Near collision of IndiGo, Silk Air planes, govt launches probe

Two IndiGo and SilkAir planes were involved in a near-miss over Kolkata airspace last December, it has emerged, prompting the government to launch a probe.
The IndiGo plane from Kolkata to Hyderabad (VT-IEM) and the Kolkata-bound SilkAir aircraft from Singapore (9VMGH) were involved in the incident that happened on December 11.
Together, there were more than 200 people in the two planes. Both the airlines did not provide the number of passengers who were on board their respective flights when the incident happened.
Aircraft Accident Investigation Bureau (AAIB) has started a formal inquiry into the "serious incident", according to a recent notification issued by the Civil Aviation Ministry.

Citing preliminary data from Indian authorities, French aviation watchdog BEA said vertical separation between the two aircraft "was zero feet" while the least horizontal separation between the two planes was reduced to just 0.6 NM.
About the incident, an IndiGo spokesperson said there was a reduction in horizontal separation between the two aircraft but "no error has been found on part of the IndiGo flight crew".

The airline also said the situation could have been avoided had the Air Traffic Controller (ATC) not cleared its plane for take-off and made SilkAir discontinue the approach.
When contacted, a SilkAir spokesperson said the airline has provided AAIB with all the information and reports for the flight to aid them in their investigation.

In a statement sent to PTI, the spokesperson said as the SilkAir aircraft was on approach and preparing to land, it was alerted about the Indigo plane taking off from the same runway.
As the pilots could not clearly identify the location of the IndiGo aircraft on the runway, they decided to discontinue the approach and circle the airport for another approach to land, the statement said.
The SilkAir plane landed safely, it added.
IndiGo was flying Airbus 320 plane while SilkAir was operating Boeing 737 aircraft.
The seating capacity is around 180 seats and 162 seats for the IndiGo and SilkAir planes, respectively.

A senior official at aviation regulator DGCA said it has received information about the incident and AAIB probe is on.
BEA said "IndiGo flight IGO6619 sector Kolkata-Hyderabad departed runway 19L at 1525 UTC while the SilkAir flight MI488 commenced go around at the same time."
"The least horizontal separation between MI488 and IGO6619 was 0.6 NM during the entire event and the least vertical separation was zero feet," as per information available on BEA website.
BEA has also mentioned that it is "preliminary data based on the notification from the authorities of India".
IndiGo said the incident occurred when its flight was

given backtrack on runway 19L at Kolkata, and at the same time Emirates 777 was given line up from taxiway K and cleared for take off.
During this time, the SilkAir aircraft was around 5-6 miles from touchdown and as the Emirates plane delayed its take-off that led to a situation wherein IndiGo airplane's departure was also delayed, it added.
"By the time Emirates took off and IndiGo commenced take off roll after cleared by Kolkata ATC, SilkAir aircraft was around 2 miles to touchdown.
"IndiGo aircraft took off and followed all instruction of ATC. SilkAir aircraft carried out a go around. This led to a situation of reduction in horizontal separation between the two aircraft," IndiGo said.

Further, the airline noted that no TCAS (Traffic Collision Avoidance System) caution or warning triggered in either aircraft but this reduction in horizontal separation was a breach of ATC norms.
Generally, TCAS warning is triggered when an aircraft is in proximity of another one.
"Last known information, the said controller was put off duty. No error has been found on part of the IndiGo flight crew. This situation could have been avoided in case the ATC controller would have not cleared IndiGo aircraft for take off and made Silk Air discontinue the approach," it said.
Ordering AAIB probe, the ministry said, "It appears to the central government that it is expedient to investigate and determine the causes and contributory factors leading to the said serious incident and make recommendations to avoid recurrence of such serious incidents in future."

The committee, headed by AAIB Assistant Director Jitender Loura, has Assistant Director Raje Bhatnagar and Air Safety Officer Dinesh Kumar as members is probing the incident.
Whenever required, the panel can take the assistance of other experts and agencies.
Meanwhile, IndiGo said most events of breach of separation is due to implementation of "High Intensity Runway Operation" wherein the ATC controllers are having difficulty coping up with the increase in air traffic due to lack of sophisticated radars.
SilkAir -- part of Singapore Airlines group -- also said it always takes the safety of passengers and crew seriously, and ensured that all relevant procedures are reinforced.