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A B737-300 after landing using flaps 40 degrees the crew was unable to retract the flaps due to a loose electrical connector on the right flap position transmitter.
| Attributes | |
| ACN | 509627 |
| Time | |
| Date | 200104 |
| Day | Tue |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | airport : las.airport |
| State Reference | NV |
| Altitude | agl single value : 0 |
| Aircraft 1 | |
| Controlling Facilities | tower : ewr.tower |
| Operator | common carrier : air carrier |
| Make Model Name | B737-300 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | ground : taxi |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 200 flight time total : 9800 flight time type : 3500 |
| ASRS Report | 509627 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Events | |
| Anomaly | aircraft equipment problem : critical other anomaly other |
| Independent Detector | aircraft equipment other aircraft equipment : trailing edge flap pos. indicator other flight crewa other flight crewb |
| Resolutory Action | none taken : detected after the fact |
| Consequence | other |
| Supplementary | |
| Problem Areas | Maintenance Human Performance Aircraft |
| Primary Problem | Aircraft |
Narrative:
We made a normal flaps 40 degree landing on runway 25L in las. After clearing the runway, the first officer placed the flap handle in the up position per SOP and the flaps failed to retract. The hydraulic system and pressures were normal. Maintenance met the aircraft and were able to retract the flaps after bypassing the asymmetry protection circuit. The flap position indicator needles did not indicate any asymmetry. The mechanics checked the flap position transmitters and found that the right one had a 'slightly loose' cannon plug. They tightened the plug and the flaps operated normally through several cycles. Before tightening the cannon plug, the needles on the flap position indicator were vibrating slightly. Maintenance replaced the cockpit flap position indicator. I find it disconcerting that a single loose cannon plug, which according to maintenance is not safety wired, can disable the flaps.
Original NASA ASRS Text
Title: A B737-300 AFTER LNDG USING FLAPS 40 DEGS THE CREW WAS UNABLE TO RETRACT THE FLAPS DUE TO A LOOSE ELECTRICAL CONNECTOR ON THE R FLAP POS XMITTER.
Narrative: WE MADE A NORMAL FLAPS 40 DEG LNDG ON RWY 25L IN LAS. AFTER CLRING THE RWY, THE FO PLACED THE FLAP HANDLE IN THE UP POS PER SOP AND THE FLAPS FAILED TO RETRACT. THE HYD SYS AND PRESSURES WERE NORMAL. MAINT MET THE ACFT AND WERE ABLE TO RETRACT THE FLAPS AFTER BYPASSING THE ASYMMETRY PROTECTION CIRCUIT. THE FLAP POS INDICATOR NEEDLES DID NOT INDICATE ANY ASYMMETRY. THE MECHS CHKED THE FLAP POS XMITTERS AND FOUND THAT THE R ONE HAD A 'SLIGHTLY LOOSE' CANNON PLUG. THEY TIGHTENED THE PLUG AND THE FLAPS OPERATED NORMALLY THROUGH SEVERAL CYCLES. BEFORE TIGHTENING THE CANNON PLUG, THE NEEDLES ON THE FLAP POS INDICATOR WERE VIBRATING SLIGHTLY. MAINT REPLACED THE COCKPIT FLAP POS INDICATOR. I FIND IT DISCONCERTING THAT A SINGLE LOOSE CANNON PLUG, WHICH ACCORDING TO MAINT IS NOT SAFETY WIRED, CAN DISABLE THE FLAPS.
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.