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Bos tower controller witnessed conflict as arrival aircraft were making approachs to both runway 4L and runway 9; resulting in ATC directed go around.
| Attributes | |
| ACN | 668843 |
| Time | |
| Date | 200508 |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | airport : bos.airport |
| State Reference | MA |
| Altitude | msl single value : 500 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tower : bos.tower |
| Operator | common carrier : air carrier |
| Make Model Name | B747 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | descent : approach |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | tower : bos.tower |
| Operator | common carrier : air taxi |
| Make Model Name | Cessna 402/402C/B379 Businessliner/Utiliner |
| Operating Under FAR Part | Part 135 |
| Flight Phase | descent : approach |
| Flight Plan | VFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : local |
| Qualification | controller : non radar |
| Experience | controller limited radar : 12 controller non radar : 3 controller time certified in position1 : 15 |
| ASRS Report | 668843 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Events | |
| Anomaly | conflict : airborne critical |
| Independent Detector | other controllera |
| Resolutory Action | controller : issued new clearance flight crew : executed go around flight crew : took evasive action |
| Miss Distance | horizontal : 1000 vertical : 0 |
| Supplementary | |
| Problem Areas | Flight Crew Human Performance FAA Company ATC Human Performance |
| Primary Problem | Ambiguous |
Narrative:
B747 was on an ILS runway 4R approach; to sidestep to runway 4L; because runway 4R was closed for construction work; the C402 was on a visual approach to runway 9. Runway 9 and runway 4R intersect at the approach ends. The C402 was making his approach on about a 040 degree heading; then expected to s-turn to left to land runway 9. He went so wide on the s-turn to runway 9 that he ended up on a direct course of conflict with the runway 4L arrival behind him; the B747. Tower had to send the B747 around as they were on converging courses to a common point. The converging approach to runway 9 is not normal. This procedure was approved only to mitigate complaints that the construction on runway 4R and resulting delays was hurting business. To institute such a procedure on the fly; with no training for ATC; (runway 9 was the single departure runway; so others had to wait as the C402 landed runway 9) is questionable judgement at best.
Original NASA ASRS Text
Title: BOS TWR CTLR WITNESSED CONFLICT AS ARR ACFT WERE MAKING APCHS TO BOTH RWY 4L AND RWY 9; RESULTING IN ATC DIRECTED GAR.
Narrative: B747 WAS ON AN ILS RWY 4R APCH; TO SIDESTEP TO RWY 4L; BECAUSE RWY 4R WAS CLOSED FOR CONSTRUCTION WORK; THE C402 WAS ON A VISUAL APCH TO RWY 9. RWY 9 AND RWY 4R INTERSECT AT THE APCH ENDS. THE C402 WAS MAKING HIS APCH ON ABOUT A 040 DEG HDG; THEN EXPECTED TO S-TURN TO L TO LAND RWY 9. HE WENT SO WIDE ON THE S-TURN TO RWY 9 THAT HE ENDED UP ON A DIRECT COURSE OF CONFLICT WITH THE RWY 4L ARR BEHIND HIM; THE B747. TWR HAD TO SEND THE B747 AROUND AS THEY WERE ON CONVERGING COURSES TO A COMMON POINT. THE CONVERGING APCH TO RWY 9 IS NOT NORMAL. THIS PROC WAS APPROVED ONLY TO MITIGATE COMPLAINTS THAT THE CONSTRUCTION ON RWY 4R AND RESULTING DELAYS WAS HURTING BUSINESS. TO INSTITUTE SUCH A PROC ON THE FLY; WITH NO TRAINING FOR ATC; (RWY 9 WAS THE SINGLE DEP RWY; SO OTHERS HAD TO WAIT AS THE C402 LANDED RWY 9) IS QUESTIONABLE JUDGEMENT AT BEST.
Data retrieved from NASA's ASRS site as of January 2009 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.