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A B757 PIC delays his RA governed descent from 3000 ft and has a potential conflict with traffic 20 mi southeast of bwi, md.
| Attributes | |
| ACN | 477755 |
| Time | |
| Date | 200007 |
| Day | Sat |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | airport : bwi.airport |
| State Reference | MO |
| Altitude | msl bound lower : 2500 msl bound upper : 3000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tracon : bwi.tracon |
| Operator | common carrier : air carrier |
| Make Model Name | B757-200 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other |
| Flight Phase | descent : intermediate altitude |
| Route In Use | arrival : on vectors |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | tracon : bwi.tracon |
| Make Model Name | Any Unknown or Unlisted Aircraft Manufacturer |
| Flight Phase | cruise : level |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 150 flight time total : 6500 flight time type : 1200 |
| ASRS Report | 477755 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : flight engineer pilot : atp |
| Experience | flight time last 90 days : 50 flight time total : 15000 flight time type : 2000 |
| ASRS Report | 477424 |
| Events | |
| Anomaly | airspace violation : exit conflict : airborne critical non adherence : far non adherence : published procedure non adherence : required legal separation other anomaly other |
| Independent Detector | atc equipment : conflict alert aircraft equipment : tcas other controllera other flight crewa |
| Resolutory Action | controller : issued alert flight crew : took evasive action |
| Consequence | faa : reviewed incident with flight crew |
| Supplementary | |
| Problem Areas | ATC Human Performance Airspace Structure Flight Crew Human Performance |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
On normal vectors for approach to runway 33L baltimore (bwi). At 3000 ft MSL heard supervisor get on and give emergency vectors to another aircraft. At same time we got TA on TCASII. Looked down and saw yellow traffic co-altitude at edge of scope go quickly from 3 O'clock position to 6 O'clock position and went off scope at 6 O'clock position. Shortly after we got a descend, descend now RA. Captain (PF) clicked off autoplt and delayed descent saying 'he's not on scope -- I can't see anything.' I said to 'descend.' shortly after TCASII gave us an 'increase rate of descent.' captain started descent. I notified ATC and we were told traffic has you in sight. We got a clear of conflict report after that. My concern: captain (PF) delayed descent in response to an RA because he 'didn't have conflict in sight nor was conflict apparent on scope.' my response is that there might be a pop up traffic you are getting the advisory for -- not the traffic that just went off scope. Delaying descent until you have traffic in sight may create a worse conflict. Supplemental information from acn 477429: ATC was told we were leaving assigned altitude (3000 ft) because of TCASII advisory.
Original NASA ASRS Text
Title: A B757 PIC DELAYS HIS RA GOVERNED DSCNT FROM 3000 FT AND HAS A POTENTIAL CONFLICT WITH TFC 20 MI SE OF BWI, MD.
Narrative: ON NORMAL VECTORS FOR APCH TO RWY 33L BALTIMORE (BWI). AT 3000 FT MSL HEARD SUPVR GET ON AND GIVE EMER VECTORS TO ANOTHER ACFT. AT SAME TIME WE GOT TA ON TCASII. LOOKED DOWN AND SAW YELLOW TFC CO-ALT AT EDGE OF SCOPE GO QUICKLY FROM 3 O'CLOCK POS TO 6 O'CLOCK POS AND WENT OFF SCOPE AT 6 O'CLOCK POS. SHORTLY AFTER WE GOT A DSND, DSND NOW RA. CAPT (PF) CLICKED OFF AUTOPLT AND DELAYED DSCNT SAYING 'HE'S NOT ON SCOPE -- I CAN'T SEE ANYTHING.' I SAID TO 'DSND.' SHORTLY AFTER TCASII GAVE US AN 'INCREASE RATE OF DSCNT.' CAPT STARTED DSCNT. I NOTIFIED ATC AND WE WERE TOLD TFC HAS YOU IN SIGHT. WE GOT A CLR OF CONFLICT RPT AFTER THAT. MY CONCERN: CAPT (PF) DELAYED DSCNT IN RESPONSE TO AN RA BECAUSE HE 'DIDN'T HAVE CONFLICT IN SIGHT NOR WAS CONFLICT APPARENT ON SCOPE.' MY RESPONSE IS THAT THERE MIGHT BE A POP UP TFC YOU ARE GETTING THE ADVISORY FOR -- NOT THE TFC THAT JUST WENT OFF SCOPE. DELAYING DSCNT UNTIL YOU HAVE TFC IN SIGHT MAY CREATE A WORSE CONFLICT. SUPPLEMENTAL INFO FROM ACN 477429: ATC WAS TOLD WE WERE LEAVING ASSIGNED ALT (3000 FT) BECAUSE OF TCASII ADVISORY.
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.