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An A320 flight crew accepts a lower altitude clearance for another flight with a similar sounding call sign, descends to occupied altitude and is further cleared lower to avoid opposite direction traffic 40 mi north of sav, GA.
| Attributes | |
| ACN | 478694 |
| Time | |
| Date | 200007 |
| Day | Wed |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | airport : sav.airport |
| State Reference | GA |
| Altitude | msl bound lower : 25000 msl bound upper : 27000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zjx.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | A320 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other vortac |
| Flight Phase | cruise : enroute altitude change |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | artcc : zjx.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | Commercial Fixed Wing |
| Operating Under FAR Part | Part 121 |
| Flight Phase | cruise : enroute altitude change |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 190 flight time total : 18000 flight time type : 1100 |
| ASRS Report | 478694 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : multi engine pilot : commercial pilot : instrument |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : clearance other anomaly other |
| Independent Detector | aircraft equipment : tcas other controllera |
| Resolutory Action | controller : issued new clearance controller : separated traffic controller : issued alert flight crew : took precautionary avoidance action |
| Consequence | Other |
| Miss Distance | horizontal : 78000 vertical : 1000 |
| Supplementary | |
| Problem Areas | Flight Crew Human Performance Environmental Factor Airspace Structure ATC Human Performance |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
We were issued a descent to FL250, which we read back. Reaching FL250, ATC said 'air carrier Y, air carrier Y, you are supposed to be at FL270. I see you are almost at FL250, descend to FL240 -- good rate.' we complied. Just as we leveled at FL240, we got a TCASII TA of an aircraft at our 1 O'clock position and 800 ft above us. TCASII TA almost immediately ceased as we leveled. Nothing further was said by ATC. My first officer and I think that we heard ATC correctly. We read back the clearance, with no subsequent correction by ATC. We noted there was a similar call sign on our frequency (air carrier Y abb). ATC did not advise us of this, but we did hear him earlier. The ATC quote on the previous page may be paraphrased. Incidents like this occur because of the frailty of verbal communication which we are forced to depend upon. ATC and pilots need data link now!
Original NASA ASRS Text
Title: AN A320 FLC ACCEPTS A LOWER ALT CLRNC FOR ANOTHER FLT WITH A SIMILAR SOUNDING CALL SIGN, DSNDS TO OCCUPIED ALT AND IS FURTHER CLRED LOWER TO AVOID OPPOSITE DIRECTION TFC 40 MI N OF SAV, GA.
Narrative: WE WERE ISSUED A DSCNT TO FL250, WHICH WE READ BACK. REACHING FL250, ATC SAID 'ACR Y, ACR Y, YOU ARE SUPPOSED TO BE AT FL270. I SEE YOU ARE ALMOST AT FL250, DSND TO FL240 -- GOOD RATE.' WE COMPLIED. JUST AS WE LEVELED AT FL240, WE GOT A TCASII TA OF AN ACFT AT OUR 1 O'CLOCK POS AND 800 FT ABOVE US. TCASII TA ALMOST IMMEDIATELY CEASED AS WE LEVELED. NOTHING FURTHER WAS SAID BY ATC. MY FO AND I THINK THAT WE HEARD ATC CORRECTLY. WE READ BACK THE CLRNC, WITH NO SUBSEQUENT CORRECTION BY ATC. WE NOTED THERE WAS A SIMILAR CALL SIGN ON OUR FREQ (ACR Y ABB). ATC DID NOT ADVISE US OF THIS, BUT WE DID HEAR HIM EARLIER. THE ATC QUOTE ON THE PREVIOUS PAGE MAY BE PARAPHRASED. INCIDENTS LIKE THIS OCCUR BECAUSE OF THE FRAILTY OF VERBAL COM WHICH WE ARE FORCED TO DEPEND UPON. ATC AND PLTS NEED DATA LINK NOW!
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.