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Flight crew of light transport took wrong clearance, ARTCC controller did not hearback, error was undetected until flight started descent.
| Attributes | |
| ACN | 119025 |
| Time | |
| Date | 198908 |
| Day | Tue |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | atc facility : mgw |
| State Reference | PA |
| Altitude | msl bound lower : 22000 msl bound upper : 23000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zob tower : oak |
| Operator | general aviation : corporate |
| Make Model Name | Light Transport, Low Wing, 2 Turbojet Eng |
| Flight Phase | cruise other descent other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | Other |
| Function | flight crew : first officer |
| Qualification | pilot : commercial pilot : instrument |
| ASRS Report | 119025 |
| Person 2 | |
| Affiliation | Other |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other |
| Independent Detector | other controllera |
| Resolutory Action | controller : issued new clearance other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
While en route, I had just completed the normal copilot duty of obtaining destination WX before our expected descent. Upon returning to center frequency, I heard center say, '...descend to and maintain 10000', altimeter 30.05.' I did not return to the frequency in time to hear the call sign. The captain started a descent and informed me that this clearance was for us. I replied, 'center, (our call sign) is out of FL230 for 1-1, 11 thousand, altimeter 30.05.' I received, 'roger.' passing FL221, center asked our altitude. I replied, '(our call sign) is passing FL221 for 1-1, 11 thousand.' we were told to return to FL230 and we complied. Approximately 30 seconds later we were cleared to descend and maintain 17000'. We acknowledged and complied. The captain asked if there was any conflict and center replied, 'no conflict.' we have many policies to prevent these types of occurrences. One policy is that if one crew member is unsure of a clearance, the clearance is to be confirmed before compliance. This is one of many normal situations when both pilots will not hear all xmissions before compliance. Another 30 seconds of receiving WX and I would not have been involved with the xmissions at all. Although I did not hear the complete transmission, I had not reasonable doubt that this transmission was for us since it was time for descent. The captain started the descent and was about acknowledge himself, and I read back our response and received an acknowledgement. Since I received this acknowledgement, I did not ask for further confirmation and did not feel it was necessary. Our policies already address and try to reduce as much as practical the time that both crew members are not backing each other up. These are normally limited to en route/cruise. In addition, the controllers must continue to improve their hearback techniques. They must hear what is being said, not what they are expecting to hear.
Original NASA ASRS Text
Title: FLT CREW OF LTT TOOK WRONG CLRNC, ARTCC CTLR DID NOT HEARBACK, ERROR WAS UNDETECTED UNTIL FLT STARTED DESCENT.
Narrative: WHILE ENRTE, I HAD JUST COMPLETED THE NORMAL COPLT DUTY OF OBTAINING DEST WX BEFORE OUR EXPECTED DSCNT. UPON RETURNING TO CENTER FREQ, I HEARD CENTER SAY, '...DSND TO AND MAINTAIN 10000', ALTIMETER 30.05.' I DID NOT RETURN TO THE FREQ IN TIME TO HEAR THE CALL SIGN. THE CAPT STARTED A DSCNT AND INFORMED ME THAT THIS CLRNC WAS FOR US. I REPLIED, 'CENTER, (OUR CALL SIGN) IS OUT OF FL230 FOR 1-1, 11 THOUSAND, ALTIMETER 30.05.' I RECEIVED, 'ROGER.' PASSING FL221, CENTER ASKED OUR ALT. I REPLIED, '(OUR CALL SIGN) IS PASSING FL221 FOR 1-1, 11 THOUSAND.' WE WERE TOLD TO RETURN TO FL230 AND WE COMPLIED. APPROX 30 SECS LATER WE WERE CLRED TO DSND AND MAINTAIN 17000'. WE ACKNOWLEDGED AND COMPLIED. THE CAPT ASKED IF THERE WAS ANY CONFLICT AND CENTER REPLIED, 'NO CONFLICT.' WE HAVE MANY POLICIES TO PREVENT THESE TYPES OF OCCURRENCES. ONE POLICY IS THAT IF ONE CREW MEMBER IS UNSURE OF A CLRNC, THE CLRNC IS TO BE CONFIRMED BEFORE COMPLIANCE. THIS IS ONE OF MANY NORMAL SITUATIONS WHEN BOTH PLTS WILL NOT HEAR ALL XMISSIONS BEFORE COMPLIANCE. ANOTHER 30 SECS OF RECEIVING WX AND I WOULD NOT HAVE BEEN INVOLVED WITH THE XMISSIONS AT ALL. ALTHOUGH I DID NOT HEAR THE COMPLETE XMISSION, I HAD NOT REASONABLE DOUBT THAT THIS XMISSION WAS FOR US SINCE IT WAS TIME FOR DSCNT. THE CAPT STARTED THE DSCNT AND WAS ABOUT ACKNOWLEDGE HIMSELF, AND I READ BACK OUR RESPONSE AND RECEIVED AN ACKNOWLEDGEMENT. SINCE I RECEIVED THIS ACKNOWLEDGEMENT, I DID NOT ASK FOR FURTHER CONFIRMATION AND DID NOT FEEL IT WAS NECESSARY. OUR POLICIES ALREADY ADDRESS AND TRY TO REDUCE AS MUCH AS PRACTICAL THE TIME THAT BOTH CREW MEMBERS ARE NOT BACKING EACH OTHER UP. THESE ARE NORMALLY LIMITED TO ENRTE/CRUISE. IN ADDITION, THE CTLRS MUST CONTINUE TO IMPROVE THEIR HEARBACK TECHNIQUES. THEY MUST HEAR WHAT IS BEING SAID, NOT WHAT THEY ARE EXPECTING TO HEAR.
Data retrieved from NASA's ASRS site as of August 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.