Narrative:

The flight originated as an IFR round robin mission between teb and mmu airports. The purpose of the flight was to perform a functional check of the aircraft following an annual inspection. The flight departed teb on an IFR flight plan to mmu. An ILS runway 23 approach was executed with a touch and go followed by a transition back to teb for a VOR runway 24 approach. The approach was completed followed by a touch and go for a transition back to mmu to check out erratic OM, localizer, and G/south indications during the previous ILS. I was cleared for the approach and as I xed the OM on the mmu ILS runway 23 approach course the audible portion of the OM became extremely loud. It was also during this time that I was completing my final approach checklist. I attempted to mute the audible signal with the mute button below the marker beacon lights but was not readily successful. I then shut off the audible signal by using the appropriate switch on the audio panel. By this time I was well into the approach, in approach confign, with flaps and gear apparently extended. By habit, I rechked gear down and locked in the final phases of every approach and I believe that I did so at the time also. I recall believing that I saw 3 green! I also recall thinking that the approach speed was faster than usual for the power setting and the confign, although I could not fathom the reason at the time. At no time was there a gear warning horn or any other indication that the landing gear was not extended. Further power reductions in order to reduce airspeed did not trigger any gear warnings through the throttle/gear warning system. Approximately 10 seconds prior to impact, tower advised that the gear was not extended. I attempted to arrest the glide and flare and applied power in an attempt to escape the situation. However, the aircraft settled onto the runway. The aircraft came to rest slightly to the right of the centerline. All systems were shut down and the aircraft evacuated through the cabin door. I am not sure as to whether this was an event that was related to mechanical or human performance, or both. However, I do believe that the intensity of the OM audible may have caused enough distraction so as not to have noticed the classic gear transit sounds associated with this aircraft, or the absence of the same. In addition, such distraction may have also contributed to the interruption of the final approach checklist procedure, with the inadvertent assumption that all systems and controls had been properly set. Nonetheless, this incident was avoidable! Had the practice of tower alerting the pilot to 'check gear down and locked' when cleared to land been in effect, the incident may not have occurred. Also, the use of a concave mirror installed on the right hand side of the left nacelle on this aircraft, would provide a visibility means of verifying that the landing gear is extended. Finally, the gear warning system should be integrated into the airspeed indicating system so that operations below 120 KTS with gear retracted will trigger gear unsafe indications.

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Original NASA ASRS Text

Title: GA SMT GEAR UP LNDG AT MMU.

Narrative: THE FLT ORIGINATED AS AN IFR ROUND ROBIN MISSION BTWN TEB AND MMU ARPTS. THE PURPOSE OF THE FLT WAS TO PERFORM A FUNCTIONAL CHK OF THE ACFT FOLLOWING AN ANNUAL INSPECTION. THE FLT DEPARTED TEB ON AN IFR FLT PLAN TO MMU. AN ILS RWY 23 APCH WAS EXECUTED WITH A TOUCH AND GO FOLLOWED BY A TRANSITION BACK TO TEB FOR A VOR RWY 24 APCH. THE APCH WAS COMPLETED FOLLOWED BY A TOUCH AND GO FOR A TRANSITION BACK TO MMU TO CHK OUT ERRATIC OM, LOC, AND G/S INDICATIONS DURING THE PREVIOUS ILS. I WAS CLRED FOR THE APCH AND AS I XED THE OM ON THE MMU ILS RWY 23 APCH COURSE THE AUDIBLE PORTION OF THE OM BECAME EXTREMELY LOUD. IT WAS ALSO DURING THIS TIME THAT I WAS COMPLETING MY FINAL APCH CHKLIST. I ATTEMPTED TO MUTE THE AUDIBLE SIGNAL WITH THE MUTE BUTTON BELOW THE MARKER BEACON LIGHTS BUT WAS NOT READILY SUCCESSFUL. I THEN SHUT OFF THE AUDIBLE SIGNAL BY USING THE APPROPRIATE SWITCH ON THE AUDIO PANEL. BY THIS TIME I WAS WELL INTO THE APCH, IN APCH CONFIGN, WITH FLAPS AND GEAR APPARENTLY EXTENDED. BY HABIT, I RECHKED GEAR DOWN AND LOCKED IN THE FINAL PHASES OF EVERY APCH AND I BELIEVE THAT I DID SO AT THE TIME ALSO. I RECALL BELIEVING THAT I SAW 3 GREEN! I ALSO RECALL THINKING THAT THE APCH SPD WAS FASTER THAN USUAL FOR THE PWR SETTING AND THE CONFIGN, ALTHOUGH I COULD NOT FATHOM THE REASON AT THE TIME. AT NO TIME WAS THERE A GEAR WARNING HORN OR ANY OTHER INDICATION THAT THE LNDG GEAR WAS NOT EXTENDED. FURTHER PWR REDUCTIONS IN ORDER TO REDUCE AIRSPD DID NOT TRIGGER ANY GEAR WARNINGS THROUGH THE THROTTLE/GEAR WARNING SYS. APPROX 10 SECS PRIOR TO IMPACT, TWR ADVISED THAT THE GEAR WAS NOT EXTENDED. I ATTEMPTED TO ARREST THE GLIDE AND FLARE AND APPLIED PWR IN AN ATTEMPT TO ESCAPE THE SITUATION. HOWEVER, THE ACFT SETTLED ONTO THE RWY. THE ACFT CAME TO REST SLIGHTLY TO THE R OF THE CTRLINE. ALL SYSTEMS WERE SHUT DOWN AND THE ACFT EVACUATED THROUGH THE CABIN DOOR. I AM NOT SURE AS TO WHETHER THIS WAS AN EVENT THAT WAS RELATED TO MECHANICAL OR HUMAN PERFORMANCE, OR BOTH. HOWEVER, I DO BELIEVE THAT THE INTENSITY OF THE OM AUDIBLE MAY HAVE CAUSED ENOUGH DISTR SO AS NOT TO HAVE NOTICED THE CLASSIC GEAR TRANSIT SOUNDS ASSOCIATED WITH THIS ACFT, OR THE ABSENCE OF THE SAME. IN ADDITION, SUCH DISTR MAY HAVE ALSO CONTRIBUTED TO THE INTERRUPTION OF THE FINAL APCH CHKLIST PROC, WITH THE INADVERTENT ASSUMPTION THAT ALL SYSTEMS AND CTLS HAD BEEN PROPERLY SET. NONETHELESS, THIS INCIDENT WAS AVOIDABLE! HAD THE PRACTICE OF TWR ALERTING THE PLT TO 'CHK GEAR DOWN AND LOCKED' WHEN CLRED TO LAND BEEN IN EFFECT, THE INCIDENT MAY NOT HAVE OCCURRED. ALSO, THE USE OF A CONCAVE MIRROR INSTALLED ON THE R HAND SIDE OF THE L NACELLE ON THIS ACFT, WOULD PROVIDE A VIS MEANS OF VERIFYING THAT THE LNDG GEAR IS EXTENDED. FINALLY, THE GEAR WARNING SYSTEM SHOULD BE INTEGRATED INTO THE AIRSPD INDICATING SYS SO THAT OPS BELOW 120 KTS WITH GEAR RETRACTED WILL TRIGGER GEAR UNSAFE INDICATIONS.

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.