A fatigued CE750 captain reported responding to an egpws terrain warning at 2;200 ft after mistakenl...

Attributes
ACN	987446
Time
Date	201201
Local Time Of Day	1801-2400
Place
Locale Reference	MMU.Airport
State Reference	NJ
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Make Model Name	Citation X (C750)
Operating Under FAR Part	Part 91
Flight Phase	Initial Approach
Flight Plan	IFR
Person 1
Function	Captain Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance Inflight Event / Encounter CFTT / CFIT

Narrative:

During the arrival phase we were descending from 3;000 ft to 2;000 ft when we received a terrain warning on the GPWS at 2;200 ft. We responded to the warning by climbing and the warning quickly ceased at about 2;500 ft. I asked approach control about our altitude assignment and he instructed us to return to 3;000 ft. He was very calm and pleasant throughout. I believe we mistakenly accepted a clearance issued to another aircraft which was descending into teb. It is likely that my readback was blocked and the controller was unaware of our descent. My lack of attentiveness may have been due to the onset of fatigue. We were delayed almost 3 hours leaving our departure airport because of heavy holiday departure traffic; resulting in a longer day than anticipated.

Original NASA ASRS Text

Title: A fatigued CE750 Captain reported responding to an EGPWS Terrain Warning at 2;200 FT after mistakenly taking an other aircraft's clearance when they should have been at 3;000 FT.

Narrative: During the arrival phase we were descending from 3;000 FT to 2;000 FT when we received a terrain warning on the GPWS at 2;200 FT. We responded to the warning by climbing and the warning quickly ceased at about 2;500 FT. I asked Approach Control about our altitude assignment and he instructed us to return to 3;000 FT. He was very calm and pleasant throughout. I believe we mistakenly accepted a clearance issued to another aircraft which was descending into TEB. It is likely that my readback was blocked and the Controller was unaware of our descent. My lack of attentiveness may have been due to the onset of fatigue. We were delayed almost 3 hours leaving our departure airport because of heavy holiday departure traffic; resulting in a longer day than anticipated.

Data retrieved from NASA's ASRS site as of July 2013 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.

A fatigued CE750 captain reported responding to an egpws terrain warning at 2;200 ft after mistakenly taking an other aircraft's clearance when they should have been at 3;000 ft.