Altitude deviation altitude overshot in descent. Clearance interpretation readback hearback problem.

Attributes
ACN	252287
Time
Date	199309
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : bae
State Reference	WI
Altitude	msl bound lower : 32000 msl bound upper : 35000
Environment
Flight Conditions	Mixed
Light	Dusk
Aircraft 1
Controlling Facilities	artcc : zau
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	cruise other descent other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 200 flight time total : 6500 flight time type : 2450
ASRS Report	252287
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 188 flight time total : 18000 flight time type : 1374
ASRS Report	252286
Events
Anomaly	altitude deviation : overshoot altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance flight crew : returned to intended course or assigned course other
Consequence	faa : reviewed incident with flight crew faa : investigated
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation
Situations
ATC Facility	procedure or policy : unspecified

Narrative:

ZAU, on frequency 132.22, instructed our aircraft to descend to FL350, 'expedite through FL370' on a heading of 330 degrees for the descent. In order to increase our normal rate of descent, as requested by the controller, I manually intervened on the MCP IAS/mach window to increase our normal descent speed, thereby increasing the aircraft's rate of descent. A short time later, the controller asked what altitude we were descending through. The captain replied that we were descending through FL380. The controller then immediately issued a heading change to 290 degrees. At this time the frequency was very busy and congested. The controller was issuing numerous instructions to our aircraft and others on the frequency in a very short time period. The controller then instructed us to, what we thought to be at that time, a descent to FL290. The captain acknowledged the descent on the radio and I entered 29000 into the altitude window of the MCP. The captain verified my entry and entered FL290 into the crz altitude space of the FMC crz page. Descending through approximately FL320 the controller instructed us to climb back to FL350 and turn right to a heading of 010 degrees. The captain informed the controller that our previous clearance was to descend to FL290. The controller then told us that he had wanted us to turn to a heading of 290 degrees, not descend to FL290, and then instructed us to continue our turn to 030 degrees.

Original NASA ASRS Text

Title: ALTDEV ALT OVERSHOT IN DSCNT. CLRNC INTERP READBACK HEARBACK PROB.

Narrative: ZAU, ON FREQ 132.22, INSTRUCTED OUR ACFT TO DSND TO FL350, 'EXPEDITE THROUGH FL370' ON A HDG OF 330 DEGS FOR THE DSCNT. IN ORDER TO INCREASE OUR NORMAL RATE OF DSCNT, AS REQUESTED BY THE CTLR, I MANUALLY INTERVENED ON THE MCP IAS/MACH WINDOW TO INCREASE OUR NORMAL DSCNT SPD, THEREBY INCREASING THE ACFT'S RATE OF DSCNT. A SHORT TIME LATER, THE CTLR ASKED WHAT ALT WE WERE DSNDING THROUGH. THE CAPT REPLIED THAT WE WERE DSNDING THROUGH FL380. THE CTLR THEN IMMEDIATELY ISSUED A HDG CHANGE TO 290 DEGS. AT THIS TIME THE FREQ WAS VERY BUSY AND CONGESTED. THE CTLR WAS ISSUING NUMEROUS INSTRUCTIONS TO OUR ACFT AND OTHERS ON THE FREQ IN A VERY SHORT TIME PERIOD. THE CTLR THEN INSTRUCTED US TO, WHAT WE THOUGHT TO BE AT THAT TIME, A DSCNT TO FL290. THE CAPT ACKNOWLEDGED THE DSCNT ON THE RADIO AND I ENTERED 29000 INTO THE ALT WINDOW OF THE MCP. THE CAPT VERIFIED MY ENTRY AND ENTERED FL290 INTO THE CRZ ALT SPACE OF THE FMC CRZ PAGE. DSNDING THROUGH APPROX FL320 THE CTLR INSTRUCTED US TO CLB BACK TO FL350 AND TURN R TO A HDG OF 010 DEGS. THE CAPT INFORMED THE CTLR THAT OUR PREVIOUS CLRNC WAS TO DSND TO FL290. THE CTLR THEN TOLD US THAT HE HAD WANTED US TO TURN TO A HDG OF 290 DEGS, NOT DSND TO FL290, AND THEN INSTRUCTED US TO CONTINUE OUR TURN TO 030 DEGS.

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.