Air carrier X responded to wrong call sign. Non adherence to ATC clearance. Altitude deviation.

Attributes
ACN	293770
Time
Date	199501
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : gdm
State Reference	MA
Altitude	msl bound lower : 18000 msl bound upper : 18000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zbw tracon : grk
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	cruise other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 11000 flight time type : 2500
ASRS Report	293770
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Experience	flight time last 90 days : 170 flight time total : 8500 flight time type : 3300
ASRS Report	293772
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance other spatial deviation
Independent Detector	other flight crewa
Resolutory Action	controller : issued new clearance other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Air carrier X going to hold at gdm when we received a heading of 310 degrees and an altitude of FL180. At the time we were descending through FL200, we thought we received a clearance of direct to gdm and descend to 11000 ft. The first officer read the clearance back. As we were going through FL180 and turning through 290 degrees, the controller said '310 degrees on gdm heading.' we rolled back to a 290 degree heading and stopped the descent at 17600 ft and went to FL180. We asked the controller about the clearance and he said it was for a flight. We asked if he had heard our readback and he said 2 aircraft blocked each other. Supplemental information from acn 293772: I then understood a clearance of 'fly left direct to gdm, cross bronc at and maintain 11000 ft at 210 KTS. At the time we were at FL200. I repeated the entire clearance, including our call sign -- air carrier X. Another flight called center and said another flight had taken his clearance. Center called us and told us to fly the 310 degree radial and maintain FL180.

Original NASA ASRS Text

Title: ACR X RESPONDED TO WRONG CALL SIGN. NON ADHERENCE TO ATC CLRNC. ALTDEV.

Narrative: ACR X GOING TO HOLD AT GDM WHEN WE RECEIVED A HDG OF 310 DEGS AND AN ALT OF FL180. AT THE TIME WE WERE DSNDING THROUGH FL200, WE THOUGHT WE RECEIVED A CLRNC OF DIRECT TO GDM AND DSND TO 11000 FT. THE FO READ THE CLRNC BACK. AS WE WERE GOING THROUGH FL180 AND TURNING THROUGH 290 DEGS, THE CTLR SAID '310 DEGS ON GDM HDG.' WE ROLLED BACK TO A 290 DEG HDG AND STOPPED THE DSCNT AT 17600 FT AND WENT TO FL180. WE ASKED THE CTLR ABOUT THE CLRNC AND HE SAID IT WAS FOR A FLT. WE ASKED IF HE HAD HEARD OUR READBACK AND HE SAID 2 ACFT BLOCKED EACH OTHER. SUPPLEMENTAL INFO FROM ACN 293772: I THEN UNDERSTOOD A CLRNC OF 'FLY L DIRECT TO GDM, CROSS BRONC AT AND MAINTAIN 11000 FT AT 210 KTS. AT THE TIME WE WERE AT FL200. I REPEATED THE ENTIRE CLRNC, INCLUDING OUR CALL SIGN -- ACR X. ANOTHER FLT CALLED CTR AND SAID ANOTHER FLT HAD TAKEN HIS CLRNC. CTR CALLED US AND TOLD US TO FLY THE 310 DEG RADIAL AND MAINTAIN FL180.

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.