THIRUVANANTHAPURAM: Two days after the Aircraft Accident Investigation Bureau (AAIB) launched an investigation into the plane crash at Kozhikode airport on August 7, fresh evidence that emerged during inspection countered the claims of aquaplaning and rubber deposits on the runway.
Soon after the mishap, various quarters, including sources from the airline, had said excessive rubber deposits on the wet runway were the main reason for the aircraft overshooting the strip.
Rubber deposits in the touchdown zone of the runway used to be cleared regularly as these are considered one of the primary causes of reduction of friction when runways are wet.
But when an aircraft skids off the runway due to excessive rubber deposits in the zone, it would leave deep black marks on the surface.
The investigation officials who checked the runway couldn’t find any rubber traction marks, said a source.
Second, hydroplaning, in which the tyres are lifted off the surface by the action of the fluid trapped between wheels of the aircraft and runway surface, would leave a brown mark on the surface due to the excessive heat generated. During probe, the officials couldn’t find any such marks on the runway. The friction characteristic of the runway is also within the accepted level.
Normally, the airport handles around 45 departures and arrivals per day, while after evacuation flight services began, the airport has been handling, on average, 10 aircraft per day.
It shows that the chances of accumulation of excessive deposits on the runway are very low compared with normal traffic.
The rubber deposit occurs normally in the touchdown zone as the landing wheels of the aircraft hit this area. But in this case, the aircraft landed well beyond the touchdown zone.
It is also learnt that the investigation team will probe the crew resource management (CRM) of the airlines. Ineffective CRM is listed as a contributing factor leading to a crash.
In the Mangaluru plane crash, the probe report pointed out the lack of CRM due to the mixed culture of pilots.
There was no conversation between the two pilots for a long time during their flight. Here, the captain was an ex-IAF Wing Commander and the co-pilot was a 32-year-old junior pilot.