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A B767-200 was dispatched with airspeed limit indications incorrectly repaired.
| Attributes | |
| ACN | 361392 |
| Time | |
| Date | 199611 |
| Day | Fri |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | airport : zzz |
| State Reference | US |
| Altitude | agl bound lower : 0 agl bound upper : 0 |
| Environment | |
| Light | Night |
| Aircraft 1 | |
| Operator | common carrier : air carrier |
| Make Model Name | B767-200 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other Other |
| Flight Phase | other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | other personnel other |
| Qualification | other other : other |
| ASRS Report | 361392 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | aircraft equipment problem : less severe non adherence : far non adherence : published procedure other anomaly other |
| Independent Detector | other flight crewa other other : unspecified cockpit |
| Resolutory Action | other |
| Consequence | Other |
| Supplementary | |
| Air Traffic Incident | other |
Narrative:
Air carrier xyz aircraft, a B767-222 was found to have a broken vmo- mmo switch guard by maintenance. The switch guard was not in stock at YYY so a deferred item was made. On nov/xx/96, this aircraft arrived ZZZ for overnight maintenance. I was given this item 'alternate vmo mmo switch in ee compartment switch guard broken off.' I ordered and received the switch guard from ZZZ stores department then went to the spot where aircraft was parked. The aircraft was being washed, the access stand was pulled away from the L1 door and power was off. I got a ladder and entered east&east through the lower access door. I removed the broken switch guard piece and compared the number on it with the new one and the ipc. The numbers matched. I installed the new guard and safetied the switch. I know now that the switch position must have been horizontal because in order to remove then tighten the nut the socket placed over the switch would change the switch position when engaging the nut. The switch guard is a 2 position guard that can be safetied in either position. At that time I did not realize that the position of the switch had changed. I signed off the item in the ready room, 'replaced switch guard. Checks ok.' aircraft left ZZZ that morning flight from ZZZ-YYY but diverted to XXX due to the captain's and first officer's vmo-mmo limit indicators both stuck at 265 KTS. Denver maintenance discovered the vmo-mmo switch guard closed and safetied. The switch was in the up or altitude position. Denver maintenance repositioned the switch to the normal position and the system checked ok. The flight from XXX to YYY noted normal operation. On nov/yy/96, I was informed by my foreman of this incident. I wrote a statement then we discussed the situation and concluded that because this switch can be safetied in either position, there is a potential for this mistake to be repeated. I briefed all mechanics at ZZZ maintenance about what happened and cautioned them to pay close attention when performing this task. About a week later I met with my team coordinator and we filled out a report detailing all the circumstances of this situation.
Original NASA ASRS Text
Title: A B767-200 WAS DISPATCHED WITH AIRSPD LIMIT INDICATIONS INCORRECTLY REPAIRED.
Narrative: ACR XYZ ACFT, A B767-222 WAS FOUND TO HAVE A BROKEN VMO- MMO SWITCH GUARD BY MAINT. THE SWITCH GUARD WAS NOT IN STOCK AT YYY SO A DEFERRED ITEM WAS MADE. ON NOV/XX/96, THIS ACFT ARRIVED ZZZ FOR OVERNIGHT MAINT. I WAS GIVEN THIS ITEM 'ALTERNATE VMO MMO SWITCH IN EE COMPARTMENT SWITCH GUARD BROKEN OFF.' I ORDERED AND RECEIVED THE SWITCH GUARD FROM ZZZ STORES DEPT THEN WENT TO THE SPOT WHERE ACFT WAS PARKED. THE ACFT WAS BEING WASHED, THE ACCESS STAND WAS PULLED AWAY FROM THE L1 DOOR AND PWR WAS OFF. I GOT A LADDER AND ENTERED E&E THROUGH THE LOWER ACCESS DOOR. I REMOVED THE BROKEN SWITCH GUARD PIECE AND COMPARED THE NUMBER ON IT WITH THE NEW ONE AND THE IPC. THE NUMBERS MATCHED. I INSTALLED THE NEW GUARD AND SAFETIED THE SWITCH. I KNOW NOW THAT THE SWITCH POS MUST HAVE BEEN HORIZ BECAUSE IN ORDER TO REMOVE THEN TIGHTEN THE NUT THE SOCKET PLACED OVER THE SWITCH WOULD CHANGE THE SWITCH POS WHEN ENGAGING THE NUT. THE SWITCH GUARD IS A 2 POS GUARD THAT CAN BE SAFETIED IN EITHER POS. AT THAT TIME I DID NOT REALIZE THAT THE POS OF THE SWITCH HAD CHANGED. I SIGNED OFF THE ITEM IN THE READY ROOM, 'REPLACED SWITCH GUARD. CHKS OK.' ACFT LEFT ZZZ THAT MORNING FLT FROM ZZZ-YYY BUT DIVERTED TO XXX DUE TO THE CAPT'S AND FO'S VMO-MMO LIMIT INDICATORS BOTH STUCK AT 265 KTS. DENVER MAINT DISCOVERED THE VMO-MMO SWITCH GUARD CLOSED AND SAFETIED. THE SWITCH WAS IN THE UP OR ALT POS. DENVER MAINT REPOSITIONED THE SWITCH TO THE NORMAL POS AND THE SYS CHKED OK. THE FLT FROM XXX TO YYY NOTED NORMAL OP. ON NOV/YY/96, I WAS INFORMED BY MY FOREMAN OF THIS INCIDENT. I WROTE A STATEMENT THEN WE DISCUSSED THE SIT AND CONCLUDED THAT BECAUSE THIS SWITCH CAN BE SAFETIED IN EITHER POS, THERE IS A POTENTIAL FOR THIS MISTAKE TO BE REPEATED. I BRIEFED ALL MECHS AT ZZZ MAINT ABOUT WHAT HAPPENED AND CAUTIONED THEM TO PAY CLOSE ATTN WHEN PERFORMING THIS TASK. ABOUT A WK LATER I MET WITH MY TEAM COORDINATOR AND WE FILLED OUT A RPT DETAILING ALL THE CIRCUMSTANCES OF THIS SIT.
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.