Narrative:

In 10/88 I flew from smitty field, near washington, il, to st charles county airport, north of st charles, mo, with 1 passenger in my privately owned small aircraft. I called 3SZ tower approximately 20 mi north and was told to expect a straight in approach to runway 18. I called in on a 5 mi final as instructed and was cleared for the straight in approach. There was on other aircraft in the pattern. At about 4 mi out on final I lowered the gear and observed a green light. I completed the checklist, planning to use 75 mph on final approach and a full flap landing. I reduced power to idle on short final and touched down on the centerline at about 68 mph. I caught a light gust and the aircraft skipped slightly, probably a foot in the air. I cracked the throttle momentarily and again reduced to idle. The second T/D was light and also on the centerline. After I lowered the nose gear to the runway, I saw the gear handle start to move towards the aft (gear up) position and simultaneously heard the gear unsafe horn go off. I grabbed the handle and tried to stop its movement, but couldn't. The gear folded up under the aircraft at 55-60 mph and the aircraft came to rest on the runway, still on the center line. I immediately exited the aircraft with my passenger. Neither of us were hurt in any way. With the help of maintenance personnel at the airport, we raised the aircraft, put the gear back down and towed it to the hangar. The aircraft sustained damage to the propeller and had scrape marks on the nose wheel fairing and on some skin panels near the main gear wells, but did not appear to be significantly damaged. I have 2 partners in the aircraft, both private pilots with about 400 hours of flying experience in various aircraft. I am an air carrier first officer with approximately 7000 hours of flying time as pilot and an additional 4000 hours as a F/east, most of it in large, complex jet aircraft. I have a total of 160 hours in various small transport aircraft, almost all of it in models with electric gear. The aircraft in question had the old style manual gear and was the first of this type I had ever flown. I had about 4 1/2 hours in this airplane, including 6 lndgs. I was checked out in the airplane by one of my partners, who had owned the airplane with various others for about 5 yrs. The chkout consisted of a short flight around the local area and 1 landing. Since this aircraft differed from other small transport's I had experience in only in the operation of the gear, my partner/check pilot felt this was sufficient. The gear mechanism on this aircraft is generally regarded as sturdy and reliable. When the gear is down, the handle is all the way forward against the instrument panel with a sliding hand grip that lifts up into a socket and locks into position, tripping the gear green light and silencing the gear horn. To raise the gear, you unlock the sliding handle, slide it down out of the socket and rotate the lever back and down so that it ends up on the floor with the handle again held it place in a socket. The gear up socket does not have a locking mechanism. The question now is how did this event happen and what factors contributed to it. The first possibility is that the uplock failed after T/D allowing the gear to fold up as the weight of the airplane settled on it. While there has not yet been a detailed inspection of the gear mechanism, this does not appear to be the case. After raising the airplane and lowering the gear, everything appeared to work just as it is supposed to. That leaves the other possibility of human error. When I lowered the gear, it looked normal and sounded normal. I thought then and I still think that I saw a green light, but the mechanism is not supposed to work that way. It may be possible to push the handle up into its socket and just trip the green light, but not have it fully locked or it may be that I saw what I expected to see when it wasn't really there. If this is what happened, why did it happen? I feel there are basically 2 contributing factors. #1 is my long experience with air carrier jet aircraft. With well maintained, high quality equipment, you move smooth operating switches or levers and large pieces of equipment move into position. If they fail, there are at least 2 and frequently 3 experienced pilots observing. The warnings are loud and highly visible. You get used to a single movement of a control operating relays that cause a whole series of events to take place in the aircraft system. The control always works the way it is supposed to and you then look for a possible malfunction in the system. The small transport is very different. It is a simple mechanical linkage that takes a certain amount of effort and requires an awkward and somewhat complicated physical movement to complete. The control is the whole system. I just wasn't adequately prepared for the possibility that the movement of the control itself could cause a problem and that failure to complete the last 1/2' of that movement could defeat the whole mechanism. The other factor is, as it is so often is, training. On my chkout, I told my partner to assume I knew nothing and show me how to do it. I am not proud, and am perfectly willing to be taught and to learn. Nevertheless, the chkout was very brief and the fact that it is easy to make a mistake with this type of gear was not emphasized. In conversation with my partners later, they admitted that they felt it would be totally inappropriate for them to try to teach an airline pilot how to fly and as a result, they felt a little responsibility for what happened. In this, of course, they are totally wrong. I should have known that this psychology might have been active and taken more positive steps to ensure a more complete chkout. I should have emphasized that where light airplanes are concerned, I am the low timer and they are the experienced veterans and that I would rely on their training and knowledge to keep me out of trouble.

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Original NASA ASRS Text

Title: GEAR COLLAPSE AFTER LNDG.

