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B737-300 first officer reports inadvertent start switch activation during preflight activities.
| Attributes | |
| ACN | 792675 |
| Time | |
| Date | 200806 |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | airport : zzz.airport |
| State Reference | US |
| Altitude | agl single value : 0 |
| Aircraft 1 | |
| Operator | common carrier : air carrier |
| Make Model Name | B737-300 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | ground : preflight |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Experience | flight time last 90 days : 200 flight time total : 9600 flight time type : 6600 |
| ASRS Report | 792675 |
| Events | |
| Anomaly | aircraft equipment problem : less severe |
| Independent Detector | other flight crewa |
| Supplementary | |
| Problem Areas | Aircraft Flight Crew Human Performance |
| Primary Problem | Ambiguous |
Narrative:
During preflight; upon returning from lavatory; I heard the captain yelling out the window to the ground crew. The discussion was about the #1 engine rotating. We had not yet accomplished any checklists and there was no intention to have an engine started. Upon review and discussion of the situation; the captain surmised that the #1 start switch must have been left in a partially activated position and her hand must have bumped it when she started the APU. We were both skeptical of such a possibility; so; during our regularly scheduled engine start; I first attempted to re-create the mis-positioned start switch; with success. So it is indeed feasible that the #1 start switch could have been slightly depressed and incompletely rotated prior to the APU start attempt. I did not notice either of the engine start switches out of position during my cockpit setup flows; nor do I remember specifically looking at them.callback conversation with reporter revealed the following information: the reporter believes that this is just the way the switch operates and was not defective. He has not tested this theory on other aircraft or other switches. No log book entry was made so maintenance did not have any input.
Original NASA ASRS Text
Title: B737-300 FO RPTS INADVERTENT START SWITCH ACTIVATION DURING PREFLIGHT ACTIVITIES.
Narrative: DURING PREFLT; UPON RETURNING FROM LAVATORY; I HEARD THE CAPT YELLING OUT THE WINDOW TO THE GND CREW. THE DISCUSSION WAS ABOUT THE #1 ENGINE ROTATING. WE HAD NOT YET ACCOMPLISHED ANY CHKLISTS AND THERE WAS NO INTENTION TO HAVE AN ENGINE STARTED. UPON REVIEW AND DISCUSSION OF THE SITUATION; THE CAPT SURMISED THAT THE #1 START SWITCH MUST HAVE BEEN LEFT IN A PARTIALLY ACTIVATED POSITION AND HER HAND MUST HAVE BUMPED IT WHEN SHE STARTED THE APU. WE WERE BOTH SKEPTICAL OF SUCH A POSSIBILITY; SO; DURING OUR REGULARLY SCHEDULED ENGINE START; I FIRST ATTEMPTED TO RE-CREATE THE MIS-POSITIONED START SWITCH; WITH SUCCESS. SO IT IS INDEED FEASIBLE THAT THE #1 START SWITCH COULD HAVE BEEN SLIGHTLY DEPRESSED AND INCOMPLETELY ROTATED PRIOR TO THE APU START ATTEMPT. I DID NOT NOTICE EITHER OF THE ENGINE START SWITCHES OUT OF POSITION DURING MY COCKPIT SETUP FLOWS; NOR DO I REMEMBER SPECIFICALLY LOOKING AT THEM.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR BELIEVES THAT THIS IS JUST THE WAY THE SWITCH OPERATES AND WAS NOT DEFECTIVE. HE HAS NOT TESTED THIS THEORY ON OTHER ACFT OR OTHER SWITCHES. NO LOG BOOK ENTRY WAS MADE SO MAINT DID NOT HAVE ANY INPUT.
Data retrieved from NASA's ASRS site as of May 2009 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.