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Operational error less than standard separation when an air carrier B727 conflicts with an unknown aircraft while descending through FL223.
| Attributes | |
| ACN | 383053 |
| Time | |
| Date | 199710 |
| Day | Wed |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : mrb |
| State Reference | MD |
| Altitude | msl bound lower : 22000 msl bound upper : 22000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zdc tower : cwa |
| Operator | common carrier : air carrier |
| Make Model Name | B727 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | descent other |
| Route In Use | arrival other arrival star : star enroute : on vectors |
| Flight Plan | IFR |
| Aircraft 2 | |
| Make Model Name | Any Unknown or Unlisted Aircraft Manufacturer |
| Operating Under FAR Part | other : unknown |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp pilot : flight engineer |
| Experience | flight time total : 19000 |
| ASRS Report | 383053 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : commercial pilot : instrument |
| Events | |
| Anomaly | conflict : airborne less severe non adherence : required legal separation non adherence : published procedure other anomaly other |
| Independent Detector | aircraft equipment other aircraft equipment : unspecified other controllera |
| Resolutory Action | controller : issued new clearance other |
| Consequence | faa : reviewed incident with flight crew |
| Miss Distance | vertical : 100 |
| Supplementary | |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
On descent into bwi, on the mgw.EMI3 arrival, I was cleared to 15000 ft no delay. I began a 3000 FPM descent. At 22300 ft I was instructed 'turn right to 150 degree heading' (I had been on 100 degree heading) and 'stop descent at FL220.' as I abruptly leveled the aircraft, I quickly got a TCASII RA that first showed an intruder 300 ft below me. I hesitated about following the 'descend, descend' RA because of the display showing him to be below. The RA then changed to 'monitor vertical speed' (large red bands in both the climb and descend bands). I later telephoned the center supervisor who reported that we had passed within 100 ft. The controller's instruction to 'level the aircraft at FL220' was a grave error. The 150 degree heading was an intercept heading.
Original NASA ASRS Text
Title: OPERROR LTSS WHEN AN ACR B727 CONFLICTS WITH AN UNKNOWN ACFT WHILE DSNDING THROUGH FL223.
Narrative: ON DSCNT INTO BWI, ON THE MGW.EMI3 ARR, I WAS CLRED TO 15000 FT NO DELAY. I BEGAN A 3000 FPM DSCNT. AT 22300 FT I WAS INSTRUCTED 'TURN R TO 150 DEG HDG' (I HAD BEEN ON 100 DEG HDG) AND 'STOP DSCNT AT FL220.' AS I ABRUPTLY LEVELED THE ACFT, I QUICKLY GOT A TCASII RA THAT FIRST SHOWED AN INTRUDER 300 FT BELOW ME. I HESITATED ABOUT FOLLOWING THE 'DSND, DSND' RA BECAUSE OF THE DISPLAY SHOWING HIM TO BE BELOW. THE RA THEN CHANGED TO 'MONITOR VERT SPD' (LARGE RED BANDS IN BOTH THE CLB AND DSND BANDS). I LATER TELEPHONED THE CTR SUPVR WHO RPTED THAT WE HAD PASSED WITHIN 100 FT. THE CTLR'S INSTRUCTION TO 'LEVEL THE ACFT AT FL220' WAS A GRAVE ERROR. THE 150 DEG HDG WAS AN INTERCEPT HEADING.
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.