Flight crew of a fokker FK10 responded to another similar sounding call sign clearance.

Attributes
ACN	441571
Time
Date	199906
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	navaid : ccv.vortac
State Reference	VA
Altitude	msl bound lower : 6000 msl bound upper : 9000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : orf.tracon
Operator	common carrier : air carrier
Make Model Name	Fokker 100
Operating Under FAR Part	Part 121
Navigation In Use	other other vortac
Flight Phase	descent : intermediate altitude
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tracon : orf.tracon
Operator	other
Make Model Name	Military
Operating Under FAR Part	Part 91
Flight Phase	descent : vacating altitude descent : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : atp pilot : multi engine pilot : instrument
Experience	flight time last 90 days : 200 flight time total : 11000 flight time type : 6000
ASRS Report	441571
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : multi engine pilot : instrument pilot : commercial
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other
Independent Detector	other controllera
Resolutory Action	controller : issued alert flight crew : returned to assigned airspace
Consequence	Other
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Our flight X was being controled by orf approach on VHF. Unbeknownst to us, a military flight with similar call sign, Y, was also being controled by orf approach on a local UHF circuit. Shortly after checking in with orf approach, we accepted a clearance to descend to 6000 ft MSL (from 9000 ft). All appropriate procedures, including use of our full call sign and 'altitude awareness' procedures were complied with by both crew members. The controller did not question our readback. After we acknowledged a call by the controller to expedite our descent, he informed us that his clrncs were intended for the heretofore unmentioned flight Y. We expeditiously returned to our previously assigned altitude. No conflict was created. I feel the strong possibility exists that the controller (mistakenly) did clear us to 6000 ft, only to realize his error after seeing flight Y not descend and asking flight Y to expedite descent. At this point he would have both seen flight X descending and heard us replying to his call to expedite the descent.

Original NASA ASRS Text

Title: FLC OF A FOKKER FK10 RESPONDED TO ANOTHER SIMILAR SOUNDING CALL SIGN CLRNC.

Narrative: OUR FLT X WAS BEING CTLED BY ORF APCH ON VHF. UNBEKNOWNST TO US, A MIL FLT WITH SIMILAR CALL SIGN, Y, WAS ALSO BEING CTLED BY ORF APCH ON A LCL UHF CIRCUIT. SHORTLY AFTER CHKING IN WITH ORF APCH, WE ACCEPTED A CLRNC TO DSND TO 6000 FT MSL (FROM 9000 FT). ALL APPROPRIATE PROCS, INCLUDING USE OF OUR FULL CALL SIGN AND 'ALT AWARENESS' PROCS WERE COMPLIED WITH BY BOTH CREW MEMBERS. THE CTLR DID NOT QUESTION OUR READBACK. AFTER WE ACKNOWLEDGED A CALL BY THE CTLR TO EXPEDITE OUR DSCNT, HE INFORMED US THAT HIS CLRNCS WERE INTENDED FOR THE HERETOFORE UNMENTIONED FLT Y. WE EXPEDITIOUSLY RETURNED TO OUR PREVIOUSLY ASSIGNED ALT. NO CONFLICT WAS CREATED. I FEEL THE STRONG POSSIBILITY EXISTS THAT THE CTLR (MISTAKENLY) DID CLR US TO 6000 FT, ONLY TO REALIZE HIS ERROR AFTER SEEING FLT Y NOT DSND AND ASKING FLT Y TO EXPEDITE DSCNT. AT THIS POINT HE WOULD HAVE BOTH SEEN FLT X DSNDING AND HEARD US REPLYING TO HIS CALL TO EXPEDITE THE DSCNT.

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.