Air carrier flight crew were unable to communicate with each other after they had donned their oxyge...

Attributes
ACN	115521
Time
Date	198906
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : pwm
State Reference	ME
Altitude	msl bound lower : 10000 msl bound upper : 10000
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	climbout : intermediate altitude
Route In Use	enroute airway : zbw
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 100 flight time total : 12100 flight time type : 1500
ASRS Report	115521
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : less severe aircraft equipment problem : critical
Independent Detector	other flight crewa
Resolutory Action	flight crew : declared emergency flight crew : overcame equipment problem
Consequence	Other
Supplementary
Primary Problem	Aircraft

Narrative:

Climbing through approximately 10,000' following a routine departure from portland, me, we experienced a sudden failure of the left engine causing the aircraft to shutter and fill both the cockpit and the passenger compartment with smoke. The captain was hand flying the aircraft at the time of the incident. We were both using boom microphone headsets with our aircraft speakers turned off. As I donned my mask, my headset was knocked from my head. The captain removed his before placing his mask on his head. This combination of equipment usage and switch position caused a temporary communication problem between the captain and myself, and with myself, and with ATC. I was unable to hear his commands other than a muffled noise coming from the left seat. With the smoke and all else that was occurring we were not immediately aware of the cause of our inability to communicate. We were fortunate to have the luxury of altitude and time. However, under other circumstances, this delay in establishing communications could be the difference between an incident and an accident. I would suggest a modification to the system such that donning the oxygen mask would automatically override switch and volume positions placing the mask microphone on line and the speaker volume to a comfortable usable listening level. This particular aircraft mask system would seem to lend itself easily to this modification. A switch/relay combination could be incorporated into the cover doors of the mask. When the mask is removed, the switch/relay combination would activate overriding the microphone switch and the speaker volume to the correct positions if necessary. With the requirement for the utilization of the boom microphone/headset or headset below 10,000' this will more than likely be an ongoing problem unless corrective measures are taken.

Original NASA ASRS Text

Title: ACR FLT CREW WERE UNABLE TO COMMUNICATE WITH EACH OTHER AFTER THEY HAD DONNED THEIR OXYGEN MASKS BECAUSE THE FO HAD INADVERTENTLY KNOCKED HIS HEADSET OFF AND DID NOT KNOW THIS HAD HAPPENED.

Narrative: CLIMBING THROUGH APPROX 10,000' FOLLOWING A ROUTINE DEP FROM PORTLAND, ME, WE EXPERIENCED A SUDDEN FAILURE OF THE LEFT ENGINE CAUSING THE ACFT TO SHUTTER AND FILL BOTH THE COCKPIT AND THE PASSENGER COMPARTMENT WITH SMOKE. THE CAPT WAS HAND FLYING THE ACFT AT THE TIME OF THE INCIDENT. WE WERE BOTH USING BOOM MIC HEADSETS WITH OUR ACFT SPEAKERS TURNED OFF. AS I DONNED MY MASK, MY HEADSET WAS KNOCKED FROM MY HEAD. THE CAPT REMOVED HIS BEFORE PLACING HIS MASK ON HIS HEAD. THIS COMBINATION OF EQUIPMENT USAGE AND SWITCH POSITION CAUSED A TEMPORARY COM PROBLEM BETWEEN THE CAPT AND MYSELF, AND WITH MYSELF, AND WITH ATC. I WAS UNABLE TO HEAR HIS COMMANDS OTHER THAN A MUFFLED NOISE COMING FROM THE LEFT SEAT. WITH THE SMOKE AND ALL ELSE THAT WAS OCCURRING WE WERE NOT IMMEDIATELY AWARE OF THE CAUSE OF OUR INABILITY TO COMMUNICATE. WE WERE FORTUNATE TO HAVE THE LUXURY OF ALT AND TIME. HOWEVER, UNDER OTHER CIRCUMSTANCES, THIS DELAY IN ESTABLISHING COMS COULD BE THE DIFFERENCE BETWEEN AN INCIDENT AND AN ACCIDENT. I WOULD SUGGEST A MODIFICATION TO THE SYSTEM SUCH THAT DONNING THE OXYGEN MASK WOULD AUTOMATICALLY OVERRIDE SWITCH AND VOLUME POSITIONS PLACING THE MASK MIC ON LINE AND THE SPEAKER VOLUME TO A COMFORTABLE USABLE LISTENING LEVEL. THIS PARTICULAR ACFT MASK SYSTEM WOULD SEEM TO LEND ITSELF EASILY TO THIS MODIFICATION. A SWITCH/RELAY COMBINATION COULD BE INCORPORATED INTO THE COVER DOORS OF THE MASK. WHEN THE MASK IS REMOVED, THE SWITCH/RELAY COMBINATION WOULD ACTIVATE OVERRIDING THE MIKE SWITCH AND THE SPEAKER VOLUME TO THE CORRECT POSITIONS IF NECESSARY. WITH THE REQUIREMENT FOR THE UTILIZATION OF THE BOOM MIC/HEADSET OR HEADSET BELOW 10,000' THIS WILL MORE THAN LIKELY BE AN ONGOING PROBLEM UNLESS CORRECTIVE MEASURES ARE TAKEN.

Data retrieved from NASA's ASRS site as of August 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.

Air carrier flight crew were unable to communicate with each other after they had donned their oxygen masks because the first officer had inadvertently knocked his headset off and did not know this had happened.