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An A320 flight crew leaves their assigned altitude when they copy a clearance meant for another air carrier flight with a similar sounding call sign on frequency with ZAB, NM.
| Attributes | |
| ACN | 452038 |
| Time | |
| Date | 199910 |
| Day | Fri |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| State Reference | NM |
| Altitude | msl bound lower : 34650 msl bound upper : 35000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zab.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | A320 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other |
| Flight Phase | cruise : level cruise : enroute altitude change |
| Route In Use | arrival star : fossl 4 |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | artcc : zab.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | B737-300 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | cruise : level |
| Route In Use | arrival star : fossl 4 |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 250 flight time total : 14000 flight time type : 800 |
| ASRS Report | 452038 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : instrument pilot : multi engine pilot : commercial |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude non adherence : clearance |
| Independent Detector | other controllera |
| Resolutory Action | controller : issued advisory |
| Consequence | faa : reviewed incident with flight crew |
| Supplementary | |
| Problem Areas | Flight Crew Human Performance Environmental Factor ATC Human Performance |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
On oct/xa/99 at about XA30, we (an airbus A320) were about 20 mi east of sacho intersection on the fossl arrival into phx at FL350. ZAB issued a crossing restr to us to cross sacho at FL310. The first officer acknowledged the clearance and I, as the PF, set FL310 in the altitude window. As we were only 20 mi from the fix, I decided to start down at that time to give the passenger a smooth descent and leveloff. The first officer called ZAB to tell them we were leaving FL350. The controller told us to maintain FL350, that he had not given us a clearance to descend, but that he had issued the restr to air carrier, aff (as we were being called cff) (the first number is dropped for ATC communications.) the call signs were similar. During this exchange, I disconnected the autoplt and immediately stopped the descent and returned to FL350. We had descended about 350 ft to about FL346.5 before returning to FL350. The first officer advised ZAB of our readback and the controller retorted that our readback wasn't important (words to that affect), but it was our responsibility to 'listen up.' I believe his attitude is a result of the recent FAA ruling saying controllers are not responsible to catch erroneous readbacks, but pilots are responsible to correctly hear and interpretation ATC clrncs.
Original NASA ASRS Text
Title: AN A320 FLC LEAVES THEIR ASSIGNED ALT WHEN THEY COPY A CLRNC MEANT FOR ANOTHER ACR FLT WITH A SIMILAR SOUNDING CALL SIGN ON FREQ WITH ZAB, NM.
Narrative: ON OCT/XA/99 AT ABOUT XA30, WE (AN AIRBUS A320) WERE ABOUT 20 MI E OF SACHO INTXN ON THE FOSSL ARR INTO PHX AT FL350. ZAB ISSUED A XING RESTR TO US TO CROSS SACHO AT FL310. THE FO ACKNOWLEDGED THE CLRNC AND I, AS THE PF, SET FL310 IN THE ALT WINDOW. AS WE WERE ONLY 20 MI FROM THE FIX, I DECIDED TO START DOWN AT THAT TIME TO GIVE THE PAX A SMOOTH DSCNT AND LEVELOFF. THE FO CALLED ZAB TO TELL THEM WE WERE LEAVING FL350. THE CTLR TOLD US TO MAINTAIN FL350, THAT HE HAD NOT GIVEN US A CLRNC TO DSND, BUT THAT HE HAD ISSUED THE RESTR TO ACR, AFF (AS WE WERE BEING CALLED CFF) (THE FIRST NUMBER IS DROPPED FOR ATC COMS.) THE CALL SIGNS WERE SIMILAR. DURING THIS EXCHANGE, I DISCONNECTED THE AUTOPLT AND IMMEDIATELY STOPPED THE DSCNT AND RETURNED TO FL350. WE HAD DSNDED ABOUT 350 FT TO ABOUT FL346.5 BEFORE RETURNING TO FL350. THE FO ADVISED ZAB OF OUR READBACK AND THE CTLR RETORTED THAT OUR READBACK WASN'T IMPORTANT (WORDS TO THAT AFFECT), BUT IT WAS OUR RESPONSIBILITY TO 'LISTEN UP.' I BELIEVE HIS ATTITUDE IS A RESULT OF THE RECENT FAA RULING SAYING CTLRS ARE NOT RESPONSIBLE TO CATCH ERRONEOUS READBACKS, BUT PLTS ARE RESPONSIBLE TO CORRECTLY HEAR AND INTERP ATC CLRNCS.
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.