On 27 February 2016, an Airbus A320 (VT-IGK) being operated by Indigo on a scheduled domestic passenger flight from Ahmedabad to Jaipur as 6E-237 discontinued its initial day VMC visual approach to runway 27 at destination when an EGPWS ‘TOO LOW TERRAIN' Alert was annuniciated at a low level after the aircraft had lined up on a road parallel to the runway. Positioning to a second approach, this time using the ILS LLZ, was followed by a landing and was without further event.
The road mistaken for the runway by the Captain. [Reproduced from the Official Report]
An Investigation in accordance with Annex 13 principles was carried out by Indian DGCA. The FDR was recovered from the aircraft and its data were successfully downloaded but the CVR was not removed because the initial report of the event described it only as a “go-around due to triggering of a GPWS warning”.
The 49 year-old Captain had a total of 6,791 flying hours experience including 3,941 hours on type of which 870 hours had been in command on type. He had joined Indigo at the age of 44 after prior service as a military pilot. The 27 year-old First Officer had a total of 1,577 hours flying experience, all but 260 hours of which had been on type. He had qualified as a First Officer in 2011 and had been employed by Indigo since then.
It was established that with the First Officer as PF, the flight was advised by Jaipur APP to expect an ILS LLZ approach to runway 27 and the Captain then “briefed and planned” for the corresponding procedural approach via the overhead. When around 35 nm from Jaipur, APP advised that the visibility was 5000 metres and offered the option of a visual approach which was accepted. On reporting “field in sight”, the flight was cleared for the visual approach and (since it would be joining the circuit downwind left hand) was instructed to report on left base for runway 27 and transferred to TWR.
The aircraft subsequently joined downwind at 2700 feet amsl with AP2 engaged and the selected speed as 180 knots and flaps 1. After flying downwind for one minute to a position approximately 4nm from the runway threshold, the AP was disengaged, gear down and flap 1 were selected and the base turn was made. As the aircraft rolled out of the base turn, both pilots began looking for the runway and almost immediately, the Captain called “runway in sight" and instructed the First Officer to descend, although the First Officer did not yet have runway contact. Flap 3 was selected as descent at a maximum of 1000 fpm was maintained for approximately half a minute. A turn onto finals was made when around 4½ nm from the threshold with the aircraft at 1000 feet agl and the airspeed at the applicable VAPP of 140 KCAS. During this turn, the First Officer still did not have the runway in sight and followed the Captain’s instructions as the forward visibility TCF deteriorated due to the setting sun being directly ahead.
When the First Officer eventually sighted the runway at 500 feet agl, he realised that “what Captain was assuming to be runway was a straight road” and he was being asked to descend with reference towards this road rather than the runway. His alerts to the Captain that this was not the runway were apparently ineffective and FDR data indicated that at 200 feet agl with 1.27 nm to go to the threshold, an EGPWS ‘TOO LOW TERRAIN’ Alert was triggered based on the Terrain Clearance Floor (TCF) function. An immediate go-around was initiated by the First Officer at a recorded 189 feet agl and the aircraft was then positioned for a second approach. This time, the ILS LLZ which had not been displayed during the first approach was used and the flight was subsequently completed with a normal landing.
The Captain stated that it was about two years since he had last operated into Jaipur and that he “was not aware of any road to the south of the runway”.
The Investigation made a number of observations on the facts gathered which are summarised as follows:
- It was noted that whilst there was “no defined circuit pattern or circuit altitude at Jaipur”, the aircraft operator did have clear guidance on how a visual circuit should be flown which included being downwind at 1500 feet aal.
- The crew flew an extended downwind leg which did not conform to the ‘Visual Approach’ procedure prescribed in the operator’s OM and Flight Crew Training Manual (FCTM). Also, on the downwind leg, the First Officer as PF was entirely reliant on the Captain to advise when the aircraft was abeam the landing runway threshold so that he could ensure the appropriate timing to the base leg turn but no evidence was presented that this call was made.
- Although the visibility was “well above the minimum for a visual approach”, the crew overlooked the fact that the approach would be into sun which would affect their ability to see the runway. They then disregarded the SOP advice to back up a visual approach with any available radio navigation aids, in this case the ILS LLZ which would have ensured they made their final approach on the runway extended centreline.
- The fact that the First Officer appears more than once to have pointed out the runway when he first saw it but continued the approach in accordance with guidance from the Captain was considered to indicate a lack of assertiveness on the part of the First Officer and a corresponding lack of receptiveness on the part of the Captain. It was observed that with effective CRM in place, “if something does not look correct the observing crewmember bears responsibility for communicating what they see - the key behind successful CRM is being receptive, informative, proactive, and persistent”.
- In the event that a go-around becomes necessary whilst the Captain is acting as PM, he is required to call “I have control” and take over and the other pilot must acknowledge by announcing “you have control” whilst continuing to fly the aircraft until a positive input is made by the Captain. This requirement was ignored.
- In respect of the road mistaken for the runway by the Captain, this was identified as being 60 metres wide and 380 metres to the left of the centreline of the 45 metre-wide runway. This road was a dual carriageway, was not straight and had traffic lights at intervals along its length. The 45 metre runway had centreline marking in addition to threshold, TDZ and edge markings.
The Cause of the Serious Incident was determined as "the Captain misidentifying a road parallel to and short of the runway as the runway and his failure to order a go-around despite the First Officer (PF) saying, more than once, that (the Captain was not looking at the runway)”.
Four Contributory Factors were also identified as follows:
- The crew decision to carry out a visual approach to runway 27, knowing that the setting sun would impair their visibility.
- The failure of crew to use ILS as a back-up while doing the visual approach, especially with the sun into their eyes.
- Both pilots were operating to Jaipur after a long gap.
- A lack of assertiveness on the part of the First Officer even when he did not have runway in sight and a non-receptive Captain when he did.
The Final Report was completed on 8 January 2019 and subsequently released during February 2020.