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Medium large transport missed new altitude assignment and ARTCC controller had less than standard separation between medium large transport and small transport.
| Attributes | |
| ACN | 89542 |
| Time | |
| Date | 198806 |
| Day | Tue |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | atc facility : gbn |
| State Reference | AZ |
| Altitude | msl bound lower : 28500 msl bound upper : 29000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Dusk |
| Aircraft 1 | |
| Controlling Facilities | artcc : zab |
| Operator | common carrier : air carrier |
| Make Model Name | Medium Large Transport, Low Wing, 2 Turbojet Eng |
| Flight Phase | climbout : intermediate altitude descent other |
| Route In Use | enroute airway : zab |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | general aviation : corporate |
| Make Model Name | Small Transport, Low Wing, 2 Turbojet Eng |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| Experience | controller non radar : 3 controller radar : 1 |
| ASRS Report | 89542 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | conflict : airborne less severe non adherence : required legal separation |
| Independent Detector | atc equipment other atc equipment : unspecified other controllera |
| Resolutory Action | controller : issued new clearance other |
| Consequence | Other |
| Miss Distance | horizontal : 25200 vertical : 500 |
| Supplementary | |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
An air carrier medium large transport X departed tus, headed nwbnd over gbn climbing to FL310. The second aircraft, a corporate small transport Y, headed southeast to gbn then tus. When both aircraft were about 30 apart and the air carrier was still climbing out of FL250, the controller told the air carrier to maintain FL280. The controller then heard a reply. When the traffic was at 10 mi the controller called traffic for both the medium large transport X and the small transport Y with the medium large transport X still climbing out of FL270 to FL280. The air carrier then questioned his altitude about 30 seconds later by saying he was assigned at FL310. The controller replied that he had been given a second clearance to FL280. The air carrier said that they hadn't received any clearance. The controller descended the air carrier 500' to FL280 and turned the small transport Y away from the medium large transport X. A few mins later another air carrier called and said he had checked on with center twice before and neither call was heard. The controller transmission was blocked by the second air carrier checking on. The controller didn't get a complete readback from the medium large transport X. The controller should get a complete readback from the aircraft which includes: call sign and clearance. If he/she doesn't get a complete readback, get on the aircraft for one. Also, due to a problem with frequency's clarity, the controller mistook the second air carrier's check on as the first air carrier readback. Had the frequencys been better the controller might have caught the error before it occurred. Callback conversation with reporter revealed the following: reporter gave experience level, only been fpl for approximately 6 months. Proximity of traffic was 4.2 NM and 500'. Reporter was working a combined position operation and not used to high altitude radio sounds.
Original NASA ASRS Text
Title: MLG MISSED NEW ALT ASSIGNMENT AND ARTCC CTLR HAD LESS THAN STANDARD SEPARATION BETWEEN MLG AND SMT.
Narrative: AN ACR MLG X DEPARTED TUS, HEADED NWBND OVER GBN CLBING TO FL310. THE SECOND ACFT, A CORPORATE SMT Y, HEADED SE TO GBN THEN TUS. WHEN BOTH ACFT WERE ABOUT 30 APART AND THE ACR WAS STILL CLBING OUT OF FL250, THE CTLR TOLD THE ACR TO MAINTAIN FL280. THE CTLR THEN HEARD A REPLY. WHEN THE TFC WAS AT 10 MI THE CTLR CALLED TFC FOR BOTH THE MLG X AND THE SMT Y WITH THE MLG X STILL CLBING OUT OF FL270 TO FL280. THE ACR THEN QUESTIONED HIS ALT ABOUT 30 SECS LATER BY SAYING HE WAS ASSIGNED AT FL310. THE CTLR REPLIED THAT HE HAD BEEN GIVEN A SECOND CLRNC TO FL280. THE ACR SAID THAT THEY HADN'T RECEIVED ANY CLRNC. THE CTLR DSNDED THE ACR 500' TO FL280 AND TURNED THE SMT Y AWAY FROM THE MLG X. A FEW MINS LATER ANOTHER ACR CALLED AND SAID HE HAD CHKED ON WITH CENTER TWICE BEFORE AND NEITHER CALL WAS HEARD. THE CTLR XMISSION WAS BLOCKED BY THE SECOND ACR CHKING ON. THE CTLR DIDN'T GET A COMPLETE READBACK FROM THE MLG X. THE CTLR SHOULD GET A COMPLETE READBACK FROM THE ACFT WHICH INCLUDES: CALL SIGN AND CLRNC. IF HE/SHE DOESN'T GET A COMPLETE READBACK, GET ON THE ACFT FOR ONE. ALSO, DUE TO A PROB WITH FREQ'S CLARITY, THE CTLR MISTOOK THE SECOND ACR'S CHK ON AS THE FIRST ACR READBACK. HAD THE FREQS BEEN BETTER THE CTLR MIGHT HAVE CAUGHT THE ERROR BEFORE IT OCCURRED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: RPTR GAVE EXPERIENCE LEVEL, ONLY BEEN FPL FOR APPROX 6 MONTHS. PROX OF TFC WAS 4.2 NM AND 500'. RPTR WAS WORKING A COMBINED POS OPERATION AND NOT USED TO HIGH ALT RADIO SOUNDS.
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.