Air carrier large transport altitude deviation excursion from clearance altitude in response to wron...

Attributes
ACN	146694
Time
Date	199005
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : ilm
State Reference	NC
Altitude	msl bound lower : 12600 msl bound upper : 13000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	cruise other
Route In Use	enroute airway : zjx
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : second officer
Qualification	pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 160 flight time total : 3500
ASRS Report	146694
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : cfi pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 200 flight time total : 9000
ASRS Report	146696
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance
Independent Detector	other flight crewa
Resolutory Action	controller : issued new clearance flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Ambiguous
Air Traffic Incident	Operational Deviation Pilot Deviation other

Narrative:

While cruising at 13000' on a flight from myr to rdu, ZJX cleared our flight (company acaf) to descend to 12000'. The first officer read back the clearance and the captain initiated descent to 12000'. Approximately 20-30 seconds later jax clearance cleared company acfh to descend to 12000' and they acknowledged their clearance. Because of the similarity of the callsigns our first officer asked ZJX to confirm our clearance to descend to 12000'. At this time jax clearance directed us to maintain 13000'. Our altitude by this time was 12600'. We stopped our descent immediately and returned to 13000'. It is my opinion that ZJX incorrectly cleared us to 12000', and then realized his mistake and reissued clearance for company acfh. Regardless of whose error this was, the problem could probably have been averted if ZJX had advised us that another company flight with a similar callsign was also on frequency.

Original NASA ASRS Text

Title: ACR LGT ALT DEVIATION EXCURSION FROM CLRNC ALT IN RESPONSE TO WRONG CALLSIGN.

Narrative: WHILE CRUISING AT 13000' ON A FLT FROM MYR TO RDU, ZJX CLRED OUR FLT (COMPANY ACAF) TO DSND TO 12000'. THE F/O READ BACK THE CLRNC AND THE CAPT INITIATED DSNT TO 12000'. APPROX 20-30 SECS LATER JAX CLRNC CLRED COMPANY ACFH TO DSND TO 12000' AND THEY ACKNOWLEDGED THEIR CLRNC. BECAUSE OF THE SIMILARITY OF THE CALLSIGNS OUR F/O ASKED ZJX TO CONFIRM OUR CLRNC TO DSND TO 12000'. AT THIS TIME JAX CLRNC DIRECTED US TO MAINTAIN 13000'. OUR ALT BY THIS TIME WAS 12600'. WE STOPPED OUR DSNT IMMEDIATELY AND RETURNED TO 13000'. IT IS MY OPINION THAT ZJX INCORRECTLY CLRED US TO 12000', AND THEN REALIZED HIS MISTAKE AND REISSUED CLRNC FOR COMPANY ACFH. REGARDLESS OF WHOSE ERROR THIS WAS, THE PROB COULD PROBABLY HAVE BEEN AVERTED IF ZJX HAD ADVISED US THAT ANOTHER COMPANY FLT WITH A SIMILAR CALLSIGN WAS ALSO ON FREQ.

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.

Air carrier large transport altitude deviation excursion from clearance altitude in response to wrong callsign.