Indigo A320 at Delhi on Feb 1st 2017, runway incursion

Last Update: June 16, 2020 / 14:53:19 GMT/Zulu time

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Incident Facts

Date of incident
Feb 1, 2017

Classification
Incident

Cause
Runway incursion

Airline
Indigo Airlines

Flight number
6E-719

Departure
Delhi, India

Destination
Vishakhapatnam, India

Aircraft Registration
VT-IEM

Aircraft Type
Airbus A320

ICAO Type Designator
A320

Airport
Indira Gandhi International Airport, New Delhi

Airport ICAO Code
VIDP

An Indigo Airbus A320-200, registration VT-IEM performing flight 6E-719 from Delhi to Vishakhapatnam (India) with 89 passengers and 6 crew, was taxiing for departure and had been cleared to taxi to holding point runway 28 via taxiway C, hold short runway 28. The aircraft however crossed the runway and stopped at the hold short line of the opposite taxiway W, where another aircraft was already waiting. The runway needed to be closed for more than one hour.

The aircraft was being pushed back opening the runway again and was subsequently able to depart with a delay of 90 minutes.

Airport sources reported the aircraft was cleared to taxi to runway 28 via taxiway C hold short runway 28, the aircraft however went past the hold short line and across the runway onto taxiway W.

The airline reported that low visibility caused the crew to miss the runway until they found themselves in a position on taxiway W unable to turn.

On Jun 16th 2020 India's DGCA released their final report concluding the probable cause of the incident ("near ground collision") was:

Under LVP conditions, the runway crossing lights from taxiway 'C' to 'W' were switched ON inadvertently by the tower controller which automatically switched OFF the taxiway 'C' curve light leading to runway 28 that led to the incident.

Contributory factors

- Absence of external visual reference due low visibility.

- Non-adherence to standard procedure of checking the correct selection of lights on the commencement of LVP by ATC.

- Lack of supervision by AGL CMS monitoring team of DIAL.

- Non-adherence to standard procedure of follow up inspection after the initiation of L VP by DIAL.

The DGCA reported the previous departure had lined up runway 28 with the assistance by a follow me vehicle. After it had successfully and without incident departed. VT-IEM was taxiing for departure during that time already. About 3 minutes later VT-IEM neared the holding point.

The DGCA reported:

At 00:22:43 UTC crew ofVT-IEM requested ATC for CAT-Ill holding lights and the same was switched ON by ATC. At 00:22:49 UTC, ATC asked VT-IEM to confirm ready for departure to which VT-IEM replied AFFIRM. At 00:22:53 UTC, ATC instructed VT-IEM to move forward to CAT-I holding point to which crew of VT-IEM asked ATC to disregard the CAT-III stop bar lights. AT 00:23:36 UTC, ATC informed that stop bar light is OFF from their side and asked VT-IEM to confirm if it is still glowing to which VT-IEM replied that it is still glowing. At 00:23:43 UTC, crew of VT-IEM informed ATC that stop bar lights has gone OFF now. At 00:24:34 UTC, ATC asked VT-IEM to line up runway 28 and at 00:25:41 UTC, ATC cleared VT-IEM for take-off runway 28. ATC informed visibil ity as 50 meters with winds 210°/03 knots and asked VT-IEM to report rolling. Thereafter, Tower Controller observed on Advanced Surface Movement Guidance & Control System (ASMGCS) that VT-IEM instead of making a right turn for line up-on Runway 28 crossed the runway and was moving towards taxiway 'W'. The Tower Controller immediately instructed VT-IEM to stop and hold position immediately.

ATC subsequently advised they were on taxiway W, there was an aircraft ahead of VT-IEM and denied a request by VT-IEM to turn right and re-iterated VT-IEM should hold position. At 00:54Z a follow me vehicle arrived, VT-IEM shut the engines down and was pushed back onto runway 28 facing into a westerly direction. At 01:19Z ATC cleared VT-IEM for takeoff from runway 28. The aircraft waiting for departure at W and "opposing" VT-IEM was able to depart at 01:21Z.

