ASN Wikibase Occurrence # 318264
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Date: | Saturday 7 October 2017 |
Time: | 18:24 UTC |
Type: | Boeing 777-3D7 |
Owner/operator: | Thai Airways International |
Registration: | HS-TKC |
MSN: | 29211/250 |
Year of manufacture: | 1999 |
Fatalities: | Fatalities: 0 / Occupants: 258 |
Aircraft damage: | None |
Category: | Serious incident |
Location: | near Delhi-Indira Gandhi International Airport (DEL/VIDP) -
India
|
Phase: | En route |
Nature: | Passenger - Scheduled |
Departure airport: | Delhi-Indira Gandhi International Airport (DEL/VIDP) |
Destination airport: | Bangkok-Suvarnabhumi International Airport (BKK/VTBS) |
Investigating agency: | AAIB India |
Confidence Rating: | Accident investigation report completed and information captured |
Narrative:Thai Airways International flight TG316, a Boeing 777-3D7 (HS-TKC), and British Airways flight BAW143, a Boeing 787-9 (G-ZBKF), were involved in a serious airprox incident.
British Airways flight BAW143 from London to Delhi was established on ILS runway 29. The aircraft changed over to Tower South Controller at approximately 10 NM from touchdown. BAW143 was observed to be reducing speed from 205 Kts at 20 Nm from touch down, 194 kts at 12 Nm from touch down, 185 kts at 10 Nm from touch down,183 Kts 7.5 Nm from touch down and 176 kts at 5 Nm from touch down. The inter arrival spacing between BAW143 and the preceding arrival, an Airbus A321 aircraft flight AIC014 was observed to 6.5 NM with the speed of preceding aircraft as 140 kts and succeeding aircraft (BAW143) as 200 kts.
The inter arrival spacing between arriving flight BAW143 and departing Thai flight THA316 was 6NM, when THA316 was lining up. This inter arrival spacing was actually further reduced and was approximately 5.27 NM, taking into consideration the high speed of BAW143, the displaced threshold of runway 29 by 1460 m and the CE2 intersection departure (110 m from beginning of runway 29) by THA316.
The Aerodrome Controller without taking into consideration the speed of arriving BAW143, the reduced inter arrival spacing and displaced threshold of runway 29 lined up and cleared the departing THA316 for a CE2 intersection takeoff. The departing THA316 also took some time on the runway before commencing takeoff roll.
In the meantime, the arriving BAW143, which was approaching the threshold of runway 29, initiated missed approach at less than 1 NM from touchdown (approximately from the beginning of runway 29).
This simultaneous going around of the BAW143 and the departure of THA316 from runway 29 resulted in the breach of standard separation. The lateral and vertical separation was reduced to less than 1 NM and 200 feet respectively. The departing THA316 was restricted in climb to 2600
feet and changed over to approach arrival (APAC) controller. The going around aircraft, BAW143 was asked to expedite climb to 3600 feet and in coordination with approach arrival radar controller, given a left heading of 180. BAW143 was changed over to approach arrival radar (APAC).
Thereafter the flights were uneventful.
Probable Cause
Non-adherence to the Standard Operating Procedures by the Aerodrome Controller.
Contributory Factors
1. Failure of Approach Radar Controller to provide adequate inter arrival spacing and to apply speed control methods on the arriving aircraft.
2. Failure of the Crew of flight THA 316 to adhere to the published departure procedures.
3. Failure of Crew of flight BAW143 to adhere to the published speed control norms.
Accident investigation:
|
| |
Investigating agency: | AAIB India |
Report number: | |
Status: | Investigation completed |
Duration: | |
Download report: | Final report |
|
Sources:
AAIB India
Revision history:
Date/time | Contributor | Updates |
22-Jul-2023 07:11 |
harro |
Added |
22-Jul-2023 07:12 |
harro |
Updated |
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