Narrative: IN 10/88 I FLEW FROM SMITTY FIELD, NEAR WASHINGTON, IL, TO ST CHARLES COUNTY ARPT, N OF ST CHARLES, MO, WITH 1 PAX IN MY PRIVATELY OWNED SMA. I CALLED 3SZ TWR APPROX 20 MI N AND WAS TOLD TO EXPECT A STRAIGHT IN APCH TO RWY 18. I CALLED IN ON A 5 MI FINAL AS INSTRUCTED AND WAS CLRED FOR THE STRAIGHT IN APCH. THERE WAS ON OTHER ACFT IN THE PATTERN. AT ABOUT 4 MI OUT ON FINAL I LOWERED THE GEAR AND OBSERVED A GREEN LIGHT. I COMPLETED THE CHKLIST, PLANNING TO USE 75 MPH ON FINAL APCH AND A FULL FLAP LNDG. I REDUCED PWR TO IDLE ON SHORT FINAL AND TOUCHED DOWN ON THE CENTERLINE AT ABOUT 68 MPH. I CAUGHT A LIGHT GUST AND THE ACFT SKIPPED SLIGHTLY, PROBABLY A FOOT IN THE AIR. I CRACKED THE THROTTLE MOMENTARILY AND AGAIN REDUCED TO IDLE. THE SECOND T/D WAS LIGHT AND ALSO ON THE CENTERLINE. AFTER I LOWERED THE NOSE GEAR TO THE RWY, I SAW THE GEAR HANDLE START TO MOVE TOWARDS THE AFT (GEAR UP) POS AND SIMULTANEOUSLY HEARD THE GEAR UNSAFE HORN GO OFF. I GRABBED THE HANDLE AND TRIED TO STOP ITS MOVEMENT, BUT COULDN'T. THE GEAR FOLDED UP UNDER THE ACFT AT 55-60 MPH AND THE ACFT CAME TO REST ON THE RWY, STILL ON THE CENTER LINE. I IMMEDIATELY EXITED THE ACFT WITH MY PAX. NEITHER OF US WERE HURT IN ANY WAY. WITH THE HELP OF MAINT PERSONNEL AT THE ARPT, WE RAISED THE ACFT, PUT THE GEAR BACK DOWN AND TOWED IT TO THE HANGAR. THE ACFT SUSTAINED DAMAGE TO THE PROP AND HAD SCRAPE MARKS ON THE NOSE WHEEL FAIRING AND ON SOME SKIN PANELS NEAR THE MAIN GEAR WELLS, BUT DID NOT APPEAR TO BE SIGNIFICANTLY DAMAGED. I HAVE 2 PARTNERS IN THE ACFT, BOTH PVT PLTS WITH ABOUT 400 HRS OF FLYING EXPERIENCE IN VARIOUS ACFT. I AM AN ACR F/O WITH APPROX 7000 HRS OF FLYING TIME AS PLT AND AN ADDITIONAL 4000 HRS AS A F/E, MOST OF IT IN LARGE, COMPLEX JET ACFT. I HAVE A TOTAL OF 160 HRS IN VARIOUS SMT ACFT, ALMOST ALL OF IT IN MODELS WITH ELECTRIC GEAR. THE ACFT IN QUESTION HAD THE OLD STYLE MANUAL GEAR AND WAS THE FIRST OF THIS TYPE I HAD EVER FLOWN. I HAD ABOUT 4 1/2 HRS IN THIS AIRPLANE, INCLUDING 6 LNDGS. I WAS CHKED OUT IN THE AIRPLANE BY ONE OF MY PARTNERS, WHO HAD OWNED THE AIRPLANE WITH VARIOUS OTHERS FOR ABOUT 5 YRS. THE CHKOUT CONSISTED OF A SHORT FLT AROUND THE LCL AREA AND 1 LNDG. SINCE THIS ACFT DIFFERED FROM OTHER SMT'S I HAD EXPERIENCE IN ONLY IN THE OPERATION OF THE GEAR, MY PARTNER/CHK PLT FELT THIS WAS SUFFICIENT. THE GEAR MECHANISM ON THIS ACFT IS GENERALLY REGARDED AS STURDY AND RELIABLE. WHEN THE GEAR IS DOWN, THE HANDLE IS ALL THE WAY FORWARD AGAINST THE INSTRUMENT PANEL WITH A SLIDING HAND GRIP THAT LIFTS UP INTO A SOCKET AND LOCKS INTO POS, TRIPPING THE GEAR GREEN LIGHT AND SILENCING THE GEAR HORN. TO RAISE THE GEAR, YOU UNLOCK THE SLIDING HANDLE, SLIDE IT DOWN OUT OF THE SOCKET AND ROTATE THE LEVER BACK AND DOWN SO THAT IT ENDS UP ON THE FLOOR WITH THE HANDLE AGAIN HELD IT PLACE IN A SOCKET. THE GEAR UP SOCKET DOES NOT HAVE A LOCKING