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ZDC controller issues descent clearance to a B737 through an occupied altitude resulting in a loss of separation with a B757.
| Attributes | |
| ACN | 579815 |
| Time | |
| Date | 200304 |
| Day | Mon |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | navaid : swl.vortac |
| State Reference | MD |
| Altitude | msl bound lower : 27000 msl bound upper : 28000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zdc.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | B737-400 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other |
| Flight Phase | descent : intermediate altitude |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | artcc : zdc.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | B757-200 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | cruise : level |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 200 flight time total : 15000 flight time type : 9000 |
| ASRS Report | 579815 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 210 flight time total : 12000 flight time type : 3000 |
| ASRS Report | 580563 |
| Events | |
| Anomaly | conflict : airborne critical non adherence : required legal separation non adherence : published procedure |
| Independent Detector | atc equipment other atc equipment : radar/mode c aircraft equipment : tcas other controllera other flight crewa other flight crewb other other : 3 |
| Resolutory Action | flight crew : took evasive action |
| Miss Distance | horizontal : 3000 vertical : 500 |
| Supplementary | |
| Problem Areas | ATC Human Performance |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
Proceeding direct swl VOR inbound to phl, ATC cleared us to descend from FL290 to FL250. Going through FL280 about 1000 FPM, we got a TA for an aircraft at about our 12:30 O'clock position that appeared to be level at FL270 coming toward us. I began to arrest our descent rate, but got an RA at FL275 or a little below. Other aircraft was about 3 NM in front of us showing 400 ft below us. I followed 'climb' advisory of about 1500-2000 FPM until clear of conflict. Leveled at FL290 after advising ATC and receiving clearance to do so. First officer saw an air carrier Y B757 pass below us to the right within a mi of us, as we were climbing. Supplemental information from acn 580563: center gave us an immediate turn. After traffic cleared, we climbed to FL280 and center cleared us to FL250.
Original NASA ASRS Text
Title: ZDC CTLR ISSUES DSCNT CLRNC TO A B737 THROUGH AN OCCUPIED ALT RESULTING IN A LOSS OF SEPARATION WITH A B757.
Narrative: PROCEEDING DIRECT SWL VOR INBOUND TO PHL, ATC CLRED US TO DSND FROM FL290 TO FL250. GOING THROUGH FL280 ABOUT 1000 FPM, WE GOT A TA FOR AN ACFT AT ABOUT OUR 12:30 O'CLOCK POS THAT APPEARED TO BE LEVEL AT FL270 COMING TOWARD US. I BEGAN TO ARREST OUR DSCNT RATE, BUT GOT AN RA AT FL275 OR A LITTLE BELOW. OTHER ACFT WAS ABOUT 3 NM IN FRONT OF US SHOWING 400 FT BELOW US. I FOLLOWED 'CLB' ADVISORY OF ABOUT 1500-2000 FPM UNTIL CLR OF CONFLICT. LEVELED AT FL290 AFTER ADVISING ATC AND RECEIVING CLRNC TO DO SO. FO SAW AN ACR Y B757 PASS BELOW US TO THE R WITHIN A MI OF US, AS WE WERE CLBING. SUPPLEMENTAL INFO FROM ACN 580563: CTR GAVE US AN IMMEDIATE TURN. AFTER TFC CLRED, WE CLBED TO FL280 AND CTR CLRED US TO FL250.
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.