Flight crew of an light transport overshot climb altitude due to autoplt problem distraction.

Attributes
ACN	320520
Time
Date	199511
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : aml airport : iad
State Reference	VA
Altitude	msl bound lower : 7000 msl bound upper : 7500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : iad tower : mbs
Operator	common carrier : air carrier
Make Model Name	Jetstream 41
Operating Under FAR Part	Part 135
Flight Phase	climbout : intermediate altitude
Route In Use	departure other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	other other : other pilot : instrument pilot : commercial pilot : atp
Experience	flight time last 90 days : 200 flight time total : 9000 flight time type : 600
ASRS Report	320520
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : cfi pilot : commercial pilot : instrument
Experience	flight time last 90 days : 230 flight time type : 230
ASRS Report	321154
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : overshoot non adherence : clearance other anomaly other
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

After departure we contacted iad departure controller. He cleared us to climb to 10000 ft. A moment later he cleared us for left turn direct csn VOR, own navigation, and amended the altitude to 7000 ft. At the time of his transmission our autoplt failed, producing a loud repeating bell. I cancelled this bell and read back the clearance as I had heard it. 'Left turn direct csn, own navigation, 10000 ft.' at 7500 ft, ATC asked about our altitude. I responded '7500 ft.' ATC response 'I thought I amended your altitude to 7000 ft.' I responded 'I didn't get that, we'll descend to 7000 ft.' ATC response 'just maintain 8000 ft.' the amended altitude clearance must have been masked by the loud bell from the failed autoplt. After I read back a clearance to 10000 ft and the controller did not challenge it, I was led to believe it was correct.

Original NASA ASRS Text

Title: FLC OF AN LTT OVERSHOT CLB ALT DUE TO AUTOPLT PROB DISTR.

Narrative: AFTER DEP WE CONTACTED IAD DEP CTLR. HE CLRED US TO CLB TO 10000 FT. A MOMENT LATER HE CLRED US FOR L TURN DIRECT CSN VOR, OWN NAV, AND AMENDED THE ALT TO 7000 FT. AT THE TIME OF HIS XMISSION OUR AUTOPLT FAILED, PRODUCING A LOUD REPEATING BELL. I CANCELLED THIS BELL AND READ BACK THE CLRNC AS I HAD HEARD IT. 'L TURN DIRECT CSN, OWN NAV, 10000 FT.' AT 7500 FT, ATC ASKED ABOUT OUR ALT. I RESPONDED '7500 FT.' ATC RESPONSE 'I THOUGHT I AMENDED YOUR ALT TO 7000 FT.' I RESPONDED 'I DIDN'T GET THAT, WE'LL DSND TO 7000 FT.' ATC RESPONSE 'JUST MAINTAIN 8000 FT.' THE AMENDED ALT CLRNC MUST HAVE BEEN MASKED BY THE LOUD BELL FROM THE FAILED AUTOPLT. AFTER I READ BACK A CLRNC TO 10000 FT AND THE CTLR DID NOT CHALLENGE IT, I WAS LED TO BELIEVE IT WAS CORRECT.

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.