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Apparent situation in which the flight crew of an air carrier L1011 missed the initial call by the controller to descend from FL330 to FL270 and required a subsequent call for a 30 degree turn and descent clearance to FL270 to avoid traffic at FL330.
| Attributes | |
| ACN | 399220 |
| Time | |
| Date | 199804 |
| Day | Fri |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : tlh |
| State Reference | FL |
| Altitude | msl bound lower : 33000 msl bound upper : 33000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zjx tower : dfw |
| Operator | common carrier : air carrier |
| Make Model Name | L-1011-500 Series |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Aircraft 2 | |
| Make Model Name | Any Unknown or Unlisted Aircraft Manufacturer |
| Operating Under FAR Part | other : unknown |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | other other : other pilot : commercial pilot : flight engineer pilot : instrument pilot : atp |
| Experience | flight time last 90 days : 160 flight time total : 20000 flight time type : 1900 |
| ASRS Report | 399220 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | other other : other pilot : instrument pilot : flight engineer pilot : commercial pilot : atp |
| Experience | flight time last 90 days : 150 flight time total : 6000 flight time type : 1000 |
| ASRS Report | 399668 |
| Events | |
| Anomaly | conflict : airborne less severe other anomaly other |
| Independent Detector | other controllera |
| Resolutory Action | controller : issued new clearance other |
| Consequence | Other |
| Miss Distance | horizontal : 48000 vertical : 1500 |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | other |
Narrative:
On cruise at FL330 we heard a call for our flight to expedite descent to FL270. As we were about to verify that we were cleared to descend, the controller issued another clearance to turn right 30 degrees immediately and descend immediately to FL270. We observed an aircraft on TCASII at FL330 at 11 O'clock and closing. We complied and observed the aircraft on TCASII close to about 8 NM. Evidently the controller had issued a descent clearance to us previously that we had not received or responded to and it was not followed up. Callback conversation with reporter revealed the following information: reporter is not aware of a loss of separation although reporter heard the controller issue a turn clearance to the other aircraft. Reporter stated that they did not visually see the other aircraft or know its category and type. Reporter indicated he did not make a follow up call to the facility about the incident.
Original NASA ASRS Text
Title: APPARENT SIT IN WHICH THE FLC OF AN ACR L1011 MISSED THE INITIAL CALL BY THE CTLR TO DSND FROM FL330 TO FL270 AND REQUIRED A SUBSEQUENT CALL FOR A 30 DEG TURN AND DSCNT CLRNC TO FL270 TO AVOID TFC AT FL330.
Narrative: ON CRUISE AT FL330 WE HEARD A CALL FOR OUR FLT TO EXPEDITE DSCNT TO FL270. AS WE WERE ABOUT TO VERIFY THAT WE WERE CLRED TO DSND, THE CTLR ISSUED ANOTHER CLRNC TO TURN R 30 DEGS IMMEDIATELY AND DSND IMMEDIATELY TO FL270. WE OBSERVED AN ACFT ON TCASII AT FL330 AT 11 O'CLOCK AND CLOSING. WE COMPLIED AND OBSERVED THE ACFT ON TCASII CLOSE TO ABOUT 8 NM. EVIDENTLY THE CTLR HAD ISSUED A DSCNT CLRNC TO US PREVIOUSLY THAT WE HAD NOT RECEIVED OR RESPONDED TO AND IT WAS NOT FOLLOWED UP. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR IS NOT AWARE OF A LOSS OF SEPARATION ALTHOUGH RPTR HEARD THE CTLR ISSUE A TURN CLRNC TO THE OTHER ACFT. RPTR STATED THAT THEY DID NOT VISUALLY SEE THE OTHER ACFT OR KNOW ITS CATEGORY AND TYPE. RPTR INDICATED HE DID NOT MAKE A FOLLOW UP CALL TO THE FACILITY ABOUT THE INCIDENT.
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.