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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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ARTCC radar controller descended a B757 to same altitude as traffic below him, a B737. Controller put correct altitude of FL350 in data block, but spoke the wrong altitude (FL330) which was the B737's altitude. B757 flight crew had B737 in sight both visually and on TCASII and when controller asked what altitude they were descending to, had them stop at current altitude until clear of the traffic.
| Attributes | |
| ACN | 342615 |
| Time | |
| Date | 199607 |
| Day | Sun |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : pxt |
| State Reference | MD |
| Altitude | msl bound lower : 33000 msl bound upper : 34300 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zdc |
| Operator | common carrier : air carrier |
| Make Model Name | B757 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other Other |
| Flight Phase | descent other |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | common carrier : air carrier |
| Make Model Name | B737 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| Experience | controller radar : 10 |
| ASRS Report | 342615 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : instrument pilot : commercial pilot : atp |
| Experience | flight time last 90 days : 180 flight time total : 8000 flight time type : 180 |
| ASRS Report | 342618 |
| Events | |
| Anomaly | conflict : airborne less severe non adherence : required legal separation |
| Independent Detector | atc equipment other atc equipment : unspecified aircraft equipment other aircraft equipment : unspecified other controllera |
| Resolutory Action | controller : issued new clearance other |
| Consequence | Other |
| Miss Distance | horizontal : 17000 vertical : 1300 |
| Supplementary | |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
I descended a B757 to FL330 with traffic at FL330. I meant to give the B757 FL350 and entered FL350 in the computer. No other factors were involved. I must have looked at the traffic and gave the traffic's altitude instead of the appropriate altitude. Supplemental information from acn 342618: on jul/xx/96, with ZDC (120.37) we were cleared to FL330. We were looking at a B737 visually and on TCASII at FL347 descending. ATC asked what flight level we were going to and to climb or stop climb at FL350. At FL343 we stopped and asked if it was for the traffic we were looking at. He told us no need to climb back up. There was no real conflict. The other aircraft was at FL330 and to our side. I am not sure now if ATC cleared us to FL350 or FL330 or we placed wrong altitude in the window. But we were looking at TCASII and asking ourselves (before ATC said anything) why we would be cleared to the same flight level as crossing traffic.
Original NASA ASRS Text
Title: ARTCC RADAR CTLR DSNDED A B757 TO SAME ALT AS TFC BELOW HIM, A B737. CTLR PUT CORRECT ALT OF FL350 IN DATA BLOCK, BUT SPOKE THE WRONG ALT (FL330) WHICH WAS THE B737'S ALT. B757 FLC HAD B737 IN SIGHT BOTH VISUALLY AND ON TCASII AND WHEN CTLR ASKED WHAT ALT THEY WERE DSNDING TO, HAD THEM STOP AT CURRENT ALT UNTIL CLR OF THE TFC.
Narrative: I DSNDED A B757 TO FL330 WITH TFC AT FL330. I MEANT TO GIVE THE B757 FL350 AND ENTERED FL350 IN THE COMPUTER. NO OTHER FACTORS WERE INVOLVED. I MUST HAVE LOOKED AT THE TFC AND GAVE THE TFC'S ALT INSTEAD OF THE APPROPRIATE ALT. SUPPLEMENTAL INFO FROM ACN 342618: ON JUL/XX/96, WITH ZDC (120.37) WE WERE CLRED TO FL330. WE WERE LOOKING AT A B737 VISUALLY AND ON TCASII AT FL347 DSNDING. ATC ASKED WHAT FLT LEVEL WE WERE GOING TO AND TO CLB OR STOP CLB AT FL350. AT FL343 WE STOPPED AND ASKED IF IT WAS FOR THE TFC WE WERE LOOKING AT. HE TOLD US NO NEED TO CLB BACK UP. THERE WAS NO REAL CONFLICT. THE OTHER ACFT WAS AT FL330 AND TO OUR SIDE. I AM NOT SURE NOW IF ATC CLRED US TO FL350 OR FL330 OR WE PLACED WRONG ALT IN THE WINDOW. BUT WE WERE LOOKING AT TCASII AND ASKING OURSELVES (BEFORE ATC SAID ANYTHING) WHY WE WOULD BE CLRED TO THE SAME FLT LEVEL AS XING TFC.
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.