MECHANISM. THE QUESTION NOW IS HOW DID THIS EVENT HAPPEN AND WHAT FACTORS CONTRIBUTED TO IT. THE FIRST POSSIBILITY IS THAT THE UPLOCK FAILED AFTER T/D ALLOWING THE GEAR TO FOLD UP AS THE WT OF THE AIRPLANE SETTLED ON IT. WHILE THERE HAS NOT YET BEEN A DETAILED INSPECTION OF THE GEAR MECHANISM, THIS DOES NOT APPEAR TO BE THE CASE. AFTER RAISING THE AIRPLANE AND LOWERING THE GEAR, EVERYTHING APPEARED TO WORK JUST AS IT IS SUPPOSED TO. THAT LEAVES THE OTHER POSSIBILITY OF HUMAN ERROR. WHEN I LOWERED THE GEAR, IT LOOKED NORMAL AND SOUNDED NORMAL. I THOUGHT THEN AND I STILL THINK THAT I SAW A GREEN LIGHT, BUT THE MECHANISM IS NOT SUPPOSED TO WORK THAT WAY. IT MAY BE POSSIBLE TO PUSH THE HANDLE UP INTO ITS SOCKET AND JUST TRIP THE GREEN LIGHT, BUT NOT HAVE IT FULLY LOCKED OR IT MAY BE THAT I SAW WHAT I EXPECTED TO SEE WHEN IT WASN'T REALLY THERE. IF THIS IS WHAT HAPPENED, WHY DID IT HAPPEN? I FEEL THERE ARE BASICALLY 2 CONTRIBUTING FACTORS. #1 IS MY LONG EXPERIENCE WITH ACR JET ACFT. WITH WELL MAINTAINED, HIGH QUALITY EQUIP, YOU MOVE SMOOTH OPERATING SWITCHES OR LEVERS AND LARGE PIECES OF EQUIP MOVE INTO POS. IF THEY FAIL, THERE ARE AT LEAST 2 AND FREQUENTLY 3 EXPERIENCED PLTS OBSERVING. THE WARNINGS ARE LOUD AND HIGHLY VISIBLE. YOU GET USED TO A SINGLE MOVEMENT OF A CONTROL OPERATING RELAYS THAT CAUSE A WHOLE SERIES OF EVENTS TO TAKE PLACE IN THE ACFT SYS. THE CONTROL ALWAYS WORKS THE WAY IT IS SUPPOSED TO AND YOU THEN LOOK FOR A POSSIBLE MALFUNCTION IN THE SYS. THE SMT IS VERY DIFFERENT. IT IS A SIMPLE MECHANICAL LINKAGE THAT TAKES A CERTAIN AMOUNT OF EFFORT AND REQUIRES AN AWKWARD AND SOMEWHAT COMPLICATED PHYSICAL MOVEMENT TO COMPLETE. THE CONTROL IS THE WHOLE SYS. I JUST WASN'T ADEQUATELY PREPARED FOR THE POSSIBILITY THAT THE MOVEMENT OF THE CONTROL ITSELF COULD CAUSE A PROB AND THAT FAILURE TO COMPLETE THE LAST 1/2' OF THAT MOVEMENT COULD DEFEAT THE WHOLE MECHANISM. THE OTHER FACTOR IS, AS IT IS SO OFTEN IS, TRNING. ON MY CHKOUT, I TOLD MY PARTNER TO ASSUME I KNEW NOTHING AND SHOW ME HOW TO DO IT. I AM NOT PROUD, AND AM PERFECTLY WILLING TO BE TAUGHT AND TO LEARN. NEVERTHELESS, THE CHKOUT WAS VERY BRIEF AND THE FACT THAT IT IS EASY TO MAKE A MISTAKE WITH THIS TYPE OF GEAR WAS NOT EMPHASIZED. IN CONVERSATION WITH MY PARTNERS LATER, THEY ADMITTED THAT THEY FELT IT WOULD BE TOTALLY INAPPROPRIATE FOR THEM TO TRY TO TEACH AN AIRLINE PLT HOW TO FLY AND AS A RESULT, THEY FELT A LITTLE RESPONSIBILITY FOR WHAT HAPPENED. IN THIS, OF COURSE, THEY ARE TOTALLY WRONG. I SHOULD HAVE KNOWN THAT THIS PSYCHOLOGY MIGHT HAVE BEEN ACTIVE AND TAKEN MORE POSITIVE STEPS TO ENSURE A MORE COMPLETE CHKOUT. I SHOULD HAVE EMPHASIZED THAT WHERE LIGHT AIRPLANES ARE CONCERNED, I AM THE LOW TIMER AND THEY ARE THE EXPERIENCED VETERANS AND THAT I WOULD RELY ON THEIR TRNING AND KNOWLEDGE TO KEEP ME OUT OF TROUBLE.

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.