Narrative:

While approaching to land, the left seat pilot slowed the aircraft to approximately 10 mph below vlo down and extended the gear. I (right seat, flight instrument, chkout pilot) noticed the main gear light flickered on and off followed by the right main gear indicating both main gears were down and locked. Since the nose bulb was not lit, it appeared that the nose gear had no indication of being down and locked. The red gear warning light at the top of the control panel was lit and the gear horn sounded when the throttle was reduced. I (right seat flight instrument chkout pilot) initiated a go around and requested a heading of 270 degrees to depart the TCA and work on the landing gear problem. The tower gave me a heading of 210 degrees followed by a heading of 270 degrees and cleared me to maneuver west of the airport. The purpose of this flight was to provide a chkout for the left seat pilot in the small aircraft. All 3 occupants of the aircraft were certified flight instrs. However I was the only pilot with experience in this aft. Therefore when the incident occurred I took command of the aircraft and assigned the pilot in the back to handle all communications with ATC. I instructed the left seat pilot to read through the emergency gear extension checklist while I operated the controls. The left seat pilot and I worked through the checklist 3 times. We were unable to obtain an indication that the nose gear was down and locked. At this point I initiated steep turns, full stalls and abrupt yawing of the rudder. ATC vectored another aircraft past us to visually check if the gear was down. The pilot of the other aircraft said, 'it appears all 3 gear are down.' we requested ATC to contact the owner/operator of the aircraft to discuss any option we may not have considered. The owner/operator suggested an abrupt pull up at 120 KTS while simultaneously pushing the emergency gear extension knob down. We tried that twice and still had a red gear warning light and a horn. The owner/operator suggested I put both of the other pilots in the back seat. This would allow for their weight to be used to assist in holding the nose gear off the ground as long as possible in case the nose gear collapsed upon landing. ATC then vectored us toward the airport for a low fly-by. The owner/operator suggested a mechanic could see if the gear was down. After the fly-by the tower said, 'the gear is down. Make short approach. Cleared to land.' I notified tower that I still had a gear horn and I still wanted to do a precautionary landing. I was cleared to land. I did a long, slow approach and touched down as soft as possible, holding the nose gear off as long as possible and shut the engine off in the flare. I let the aircraft roll out and slow down on its own west/O touching the brakes. The propeller stopped horizontal prior to the aircraft coming to rest. I heard the tower ask if we could make the turnoff. I told the pilot operating the radio to inform them that we would need a tow off the runway. I was concerned that if I turned off, the gear might collapse. Since the horn was still going off, I shut the master off. The aircraft was taxied into a hangar and mechanics put it up on jacks. The gear was down and locked. The problem was a bolt located adjacent to the right side of the nose gear door that had vibrated loose. This bolt attaches the cowling to a bracket attached to the engine mount. Since the bolt was going the bracket slid back and rested against the gear down indicator on the nose gear. This is what caused the horn and the red light to stay on, as well as causing the gear pump to continue running. From this experience I realized how valuable cockpit resource management, crew coordination and communication are to a pilot. In the interest of safety and to prevent recurrence of this situation, the bolt should be inspected by an a & P mechanic at a regular interval.

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Original NASA ASRS Text

Title: MISSING BOLT ALLOWS COWLING TO INTERFERE WITH NOSE GEAR POSITION INDICATOR SWITCH, LEADING TO FALSE GEAR UNSAFE INDICATION FOR SMA AT CLT.

