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Similar sounding flight numbers and a heavily accented departure controller's voice contribute flight crew accepting and executing a clearance intended for another aircraft.
| Attributes | |
| ACN | 794448 |
| Time | |
| Date | 200807 |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | airport : egll.airport |
| State Reference | FO |
| Altitude | msl bound lower : 6000 msl bound upper : 14000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tracon : egtt.tracon |
| Operator | common carrier : air carrier |
| Make Model Name | Widebody Low Wing 2 Turbojet Eng |
| Operating Under FAR Part | Part 121 |
| Flight Phase | climbout : initial |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | tracon : egtt.tracon |
| Operator | common carrier : air carrier |
| Make Model Name | Commercial Fixed Wing |
| Operating Under FAR Part | Part 121 |
| Flight Phase | climbout : initial |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 250 flight time total : 14000 flight time type : 3000 |
| ASRS Report | 794448 |
| Person 2 | |
| Affiliation | company : air carrier |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other other spatial deviation |
| Independent Detector | other flight crewa |
| Resolutory Action | controller : issued new clearance controller : issued alert flight crew : returned to intended or assigned course |
| Supplementary | |
| Problem Areas | Flight Crew Human Performance ATC Human Performance |
| Primary Problem | ATC Human Performance |
Narrative:
After takeoff; we were assigned heading 025 degrees; 6000 ft. On that vector we picked up a clearance to turn to 335 degrees and climb to FL140. We verified the clearance and our readback was confirmed 3 times by ATC. While in the turn and climb; we heard another aircraft (similar call sign) tell ATC that we were picking up 'their' clearance to turn to 335 degrees and climb to FL140. At that point; ATC advised us to return to 025 degrees and 'stop' our climb at FL090. We again confirmed 'our' clearance and complied. ATC again verified our readback. No conflict with other aircraft. The problem here is that ATC referred to us as aircraft nine nine and also aircraft 'ninety nine;' which has a similar ring to 'nine twenty nine' when said in her voice. We purposely used 'niner;' as per ICAO guidelines to ensure clarity of our call sign and 'articulated' communications. With ATC 'not' using ICAO communications phraseology; that caused a huge confusion factor for us and other aircraft; as well as 'creating' a very awkward situation in 'enducing' a flight deviation of altitude and heading in a very busy network and environment around lhr; all of which could have been avoided if she had articulated properly.
Original NASA ASRS Text
Title: SIMILAR SOUNDING FLT NUMBERS AND A HEAVILY ACCENTED DEP CONTROLLER'S VOICE CONTRIBUTE FLT CREW ACCEPTING AND EXECUTING A CLRNC INTENDED FOR ANOTHER ACFT.
Narrative: AFTER TKOF; WE WERE ASSIGNED HDG 025 DEGS; 6000 FT. ON THAT VECTOR WE PICKED UP A CLRNC TO TURN TO 335 DEGS AND CLB TO FL140. WE VERIFIED THE CLRNC AND OUR READBACK WAS CONFIRMED 3 TIMES BY ATC. WHILE IN THE TURN AND CLB; WE HEARD ANOTHER ACFT (SIMILAR CALL SIGN) TELL ATC THAT WE WERE PICKING UP 'THEIR' CLRNC TO TURN TO 335 DEGS AND CLB TO FL140. AT THAT POINT; ATC ADVISED US TO RETURN TO 025 DEGS AND 'STOP' OUR CLB AT FL090. WE AGAIN CONFIRMED 'OUR' CLRNC AND COMPLIED. ATC AGAIN VERIFIED OUR READBACK. NO CONFLICT WITH OTHER ACFT. THE PROB HERE IS THAT ATC REFERRED TO US AS ACFT NINE NINE AND ALSO ACFT 'NINETY NINE;' WHICH HAS A SIMILAR RING TO 'NINE TWENTY NINE' WHEN SAID IN HER VOICE. WE PURPOSELY USED 'NINER;' AS PER ICAO GUIDELINES TO ENSURE CLARITY OF OUR CALL SIGN AND 'ARTICULATED' COMS. WITH ATC 'NOT' USING ICAO COMS PHRASEOLOGY; THAT CAUSED A HUGE CONFUSION FACTOR FOR US AND OTHER ACFT; AS WELL AS 'CREATING' A VERY AWKWARD SITUATION IN 'ENDUCING' A FLT DEV OF ALT AND HDG IN A VERY BUSY NETWORK AND ENVIRONMENT AROUND LHR; ALL OF WHICH COULD HAVE BEEN AVOIDED IF SHE HAD ARTICULATED PROPERLY.
Data retrieved from NASA's ASRS site as of May 2009 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.