Narrative:

The purpose of one flight was dual instruction with special emphasis on emergency landing procedures. The WX was VFR, with gusty wind averaging about 15 KTS. We had already executed 2 simulated emergency lndgs (power off) that had gone well. We then entered one pattern at a local uncontrolled airport and shot 3 lndgs aiming for accuracy. The conditions were somewhat challenging because of gusty crossing conditions. After one third touch and go, just as I was turning crosswind, at about 600' AGL, the instrument pulled the power to simulate engine failure on takeoff. We banked steeply back to the airport while simultaneously lowering gear and flaps. Both of us were occupied with the task of plting the plane safely back to the airport and executing a downwind crosswind landing. It seems neither of us checked the 'gear safe' light. We landed and began rollout, which continued for about half the normal rollout distance. The aircraft then veered right off the runway and onto a taxiway. After it came to rest we exited hastily and found that the right gear had folded back into the well. Contributing factors: we had been practicing emergencys that had included having the gear warning horn sounding for several mins. Although neither of us are sure, the horn was probably sounding and we tuned it out, having already become habituated to it. It is possible that the gear leg did not lock because of the forces caused by the bank while it was in the process of extension. It was on the outside of the turn. The mechanic is investigating this and other possibilities. Moral of story: 1) unusual procedures practiced seldom open door for pilot error. 2) as always, do gump check before every landing. Callback conversation with reporter revealed the following: reporter quoted mechanics logbook entry as 'intermittent operation of main contactor and of warning horn.'

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Original NASA ASRS Text

Title: RIGHT MAIN GEAR COLLAPSED ON ROLL OUT AFTER LNDG.

Narrative: THE PURPOSE OF ONE FLT WAS DUAL INSTRUCTION WITH SPECIAL EMPHASIS ON EMER LNDG PROCS. THE WX WAS VFR, WITH GUSTY WIND AVERAGING ABOUT 15 KTS. WE HAD ALREADY EXECUTED 2 SIMULATED EMER LNDGS (PWR OFF) THAT HAD GONE WELL. WE THEN ENTERED ONE PATTERN AT A LCL UNCTLED ARPT AND SHOT 3 LNDGS AIMING FOR ACCURACY. THE CONDITIONS WERE SOMEWHAT CHALLENGING BECAUSE OF GUSTY XING CONDITIONS. AFTER ONE THIRD TOUCH AND GO, JUST AS I WAS TURNING XWIND, AT ABOUT 600' AGL, THE INSTR PULLED THE PWR TO SIMULATE ENG FAILURE ON TKOF. WE BANKED STEEPLY BACK TO THE ARPT WHILE SIMULTANEOUSLY LOWERING GEAR AND FLAPS. BOTH OF US WERE OCCUPIED WITH THE TASK OF PLTING THE PLANE SAFELY BACK TO THE ARPT AND EXECUTING A DOWNWIND XWIND LNDG. IT SEEMS NEITHER OF US CHKED THE 'GEAR SAFE' LIGHT. WE LANDED AND BEGAN ROLLOUT, WHICH CONTINUED FOR ABOUT HALF THE NORMAL ROLLOUT DISTANCE. THE ACFT THEN VEERED RIGHT OFF THE RWY AND ONTO A TXWY. AFTER IT CAME TO REST WE EXITED HASTILY AND FOUND THAT THE RIGHT GEAR HAD FOLDED BACK INTO THE WELL. CONTRIBUTING FACTORS: WE HAD BEEN PRACTICING EMERS THAT HAD INCLUDED HAVING THE GEAR WARNING HORN SOUNDING FOR SEVERAL MINS. ALTHOUGH NEITHER OF US ARE SURE, THE HORN WAS PROBABLY SOUNDING AND WE TUNED IT OUT, HAVING ALREADY BECOME HABITUATED TO IT. IT IS POSSIBLE THAT THE GEAR LEG DID NOT LOCK BECAUSE OF THE FORCES CAUSED BY THE BANK WHILE IT WAS IN THE PROCESS OF EXTENSION. IT WAS ON THE OUTSIDE OF THE TURN. THE MECH IS INVESTIGATING THIS AND OTHER POSSIBILITIES. MORAL OF STORY: 1) UNUSUAL PROCS PRACTICED SELDOM OPEN DOOR FOR PLT ERROR. 2) AS ALWAYS, DO GUMP CHK BEFORE EVERY LNDG. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: RPTR QUOTED MECHS LOGBOOK ENTRY AS 'INTERMITTENT OPERATION OF MAIN CONTACTOR AND OF WARNING HORN.'

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.