Date: 201411
Local time of day: 0601-1200
Location: ZZZ.TRACON, US
Flight conditions: VMC
Light: Daylight
Aircraft: Medium Large Transport; Low Wing; 2 Turbojet Eng
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Climb
Airspace: Class B ZZZ
ATC / advisory: TRACON ZZZ
Aircraft component: Microphone
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Human factors: Situational Awareness
Second reporter function: Pilot Flying; Captain
Anomaly: Aircraft Equipment Problem Less Severe; Inflight Event / Encounter Other / Unknown
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Became Reoriented; Flight Crew Overcame Equipment Problem
Contributing factors: Aircraft; Equipment / Tooling
Primary problem: Ambiguous

Narrative: The taxi out and takeoff were routine and uneventful. We were flying an aircraft that had the new version of the ACP [Audio Control Panel] installed with the latching hot MIC function.  Upon our initial climbout at approximately 2200  MSL we were handed from Tower to Departure Control.  We made initial contact with Departure and were cleared to 12;000 feet.  We continued our climb and at some point our microphone became stuck. We were adhering to the sterile cockpit and at 10;000 feet the Captain (PF) called for the Climb Checklist. We ran the climb check and continued to climb and level at 12;000 feet.  At this time we had a small discussion about our Agent and how our initial loadsheet was incorrect and how the Agent had tried to justify his error on the original loadsheet. After a short period of time I started to question; to myself; why we hadn't gotten a further climb.  At that time I attempted to call Departure on COMM 1 and quickly realized that I was not receiving a response.  I attempted to switch to COMM 2 and at that time realized that we had a stuck MIC. Upon switching to COMM 2 we still had a stuck MIC; and I motioned to the Captain as such. He picked up my motions quickly as we had previously discussed how he had gotten a stuck MIC with his Bose headset. He then reached up and unplugged his headset and within a few seconds the stuck MIC was cleared. I then was able to contact departure on COMM 2 and he stated that he had been trying to call us but was unable but he could hear us. He then gave us a frequency change and we continued on. The rest of the flight continued with the Captain using a backup headset and I was using a Bose. No more stuck MICs were encountered on this flight. To the best of my knowledge no violation of the sterile cockpit was committed and no inappropriate language was used on the open MIC.


Second narrative: Climbing thru 2500 feet we were cleared to climb to 12;000 feet. We maintained sterile cockpit thru 10;000 feet; accomplished the climb check; and leveled off at 12;000 feet. Soon after that we started wondering if ATC had forgotten us; so we asked ATC about resuming our climb. That is when we realized we had a stuck MIC. The aircraft was outfitted with the new moisture proof COMM panels and we were using the locking interphone feature. We turned off these switches and tried VHF 2; but we still had an internal stuck MIC. I unplugged my headset from the aircraft; and soon after doing that the problem corrected. I am not sure how long we had a stuck MIC; but I don't believe we engaged in any inappropriate talk and I know we had a sterile cockpit. I did not make a logbook writeup as I believed the problem to be my personal headset and not an aircraft equipment problem.


Synopsis: Flight crew experiences a stuck mic during initial climb and attribute the problem to the combination of a new ACP and a Bose headset. When the headset is unplugged the stuck mic goes away.