Air carrier medium large transport altitude deviation overshot during descent.

Attributes
ACN	108757
Time
Date	198904
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : bpr
State Reference	TX
Altitude	msl bound lower : 11000 msl bound upper : 12000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : dfw
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other descent other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : instrument pilot : cfi pilot : commercial pilot : flight engineer
Experience	flight time last 90 days : 210 flight time total : 9000 flight time type : 250
ASRS Report	108757
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	altitude deviation : overshoot other anomaly other
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	Other
Supplementary
Primary Problem	Ambiguous
Air Traffic Incident	Operational Deviation Pilot Deviation

Narrative:

Received clearance from high controller to cross pivit intersection at 11000' which is normal procedure. Subsequent controller was contacted and advised that aircraft was descending to 11000'. Controller's response was blocked, then we heard, 'reduce to 250 K,' which I read back. Controller was very busy. After 2 mins controller requested our altitude. We responded 11000' level. Controller said we were supposed to be at 12000'. We responded that we were cleared to 11000'. The rest of the approach was normal. No conflict was advised and nothing further was said. At this time no word has come from the FAA. I feel that the controller may have issued a restriction to level at 12000' which was blocked. I did not hear nor acknowledge a 12000' restriction. The controller was so busy that he did not have time to hearback a clearance and may have assumed that we heard 12000'. In the future I plan to make sure controllers understand that a clearance has been blocked that may have been intended for me.

Original NASA ASRS Text

Title: ACR MLG ALT DEVIATION OVERSHOT DURING DESCENT.

Narrative: RECEIVED CLRNC FROM HIGH CTLR TO CROSS PIVIT INTXN AT 11000' WHICH IS NORMAL PROC. SUBSEQUENT CTLR WAS CONTACTED AND ADVISED THAT ACFT WAS DSNDING TO 11000'. CTLR'S RESPONSE WAS BLOCKED, THEN WE HEARD, 'REDUCE TO 250 K,' WHICH I READ BACK. CTLR WAS VERY BUSY. AFTER 2 MINS CTLR REQUESTED OUR ALT. WE RESPONDED 11000' LEVEL. CTLR SAID WE WERE SUPPOSED TO BE AT 12000'. WE RESPONDED THAT WE WERE CLRED TO 11000'. THE REST OF THE APCH WAS NORMAL. NO CONFLICT WAS ADVISED AND NOTHING FURTHER WAS SAID. AT THIS TIME NO WORD HAS COME FROM THE FAA. I FEEL THAT THE CTLR MAY HAVE ISSUED A RESTRICTION TO LEVEL AT 12000' WHICH WAS BLOCKED. I DID NOT HEAR NOR ACKNOWLEDGE A 12000' RESTRICTION. THE CTLR WAS SO BUSY THAT HE DID NOT HAVE TIME TO HEARBACK A CLRNC AND MAY HAVE ASSUMED THAT WE HEARD 12000'. IN THE FUTURE I PLAN TO MAKE SURE CTLRS UNDERSTAND THAT A CLRNC HAS BEEN BLOCKED THAT MAY HAVE BEEN INTENDED FOR ME.

Data retrieved from NASA's ASRS site as of August 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.