A ce-750 mis-set altimeter by exactly 1' descending through the transition altitude and descended 1;...

Attributes
ACN	916181
Time
Date	201010
Local Time Of Day	1201-1800
Place
Locale Reference	BFI.Airport
State Reference	WA
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Make Model Name	Citation X (C750)
Operating Under FAR Part	Part 135
Flight Phase	Descent
Route In Use	Vectors STAR OLM
Flight Plan	IFR
Component
Aircraft Component	Altimeter
Person 1
Function	First Officer Pilot Flying
Qualification	Flight Crew Instrument Flight Crew Flight Instructor Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 60 Flight Crew Total 3750 Flight Crew Type 1000
Person 2
Function	Pilot Not Flying Captain
Qualification	Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 400 Flight Crew Total 6500 Flight Crew Type 2500
Events
Anomaly	Deviation - Altitude Overshoot Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy

Narrative:

I was the pilot flying as first officer when the captain went off frequency to get ATIS. He then returned and we continued our descent on the OLM6 arrival into bfi. We were told to descend to 10;000 ft and cancel the 12;000/250 KTS crossing restriction at arvad. We continued down to 10;000 ft and at fourt we turned to a heading of 340 degrees for vectors to the ILS 13R into bfi. Once on the heading of 340 degrees approach asked us what our altitude was. We reported back that it was 10;000 ft. He told us our altitude was showing 9;000 ft. A 1;000 ft deviation. We then requested the correct altimeter setting. We realized our error was the incorrect altimeter setting. He then gave us a descent to 4;000 for which we corrected the altimeter and leveled off at the correct altitude of 4;000 ft with the correct altimeter setting.all checklists were followed on descent and I don't know how we had set the wrong altimeter setting. We were on seven hours of flying; icing was reported and I was concentrating on flying the airplane; watching for ice and following the altitude and speed restrictions on the arrival. I really need to pay attention to what the current altimeter is and not rely on the other pilot to hear/set the correct altimeter during our transition checklist. I had a print out of the weather which was 2 hours old; and it would have been a great resource if I had checked it. I didn't think about the altimeter setting being that far off on altitude.

Original NASA ASRS Text

Title: A CE-750 mis-set altimeter by exactly 1' descending through the transition altitude and descended 1;000 FT below their cleared altitude during the arrival to BFI.

Narrative: I was the pilot flying as First Officer when the Captain went off frequency to get ATIS. He then returned and we continued our descent on the OLM6 arrival into BFI. We were told to descend to 10;000 FT and cancel the 12;000/250 KTS crossing restriction at ARVAD. We continued down to 10;000 FT and at FOURT we turned to a heading of 340 degrees for vectors to the ILS 13R into BFI. Once on the heading of 340 degrees Approach asked us what our altitude was. We reported back that it was 10;000 FT. He told us our altitude was showing 9;000 FT. A 1;000 FT deviation. We then requested the correct altimeter setting. We realized our error was the incorrect altimeter setting. He then gave us a descent to 4;000 for which we corrected the altimeter and leveled off at the correct altitude of 4;000 FT with the correct altimeter setting.All checklists were followed on descent and I don't know how we had set the wrong altimeter setting. We were on seven hours of flying; icing was reported and I was concentrating on flying the airplane; watching for ice and following the altitude and speed restrictions on the arrival. I really need to pay attention to what the current altimeter is and not rely on the other pilot to hear/set the correct altimeter during our transition checklist. I had a print out of the weather which was 2 hours old; and it would have been a great resource if I had checked it. I didn't think about the altimeter setting being that far off on altitude.

Data retrieved from NASA's ASRS site as of April 2012 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 ce-750 mis-set altimeter by exactly 1' descending through the transition altitude and descended 1;000 ft below their cleared altitude during the arrival to bfi.