CE560 pilot reported receiving a low altitude alert from ATC when he misunderstood a clearance and d...

Attributes
ACN	1727300
Time
Date	201912
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Make Model Name	Citation Excel (C560XL)
Operating Under FAR Part	Part 91
Flight Phase	Initial Approach
Route In Use	Vectors
Flight Plan	IFR
Person 1
Function	Pilot Flying Single Pilot
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 134 Flight Crew Total 5000 Flight Crew Type 452
Events
Anomaly	ATC Issue All Types Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance Inflight Event / Encounter CFTT / CFIT
Miss Distance	Vertical 1000

Narrative:

I was piloting a cessna citation in the south part of ZZZ1 class B airspace. I was on an IFR flight plan and was in communication with approach control. From somewhere a few miles west of ZZZ2; I was told to turn to a heading of north and descend to 2;500'. After a short amount of time; I started to look at my charts thinking that was too low for my position. I recall the controller being busy; trying to reach an aircraft that did not respond; and was awaiting an opportunity to confirm my altitude; when the controller called my tail number and told me to immediately climb to 3500' as I was in the middle of antennas. I later listened to the tape; and ATC assigned us to 3;500'; but I understood 2;500'; and repeated back 2;500' twice. Despite saying 2;500' twice; the controller did not catch it.

Original NASA ASRS Text

Title: CE560 pilot reported receiving a low altitude alert from ATC when he misunderstood a clearance and descended 1000' lower than cleared.

Narrative: I was piloting a Cessna Citation in the south part of ZZZ1 Class B airspace. I was on an IFR flight plan and was in communication with Approach Control. From somewhere a few miles west of ZZZ2; I was told to turn to a heading of north and descend to 2;500'. After a short amount of time; I started to look at my charts thinking that was too low for my position. I recall the controller being busy; trying to reach an aircraft that did not respond; and was awaiting an opportunity to confirm my altitude; when the controller called my tail number and told me to immediately climb to 3500' as I was in the middle of antennas. I later listened to the tape; and ATC assigned us to 3;500'; but I understood 2;500'; and repeated back 2;500' twice. Despite saying 2;500' twice; the controller did not catch it.

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.