Narrative:

We were being radar vectored to a right base leg for a visibility approach to runway 33L. On base leg, I called for flaps 1 degree, then flaps 5 degrees. Turning approximately 5-6 mi final, I called for gear down, flaps 15 degrees and landing checklist. I noticed that 1 of the flap position indicators was at 1 degree and the other appeared to be moving toward 2 degrees. The captain positioned the flap lever to the 1 degree position. I asked if the flap position circuit breaker behind me about should high was popped out. Captain looked briefly and said he didn't see any circuit breaker out. Captain then told me to set my airspeed but at flaps 0 degrees reference speed. Captain then took control of the aircraft and instructed me to tell the tower to have the emergency equipment standing by, that we would be making a flaps up landing with a possible split flap condition. He then instructed me to turn the automatic brakes on to setting #3. We landed in the T/D zone, advised the tower that no further assistance was required, cleared the runway 1 taxiway past where we would have with a normal landing and taxied to the gate. During taxi-in, I looked closely at the circuit breaker panel behind my seat. I found that the trailing edge flap position indicator circuit breaker was popped out. I asked the captain if he wanted me to reset it and he said to wait, that we'd have maintenance check it at the gate. Maintenance met our flight. They reset the circuit breaker, cycled the flaps up and down to various positions, then back up again. Flaps operated normally each time. No leaks or other system discrepancies were found, and the aircraft was returned to service. Neither the captain nor I know when or why the trailing edge flap position indicator circuit breaker popped out. The only explanation I can come up with is the following: while at cruise, I slid my seat full aft and released my shoulder harness. In the process of retracting, the shoulder harness buckle may have flipped over the top of the seat back and hit the trailing edge flap position indicator circuit breaker, causing it to pop. There were a # of nicks on the circuit breaker panel around the trailing edge flap position indicator circuit breaker area. A solution to this problem would be to have either the aircraft operators or manufacturers install a removable clear plastic cover over the portion of the circuit breaker panel likely to be hit by shoulder harness retractions. Callback conversation with reporter revealed the following: this is the second flap position indicator report the reporter has sent to ASRS. He has not reported the problem to the assn safety committed, but will do so. He ways other aircraft made by this company have a circuit breaker guard, but this model does not.

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Original NASA ASRS Text

Title: ACR MLG MADE A 0 DEGREE FLAP LNDG BECAUSE THE LEFT TRAILING EDGE FLAP INDICATOR FAILED TO MOVE WHEN FLAPS WERE EXTENDED. POSTFLT INSPECTION REVEALED THE CB FOR THIS INDICATOR HAD POPPED OR BEEN HIT BY SHOULDER HARNESS WHEN HARNESS WAS RELEASED.

Narrative: WE WERE BEING RADAR VECTORED TO A RIGHT BASE LEG FOR A VIS APCH TO RWY 33L. ON BASE LEG, I CALLED FOR FLAPS 1 DEG, THEN FLAPS 5 DEGS. TURNING APPROX 5-6 MI FINAL, I CALLED FOR GEAR DOWN, FLAPS 15 DEGS AND LNDG CHKLIST. I NOTICED THAT 1 OF THE FLAP POS INDICATORS WAS AT 1 DEG AND THE OTHER APPEARED TO BE MOVING TOWARD 2 DEGS. THE CAPT POSITIONED THE FLAP LEVER TO THE 1 DEG POS. I ASKED IF THE FLAP POS CB BEHIND ME ABOUT SHOULD HIGH WAS POPPED OUT. CAPT LOOKED BRIEFLY AND SAID HE DIDN'T SEE ANY CB OUT. CAPT THEN TOLD ME TO SET MY AIRSPD BUT AT FLAPS 0 DEGS REF SPD. CAPT THEN TOOK CTL OF THE ACFT AND INSTRUCTED ME TO TELL THE TWR TO HAVE THE EMER EQUIP STANDING BY, THAT WE WOULD BE MAKING A FLAPS UP LNDG WITH A POSSIBLE SPLIT FLAP CONDITION. HE THEN INSTRUCTED ME TO TURN THE AUTO BRAKES ON TO SETTING #3. WE LANDED IN THE T/D ZONE, ADVISED THE TWR THAT NO FURTHER ASSISTANCE WAS REQUIRED, CLRED THE RWY 1 TXWY PAST WHERE WE WOULD HAVE WITH A NORMAL LNDG AND TAXIED TO THE GATE. DURING TAXI-IN, I LOOKED CLOSELY AT THE CB PANEL BEHIND MY SEAT. I FOUND THAT THE TRAILING EDGE FLAP POS INDICATOR CB WAS POPPED OUT. I ASKED THE CAPT IF HE WANTED ME TO RESET IT AND HE SAID TO WAIT, THAT WE'D HAVE MAINT CHK IT AT THE GATE. MAINT MET OUR FLT. THEY RESET THE CB, CYCLED THE FLAPS UP AND DOWN TO VARIOUS POSITIONS, THEN BACK UP AGAIN. FLAPS OPERATED NORMALLY EACH TIME. NO LEAKS OR OTHER SYS DISCREPANCIES WERE FOUND, AND THE ACFT WAS RETURNED TO SVC. NEITHER THE CAPT NOR I KNOW WHEN OR WHY THE TRAILING EDGE FLAP POS INDICATOR CB POPPED OUT. THE ONLY EXPLANATION I CAN COME UP WITH IS THE FOLLOWING: WHILE AT CRUISE, I SLID MY SEAT FULL AFT AND RELEASED MY SHOULDER HARNESS. IN THE PROCESS OF RETRACTING, THE SHOULDER HARNESS BUCKLE MAY HAVE FLIPPED OVER THE TOP OF THE SEAT BACK AND HIT THE TRAILING EDGE FLAP POS INDICATOR CB, CAUSING IT TO POP. THERE WERE A # OF NICKS ON THE CB PANEL AROUND THE TRAILING EDGE FLAP POS INDICATOR CB AREA. A SOLUTION TO THIS PROB WOULD BE TO HAVE EITHER THE ACFT OPERATORS OR MANUFACTURERS INSTALL A REMOVABLE CLEAR PLASTIC COVER OVER THE PORTION OF THE CB PANEL LIKELY TO BE HIT BY SHOULDER HARNESS RETRACTIONS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: THIS IS THE SECOND FLAP POS INDICATOR RPT THE RPTR HAS SENT TO ASRS. HE HAS NOT RPTED THE PROB TO THE ASSN SAFETY COMMITTED, BUT WILL DO SO. HE WAYS OTHER ACFT MADE BY THIS COMPANY HAVE A CB GUARD, BUT THIS MODEL DOES NOT.

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.