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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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ARTCC radar controller in training cleared a LR25 to descend to FL310 and turn to a 270 degree heading. Aircraft read back correct heading, but said descend to FL270. Trainee controller reclred aircraft direct tlh and descend to FL310, but the aircraft descended through FL310 far enough to lose separation with an air carrier CL60 at FL290.
| Attributes | |
| ACN | 349820 |
| Time | |
| Date | 199610 |
| Day | Tue |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | atc facility : pie |
| State Reference | FL |
| Altitude | msl bound lower : 30500 msl bound upper : 31000 |
| Environment | |
| Flight Conditions | Mixed |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zjx |
| Operator | general aviation : personal |
| Make Model Name | Learjet 25 |
| Operating Under FAR Part | Part 91 |
| Flight Phase | descent other |
| Route In Use | enroute : on vectors |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | common carrier : air carrier |
| Make Model Name | Medium Transport, Low Wing, 2 Turbojet Eng |
| Navigation In Use | Other |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : flight data |
| Qualification | controller : radar |
| Experience | controller military : 4 controller radar : 16 |
| ASRS Report | 349820 |
| Person 2 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : developmental |
| Events | |
| Anomaly | altitude deviation : overshoot conflict : airborne less severe non adherence : clearance non adherence : required legal separation |
| Independent Detector | atc equipment other atc equipment : unspecified |
| Resolutory Action | controller : issued new clearance |
| Consequence | Other |
| Miss Distance | horizontal : 30000 vertical : 1500 |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
CL60 aircraft sbound at FL290. LR25 aircraft northbound at FL390. LR25 aircraft landing tlh so descent clearance issued to FL310 along with a turn to 270 degrees. LR25 read back heading 270 degrees and also descending to FL270. Right side (training) reclred aircraft direct tlh and descent to FL310. This time LR25 read back the clearance correctly, direct tlh and descending to FL310. Conflict alert activated as LR25 descends through FL310 and right side told the LR25 about the sbound CL60 at FL290. LR25 reported level at FL310 just before separation was lost. I think the LR25 didn't realize that he had been given a new altitude, even though the LR25 read back the revised altitude. There was controller training on the right side. The right side instructor caught the first readback error, but the trainee didn't. I was working the d-side and didn't hear the missed readback either. Instructor took no immediate action to correct the wrong readback by the LR25 pilot, because the trainee just a few seconds later reclred the aircraft direct tlh and reissued descent to FL310. LR25 did read back this clearance correctly.
Original NASA ASRS Text
Title: ARTCC RADAR CTLR IN TRAINING CLRED A LR25 TO DSND TO FL310 AND TURN TO A 270 DEG HDG. ACFT READ BACK CORRECT HDG, BUT SAID DSND TO FL270. TRAINEE CTLR RECLRED ACFT DIRECT TLH AND DSND TO FL310, BUT THE ACFT DSNDED THROUGH FL310 FAR ENOUGH TO LOSE SEPARATION WITH AN ACR CL60 AT FL290.
Narrative: CL60 ACFT SBOUND AT FL290. LR25 ACFT NBOUND AT FL390. LR25 ACFT LNDG TLH SO DSCNT CLRNC ISSUED TO FL310 ALONG WITH A TURN TO 270 DEGS. LR25 READ BACK HDG 270 DEGS AND ALSO DSNDING TO FL270. R SIDE (TRAINING) RECLRED ACFT DIRECT TLH AND DSCNT TO FL310. THIS TIME LR25 READ BACK THE CLRNC CORRECTLY, DIRECT TLH AND DSNDING TO FL310. CONFLICT ALERT ACTIVATED AS LR25 DSNDS THROUGH FL310 AND R SIDE TOLD THE LR25 ABOUT THE SBOUND CL60 AT FL290. LR25 RPTED LEVEL AT FL310 JUST BEFORE SEPARATION WAS LOST. I THINK THE LR25 DIDN'T REALIZE THAT HE HAD BEEN GIVEN A NEW ALT, EVEN THOUGH THE LR25 READ BACK THE REVISED ALT. THERE WAS CTLR TRAINING ON THE R SIDE. THE R SIDE INSTRUCTOR CAUGHT THE FIRST READBACK ERROR, BUT THE TRAINEE DIDN'T. I WAS WORKING THE D-SIDE AND DIDN'T HEAR THE MISSED READBACK EITHER. INSTRUCTOR TOOK NO IMMEDIATE ACTION TO CORRECT THE WRONG READBACK BY THE LR25 PLT, BECAUSE THE TRAINEE JUST A FEW SECONDS LATER RECLRED THE ACFT DIRECT TLH AND REISSUED DSCNT TO FL310. LR25 DID READ BACK THIS CLRNC CORRECTLY.
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.