERATE CTLED STALL, WHICH APPARENTLY SHOOK THE GEAR LOOSE AND ALLOWED IT TO FALL IN PLACE. TWR FLY-BY CONFIRMED GEAR DOWN, AND AN UNEVENTFUL LNDG WAS MADE. DURING THE FIRST FEW MINS OF TROUBLESHOOTING THE GEAR, I TEMPORARILY AND INADVERTENTLY DSNDED BELOW MVA DUE TO DIVIDED ATTN. THIS IS ALREADY MY SECOND PROB WITH THE LNDG GEAR ON THE TB20. WHENEVER THERE IS A SMALL LEAK IN THE HYD SYS, THE HYD PUMP FOR THE LNDG GEAR SYS RUNS CONTINUOUSLY UNTIL IT BURNS OUT. THIS WAS THE REASON FOR MY FIRST LNDG GEAR PROB 4 YRS AGO. THE REASON FOR TODAY'S PROB IS YET TO BE DETERMINED BY MY MECH, BUT THE FIRST PROB COULD HAVE BEEN PREVENTED BY A SIMPLE ANNUNCIATOR LIGHT INDICATING THE HYD PUMP KEPT RUNNING INFLT (WHICH IT SHOULD NOT). THIS WOULD PREVENT PREMATURE BURNOUT OF THE PUMP. ALSO, AS EVIDENCED BY THIS INCIDENT, THE EMER EXTENSION SYS MIGHT NOT BE ADEQUATE TO EXTEND THE NOSE GEAR IF IT IS STUCK IN THE 'UP' POS. MY BRIEF DSCNT BELOW MVA WAS ANOTHER INDICATION OF THE DANGERS OF DIVIDED ATTN. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR IS ALSO THE OWNER OF THE ACFT. HE DESCRIBED HIS LNDG GEAR PROB AS HAVING TO DO WITH A BUNGEE THAT WAS BINDING, THEREFORE, NOT ALLOWING THE NOSE GEAR TO FREE-FALL. IN HIS RPT, HE HAD DESCRIBED HAVING A PROB WITH THE LNDG GEAR 4 YRS AGO. HE JUST LEARNED FROM HIS MECH THAT THE 2 ISSUES ARE SEPARATE FROM EACH OTHER. THE ANALYST CONTACTED THE MECH FOR FURTHER INFO AND LEARNED THAT TRINIDADS ARE NO MORE PRONE TO LNDG GEAR PROBS THAN ANY OTHER RETRACTABLE GEAR ACFT. HE STATED THAT THE PUMP HAS AN AIRWORTHINESS DIRECTIVE ON IT AND THAT SOCATA HAS RECENTLY CHANGED PUMP MANUFACTURERS.

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.