Flight IX 1134 was carrying 184 passengers and six crew when it overran the runway in heavy rain on Friday, sliding down an embankment and breaking into two main parts. The aircraft stopped around 250 feet below the runway. The flight deck crew are among the 18 who have died so far and around 15 are in critical condition.
India’s aviation ministry said that the Tower controller at the airport reports that the aircraft touched down around 1000 metres beyond the runway threshold – therefore using around one third of the runway available prior to touchdown. Some approximate calculations indicate that the aircraft would have needed the majority of the available runway to stop successfully in the prevailing conditions; but this is an estimate at this point; the report from the investigators will provide more accurate data.
The controller alerted the emergency services and asked them to follow the aircraft when he saw it land long as he thought it may well be unable to stop in the distance available. This helped to speed the response of the crash teams. There was heavy rain at the time and it is possible that the runway was flooded, which effectively means standing water on the surface. This will have a drastic effect on braking action.
I am given to understand that the runaway does not have a grooved surface to ensure drainage. The aircraft had already made one approach, into wind on runway 28 in the opposite direction. Poor visibility in the heavy rain prevented the crew from obtaining sufficient visual reference and they initiated a missed approach; repositioning for runway 10 for a second attempt. This resulted in a tailwind, which reduced the ability of the aircraft to stop within the runway available. By using 1000m prior to touchdown as well made the chances of an overrun greater.
There is anecdotal evidence that the crew began to initiate another go around but we will not know for sure until the flight data and cockpit voice recorders are analysed; they have been recovered by the authorities.
The captain was an extremely experienced pilot, who had been in the air force as well as being a test pilot and so it is a puzzle that he pressed on with the landing when he was not going to make the optimum touchdown point on the very short runway. The Boeing 737 – 800 aircraft was equipped for short field landings and both the captain and first officer were experienced at this type of operation and this airfield.
According to the Indian authorities they had sufficient fuel on board to divert to an alternate airfield and still be above minimum fuel. Once again, we may need to await and interim report from the investigators for more insight into the decision.
Some additional discussion that has arisen out of this crash is runway drainage and Boeing 737 fuselage breakups. The latter subject was sparked by a television documentary made by Al Jazeera a few years ago, called, “On a Wing and a Prayer,” alleging that Boeing’s use of lowest cost subcontractors was affecting quality. I am unable to say if these concerns are correct, although there is discussion among pilots relating to this concern. The official report may comment on this element of the tragedy.
Runway drainage may have been a factor here as well as the touchdown point and tailwind. It is common practice in many countries to build runways to shed water easily. This is achieved quite simply by creating a, “crown of the road,” shape that we are familiar with in our own roads, where the centre is slightly higher than the edges creating a curved surface. in addition, grooves are cut horizontally across the runway, to ensure that water will run off swiftly and no standing water will remain on the surface. It seems that this is not common practice in India and did not exist at Kerala.
It is hard to say that any one single element was the cause here but so often in crashes it is a collection of factors combining that creates the fatal scenario. So far as we can see they are: Landing long on an extremely wet (possibly flooded) runway, with poor braking action and with a tailwind – estimated at about 10 knots – and the result is this crash.
On the 22nd May 2010, another Air India Express Boeing 737–800 overran the runway at Mangalore after the captain ignored the First Officer’s multiple calls to, “Go Around,” as the approach was unstable and the aircraft too high. In the resultant crash, all but 8 of the 166 people on the aircraft died.
We do not yet know what calls were made in the recent crash, or who was flying the aircraft. Once the CVR and “Black Box,” data recorder are decoded the investigators will hopefully release that information at some point.