BE200 pilot reported a headset problem contributed to his descending below cleared altitude when he ...

Attributes
ACN	1395732
Time
Date	201610
Local Time Of Day	1201-1800
Place
Locale Reference	MKE.TRACON
State Reference	WI
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Super King Air 200
Operating Under FAR Part	Part 91
Flight Phase	Descent
Route In Use	Vectors Visual Approach
Flight Plan	IFR
Component
Aircraft Component	Headset
Person 1
Function	Single Pilot Pilot Flying
Qualification	Flight Crew Commercial Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 45 Flight Crew Total 2857 Flight Crew Type 1293
Person 2
Function	Approach
Qualification	Air Traffic Control Fully Certified
Experience	Air Traffic Control Time Certified In Pos 1 (yrs) 11
Events
Anomaly	ATC Issue All Types Deviation - Altitude Overshoot Deviation - Procedural Clearance

Narrative:

I was descending per milwaukee approach instructions for landing. My headset uses batteries for noise attenuation and they failed without warning causing a loud disturbance. I thought I read back the instructions to 'descend to 2;000 feet; expedite through 2;800 feet. As always fly first and handle unusual problems later. It did not make sense to attempt to replace batteries while on the visual; in such a busy airspace. According to TRACON; I was told to expedite to 2;800 feet. This was a misunderstanding due to the radio noise/headset complication and as soon as notified I immediately ascended to 2;800 feet and then as directed; turned toward [destination] airport. During my phone call to TRACON; I mentioned my read back of what I thought were my instructions; but they made no mention of whether that could be heard on the tape or just the controller's instruction to expedite to 2;800 feet. I think this is important as I am always careful to read back instructions but never heard the controller correct my callback of 2;000 feet.I will from this point forward verify my callback for any instructions from ATC. I will also be careful to check the batteries in the headset before flights in the future as well.no aircraft were involved and no evasive action was needed from my aircraft. ATC gave me vectors away from possible towers until I could climb to 2;800 feet before turning back to the airport. At no time did my terrain warning activate.

Original NASA ASRS Text

Title: BE200 pilot reported a headset problem contributed to his descending below cleared altitude when he misunderstood an ATC clearance.

Narrative: I was descending per Milwaukee Approach instructions for landing. My headset uses batteries for noise attenuation and they failed without warning causing a loud disturbance. I thought I read back the instructions to 'descend to 2;000 feet; expedite through 2;800 feet. As always fly first and handle unusual problems later. It did not make sense to attempt to replace batteries while on the visual; in such a busy airspace. According to TRACON; I was told to expedite to 2;800 feet. This was a misunderstanding due to the radio noise/headset complication and as soon as notified I immediately ascended to 2;800 feet and then as directed; turned toward [destination] Airport. During my phone call to TRACON; I mentioned my read back of what I thought were my instructions; but they made no mention of whether that could be heard on the tape or just the Controller's instruction to expedite to 2;800 feet. I think this is important as I am always careful to read back instructions but never heard the Controller correct my callback of 2;000 feet.I will from this point forward verify my callback for any instructions from ATC. I will also be careful to check the batteries in the headset before flights in the future as well.No aircraft were involved and no evasive action was needed from my aircraft. ATC gave me vectors away from possible towers until I could climb to 2;800 feet before turning back to the airport. At no time did my terrain warning activate.

Data retrieved from NASA's ASRS site 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.