Narrative: WHILE APCHING TO LAND, THE LEFT SEAT PLT SLOWED THE ACFT TO APPROX 10 MPH BELOW VLO DOWN AND EXTENDED THE GEAR. I (RIGHT SEAT, FLT INSTR, CHKOUT PLT) NOTICED THE MAIN GEAR LIGHT FLICKERED ON AND OFF FOLLOWED BY THE RIGHT MAIN GEAR INDICATING BOTH MAIN GEARS WERE DOWN AND LOCKED. SINCE THE NOSE BULB WAS NOT LIT, IT APPEARED THAT THE NOSE GEAR HAD NO INDICATION OF BEING DOWN AND LOCKED. THE RED GEAR WARNING LIGHT AT THE TOP OF THE CTL PANEL WAS LIT AND THE GEAR HORN SOUNDED WHEN THE THROTTLE WAS REDUCED. I (RIGHT SEAT FLT INSTR CHKOUT PLT) INITIATED A GAR AND REQUESTED A HDG OF 270 DEGS TO DEPART THE TCA AND WORK ON THE LNDG GEAR PROB. THE TWR GAVE ME A HDG OF 210 DEGS FOLLOWED BY A HDG OF 270 DEGS AND CLRED ME TO MANEUVER W OF THE ARPT. THE PURPOSE OF THIS FLT WAS TO PROVIDE A CHKOUT FOR THE LEFT SEAT PLT IN THE SMA. ALL 3 OCCUPANTS OF THE ACFT WERE CERTIFIED FLT INSTRS. HOWEVER I WAS THE ONLY PLT WITH EXPERIENCE IN THIS AFT. THEREFORE WHEN THE INCIDENT OCCURRED I TOOK COMMAND OF THE ACFT AND ASSIGNED THE PLT IN THE BACK TO HANDLE ALL COMS WITH ATC. I INSTRUCTED THE LEFT SEAT PLT TO READ THROUGH THE EMER GEAR EXTENSION CHKLIST WHILE I OPERATED THE CTLS. THE LEFT SEAT PLT AND I WORKED THROUGH THE CHKLIST 3 TIMES. WE WERE UNABLE TO OBTAIN AN INDICATION THAT THE NOSE GEAR WAS DOWN AND LOCKED. AT THIS POINT I INITIATED STEEP TURNS, FULL STALLS AND ABRUPT YAWING OF THE RUDDER. ATC VECTORED ANOTHER ACFT PAST US TO VISUALLY CHK IF THE GEAR WAS DOWN. THE PLT OF THE OTHER ACFT SAID, 'IT APPEARS ALL 3 GEAR ARE DOWN.' WE REQUESTED ATC TO CONTACT THE OWNER/OPERATOR OF THE ACFT TO DISCUSS ANY OPTION WE MAY NOT HAVE CONSIDERED. THE OWNER/OPERATOR SUGGESTED AN ABRUPT PULL UP AT 120 KTS WHILE SIMULTANEOUSLY PUSHING THE EMER GEAR EXTENSION KNOB DOWN. WE TRIED THAT TWICE AND STILL HAD A RED GEAR WARNING LIGHT AND A HORN. THE OWNER/OPERATOR SUGGESTED I PUT BOTH OF THE OTHER PLTS IN THE BACK SEAT. THIS WOULD ALLOW FOR THEIR WT TO BE USED TO ASSIST IN HOLDING THE NOSE GEAR OFF THE GND AS LONG AS POSSIBLE IN CASE THE NOSE GEAR COLLAPSED UPON LNDG. ATC THEN VECTORED US TOWARD THE ARPT FOR A LOW FLY-BY. THE OWNER/OPERATOR SUGGESTED A MECH COULD SEE IF THE GEAR WAS DOWN. AFTER THE FLY-BY THE TWR SAID, 'THE GEAR IS DOWN. MAKE SHORT APCH. CLRED TO LAND.' I NOTIFIED TWR THAT I STILL HAD A GEAR HORN AND I STILL WANTED TO DO A PRECAUTIONARY LNDG. I WAS CLRED TO LAND. I DID A LONG, SLOW APCH AND TOUCHED DOWN AS SOFT AS POSSIBLE, HOLDING THE NOSE GEAR OFF AS LONG AS POSSIBLE AND SHUT THE ENG OFF IN THE FLARE. I LET THE ACFT ROLL OUT AND SLOW DOWN ON ITS OWN W/O TOUCHING THE BRAKES. THE PROP STOPPED HORIZ PRIOR TO THE ACFT COMING TO REST. I HEARD THE TWR ASK IF WE COULD MAKE THE TURNOFF. I TOLD THE PLT OPERATING THE RADIO TO INFORM THEM THAT WE WOULD NEED A TOW OFF THE RWY. I WAS CONCERNED THAT IF I TURNED OFF, THE GEAR MIGHT COLLAPSE. SINCE THE HORN WAS STILL GOING OFF, I SHUT THE MASTER OFF. THE ACFT WAS TAXIED INTO A HANGAR AND MECHS PUT IT UP ON JACKS. THE GEAR WAS DOWN AND LOCKED. THE PROB WAS A BOLT LOCATED ADJACENT TO THE RIGHT SIDE OF THE NOSE GEAR DOOR THAT HAD VIBRATED LOOSE. THIS BOLT ATTACHES THE COWLING TO A BRACKET ATTACHED TO THE ENG MOUNT. SINCE THE BOLT WAS GOING THE BRACKET SLID BACK AND RESTED AGAINST THE GEAR DOWN INDICATOR ON THE NOSE GEAR. THIS IS WHAT CAUSED THE HORN AND THE RED LIGHT TO STAY ON, AS WELL AS CAUSING THE GEAR PUMP TO CONTINUE RUNNING. FROM THIS EXPERIENCE I REALIZED HOW VALUABLE COCKPIT RESOURCE MGMNT, CREW COORD AND COM ARE TO A PLT. IN THE INTEREST OF SAFETY AND TO PREVENT RECURRENCE OF THIS SITUATION, THE BOLT SHOULD BE INSPECTED BY AN A & P MECH AT A REGULAR INTERVAL.

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.