Flight crew descends through assigned altitude.

Attributes
ACN	303393
Time
Date	199504
Day	Thu
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : bfl
State Reference	WA
Altitude	msl bound lower : 8500 msl bound upper : 10000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : sea
Operator	common carrier : air taxi
Make Model Name	Cessna Citation Undifferentiated or Other Model
Operating Under FAR Part	Part 135
Flight Phase	cruise other descent other
Flight Plan	IFR
Person 1
Affiliation	company : air taxi
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 60 flight time total : 5000 flight time type : 300
ASRS Report	303393
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance flight crew : returned to intended course or assigned course other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We were on a flight from east washington to boeing field. ATC gave us a descent to 10000 ft which is standard on wbound flts to seattle. I was the PNF, so it was my job to run the descent checklist, get ATIS and give an arrival report via the radio to the medical dispatcher at bfi. I also handled communication with ATC. Before reaching 10000 ft I was called by the medical dispatcher, so I asked the captain if he would cover communication #1 which was tuned to ATC. He said that would be fine. The medical dispatcher informed me we would be quick turned for another airlift mission. When I tuned back to ATC, I received instructions to climb and maintain 10000 ft. The captain said I can't believe it did that! (He had descended to 8800 ft.) we then climbed back to 10000 ft. Contributing factors: we were held at 10000 ft much longer than normal and company traffic was right ahead of us and they had been cleared for a visual approach. We both had the same call sign (xx and they had xxa). Also, I was talking to the medical dispatcher and did not call 1000 ft above, 500 ft above and so on. Factors affecting performance: the captain knew we would be given a visual clearance to follow company traffic. It was clear and we were on a high, wide right downwind and had the airport in sight. It was late and there was little traffic. In the future we could have a policy to give our reports only when level at an assigned altitude.

Original NASA ASRS Text

Title: FLC DSNDS THROUGH ASSIGNED ALT.

Narrative: WE WERE ON A FLT FROM E WASHINGTON TO BOEING FIELD. ATC GAVE US A DSCNT TO 10000 FT WHICH IS STANDARD ON WBOUND FLTS TO SEATTLE. I WAS THE PNF, SO IT WAS MY JOB TO RUN THE DSCNT CHKLIST, GET ATIS AND GIVE AN ARR RPT VIA THE RADIO TO THE MEDICAL DISPATCHER AT BFI. I ALSO HANDLED COM WITH ATC. BEFORE REACHING 10000 FT I WAS CALLED BY THE MEDICAL DISPATCHER, SO I ASKED THE CAPT IF HE WOULD COVER COM #1 WHICH WAS TUNED TO ATC. HE SAID THAT WOULD BE FINE. THE MEDICAL DISPATCHER INFORMED ME WE WOULD BE QUICK TURNED FOR ANOTHER AIRLIFT MISSION. WHEN I TUNED BACK TO ATC, I RECEIVED INSTRUCTIONS TO CLB AND MAINTAIN 10000 FT. THE CAPT SAID I CAN'T BELIEVE IT DID THAT! (HE HAD DSNDED TO 8800 FT.) WE THEN CLBED BACK TO 10000 FT. CONTRIBUTING FACTORS: WE WERE HELD AT 10000 FT MUCH LONGER THAN NORMAL AND COMPANY TFC WAS RIGHT AHEAD OF US AND THEY HAD BEEN CLRED FOR A VISUAL APCH. WE BOTH HAD THE SAME CALL SIGN (XX AND THEY HAD XXA). ALSO, I WAS TALKING TO THE MEDICAL DISPATCHER AND DID NOT CALL 1000 FT ABOVE, 500 FT ABOVE AND SO ON. FACTORS AFFECTING PERFORMANCE: THE CAPT KNEW WE WOULD BE GIVEN A VISUAL CLRNC TO FOLLOW COMPANY TFC. IT WAS CLR AND WE WERE ON A HIGH, WIDE R DOWNWIND AND HAD THE ARPT IN SIGHT. IT WAS LATE AND THERE WAS LITTLE TFC. IN THE FUTURE WE COULD HAVE A POLICY TO GIVE OUR RPTS ONLY WHEN LEVEL AT AN ASSIGNED ALT.

Data retrieved from NASA's ASRS site as of July 2007 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.