Air carrier X descent to wrong altitude. Pilot deviation.

Attributes
ACN	218487
Time
Date	199208
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : pvd
State Reference	RI
Altitude	msl bound lower : 10000 msl bound upper : 11000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	enroute : direct enroute airway : zbw
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 20000 flight time type : 3000
ASRS Report	218487
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	altitude deviation : overshoot non adherence : clearance other anomaly other
Independent Detector	other controllera
Resolutory Action	flight crew : returned to intended course or assigned course other
Consequence	faa : investigated faa : reviewed incident with flight crew
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

The clearance I remember, and the clearance my first officer responded to, was 'air carrier X cleared direct providence, victor 151 to boston, maintain 10000 ft.' the first officer was flying and programmed the mode control panel for altitude (10000 ft) while I was inserting the route into the FMS. At 10500 ft or so, the center controller requested that we maintain 11000 ft. I replied that I thought we were cleared to 10000, but that we were returning to 11000. The controller, without further comment, turned us over to approach control, and we checked on at 11000. After landing boston, a telephone call to approach control confirmed that the center controller was as sure about issuing 11000 as we were about receiving 10000. Our communication system is probably our weakest link. Boston was IMC, traffic was backed up all the way to several stacked holding patterns around the area. Under those conditions the load on the flight crew is heavy while the task of the controller sounds almost impossible. Everyone does their best, but the number of misidentifies, partially blocked clrncs and replies, the transpositions, required repeats, and undetected errors in readbacks can and often does approach the level of chaos.

Original NASA ASRS Text

Title: ACR X DSCNT TO WRONG ALT. PLTDEV.

Narrative: THE CLRNC I REMEMBER, AND THE CLRNC MY FO RESPONDED TO, WAS 'ACR X CLRED DIRECT PROVIDENCE, VICTOR 151 TO BOSTON, MAINTAIN 10000 FT.' THE FO WAS FLYING AND PROGRAMMED THE MODE CTL PANEL FOR ALT (10000 FT) WHILE I WAS INSERTING THE RTE INTO THE FMS. AT 10500 FT OR SO, THE CTR CTLR REQUESTED THAT WE MAINTAIN 11000 FT. I REPLIED THAT I THOUGHT WE WERE CLRED TO 10000, BUT THAT WE WERE RETURNING TO 11000. THE CTLR, WITHOUT FURTHER COMMENT, TURNED US OVER TO APCH CTL, AND WE CHKED ON AT 11000. AFTER LNDG BOSTON, A TELEPHONE CALL TO APCH CTL CONFIRMED THAT THE CTR CTLR WAS AS SURE ABOUT ISSUING 11000 AS WE WERE ABOUT RECEIVING 10000. OUR COM SYS IS PROBABLY OUR WEAKEST LINK. BOSTON WAS IMC, TFC WAS BACKED UP ALL THE WAY TO SEVERAL STACKED HOLDING PATTERNS AROUND THE AREA. UNDER THOSE CONDITIONS THE LOAD ON THE FLC IS HVY WHILE THE TASK OF THE CTLR SOUNDS ALMOST IMPOSSIBLE. EVERYONE DOES THEIR BEST, BUT THE NUMBER OF MISIDENTS, PARTIALLY BLOCKED CLRNCS AND REPLIES, THE TRANSPOSITIONS, REQUIRED REPEATS, AND UNDETECTED ERRORS IN READBACKS CAN AND OFTEN DOES APCH THE LEVEL OF CHAOS.

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.