The DGCA analysed:

At the time of incident the visibility was 50 meters and low visibility procedures were in force. AGL system was on CAT-I mode since 28/01/2017 till the time of incident however LVP were enforced 4 to 5 times between this period but during all these occasions AGL system was not selected to CAT-Ill mode by the ATC. As per ATC log dated 28/01/2017, while LVP was in force, the tower controller was not able to control the stop bars in CATIll AGL selection RWY 28 and same was informed to AOCC, DIAL. Honeywell representative advised ATC to select CAT-I mode to operate stop bars. Therefore AGL was selected in CAT-I mode and manually all the CAT-Ill lights were turned ON. LVP was initiated at 18:48:00 UTC on 01/02/2018. At that time; all lights including taxiway 'C to 'W' runway crossing light were ON. As per Honeywell AGL log; at 23:21 :27 UTC, the runway crossing light between taxiway C & W were switched OFF and just after two seconds it was again switched ON which automatically resulted in switching OFF the taxiway 'C' curve light leading to runway 28 due to available interlock between these lights. At 00:25:41 UTC, VT-IEM was cleared for take-off Runway 28 by the Tower controller.

Tower controller observed on ASMGCS that Indigo aircraft VT-IEM is crossing the runway and moving towards taxiway 'W', immediately instructed Indigo aircraft to stop and hold position. Runway crossing light between 'C' and 'W' was switched OFF at 11 :53:42 UTC.

Neither ATCO nor tower supervisor/watch supervisor could notice that taxiway 'C' to 'W' runway crossing light was ON for a longer period.

The DGCA analysed:

Both the Indigo pilots have operated from RWY 28 earlier and were authorized for low visibility operations. Pilots were cautious as they were aware that another Indigo aircraft VT-IDX operating flight 6E765 which was ahead of them in sequence for take-off RWY 28 had inadvertently taxied towards taxiway 'B' instead of lining up Runway 28 via 'C'. When taxing instructions were given to the crew of VT-IEM to line up on runway 28 via taxiway 'C', they asked ATC to disregard CAT-Ill holding point stop bar lights. In absence of external visual reference due to low visibility, pilots were following the lead in lights on taxiway 'C' and did not realise that they have actually crossed the runway 28 and heading towards taxiway 'W' where the Jet Airways aircraft VT-JFY was holding at holding point. They stopped the aircraft only after getting instructions from ATC. During this period no attempt was made by the pilots to confirm their position or ask for follow me assistance till the time ATC asked them to stop and hold position. The taxing speed of VT-IEM was within the prescribed limit of 10 kts (for low visibility operations).

Further, the other pilots who operated from runway 28 via taxiway 'C' just before the incident did not inform about the misleading lighting configuration to ATC. A feedback from those pilots may have alerted the controller and incident could have been averted by taking corrective measures.

Metars:
VIDP 010200Z 25004KT 0000 R28/0150 R29/0125 FG VV/// 10/10 Q1016 NOSIG
VIDP 010130Z 26003KT 0000 R28/0175 R29/0175 FG VV/// 10/10 Q1016 NOSIG
VIDP 010100Z 24004KT 0000 R28/0150 R29/0150 FG VV/// 11/10 Q1016 NOSIG
VIDP 010030Z 00000KT 0050 R28/0175 R29/0125 FG NSC 11/10 Q1015 NOSIG
VIDP 010000Z 00000KT 0050 R28/0150 R29/0100 FG NSC 11/10 Q1015 NOSIG
VIDP 312330Z 00000KT 0050 R28/0100 R29/0100 FG NSC 11/10 Q1015 NOSIG
VIDP 312300Z 00000KT 0200 R28/0900 R29/0300 FG NSC 11/10 Q1015 TEMPO VIS 0150 FG
VIDP 312230Z 00000KT 0300 R28/1000 R29/0400 FG NSC 11/10 Q1016 NOSIG

Excerpt of Aerodrome Chart (Graphics: AIP India):