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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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First officer removes oxygen mask on capts return to cockpit but microphone selector switch remained on oxygen mask. Clearance acknowledgement not heard by controller. Altitude deviation.
| Attributes | |
| ACN | 198304 |
| Time | |
| Date | 199112 |
| Day | Fri |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : rzs |
| State Reference | CA |
| Altitude | msl bound lower : 28000 msl bound upper : 29000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Dusk |
| Aircraft 1 | |
| Controlling Facilities | artcc : zla |
| Operator | common carrier : air carrier |
| Make Model Name | Medium Large Transport, Low Wing, 2 Turbojet Eng |
| Navigation In Use | Other Other |
| Flight Phase | cruise other |
| Route In Use | enroute : on vectors |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : flight engineer pilot : atp |
| Experience | flight time last 90 days : 210 flight time total : 8000 flight time type : 210 |
| ASRS Report | 198304 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : commercial pilot : instrument pilot : flight engineer pilot : atp |
| Experience | flight time last 90 days : 215 flight time total : 15000 flight time type : 6500 |
| ASRS Report | 197411 |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other |
| Independent Detector | other flight crewa |
| Resolutory Action | flight crew : returned to intended course or assigned course |
| Consequence | faa : reviewed incident with flight crew |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
We were on a vector to rzs at FL280. I had just come off oxygen because the captain had been out of the cockpit. I was flying. The captain was on PA when lax ATC cleared us to FL310 (I thought). I acknowledged and began a climb. My side tone sounded muted but I thought it was interference from the PA amp. The captain finished PA and I repeated clearance to him. Center cleared us direct rzs, the captain acknowledged and center then asked our altitude. We replied FL290 for 310. Center told us to maintain FL280 and that the clearance was heading 310 to rzs not climb to FL310! We descended quickly back to FL280 and I discovered I had not returned my microphone selector switch back from oxygen position to boom! In the oxygen position the yoke switch will key only the oxygen mask and not the boom microphone. The switch is located below the right side window. Out of sight! Out of mind! Supplemental information from acn 197411. The copilot acknowledged this (remember his microphone switch out of position) as a climb to FL310. We had earlier asked for higher due to light/occ moderate chop at FL280.
Original NASA ASRS Text
Title: FO REMOVES OXYGEN MASK ON CAPTS RETURN TO COCKPIT BUT MIC SELECTOR SWITCH REMAINED ON OXYGEN MASK. CLRNC ACKNOWLEDGEMENT NOT HEARD BY CTLR. ALTDEV.
Narrative: WE WERE ON A VECTOR TO RZS AT FL280. I HAD JUST COME OFF OXYGEN BECAUSE THE CAPT HAD BEEN OUT OF THE COCKPIT. I WAS FLYING. THE CAPT WAS ON PA WHEN LAX ATC CLRED US TO FL310 (I THOUGHT). I ACKNOWLEDGED AND BEGAN A CLB. MY SIDE TONE SOUNDED MUTED BUT I THOUGHT IT WAS INTERFERENCE FROM THE PA AMP. THE CAPT FINISHED PA AND I REPEATED CLRNC TO HIM. CENTER CLRED US DIRECT RZS, THE CAPT ACKNOWLEDGED AND CENTER THEN ASKED OUR ALT. WE REPLIED FL290 FOR 310. CENTER TOLD US TO MAINTAIN FL280 AND THAT THE CLRNC WAS HDG 310 TO RZS NOT CLB TO FL310! WE DSNDED QUICKLY BACK TO FL280 AND I DISCOVERED I HAD NOT RETURNED MY MIC SELECTOR SWITCH BACK FROM OXYGEN POS TO BOOM! IN THE OXYGEN POS THE YOKE SWITCH WILL KEY ONLY THE OXYGEN MASK AND NOT THE BOOM MIC. THE SWITCH IS LOCATED BELOW THE R SIDE WINDOW. OUT OF SIGHT! OUT OF MIND! SUPPLEMENTAL INFO FROM ACN 197411. THE COPLT ACKNOWLEDGED THIS (REMEMBER HIS MIC SWITCH OUT OF POS) AS A CLB TO FL310. WE HAD EARLIER ASKED FOR HIGHER DUE TO LIGHT/OCC MODERATE CHOP AT FL280.
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.