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Journalism of Courage
There is no reason to ring alarm bells but the increasing congestion in air traffic — almost a 29 per cent jump in traffic last year alone — has also been accompanied by an increase in the number of “air misses.”
While it is only the odd air miss, involving a VVIP flight, that gets publicised, the Directorate General of Civil Aviation (DGCA) has replied to a Right to Information request filed by The Sunday Express that on an average, there were two such incidents each month last year involving virtually all carriers, public and private — and Indian Air Force aircraft.
The standard definition of an air miss is when two planes flying below 29,000 feet breach the mandatory 1000-feet separation limit. Above 29,000 feet, the limit is also 1000 feet for aircraft that have Reduced Vertical Separation Minima (RVSM) equipment which include Transport Collision Avoidance System (TCAS), special altimeters and transponders. Those not RVSM-complaint have to maintain a separation of 2000 feet. Incidentally, all passenger aircraft are now RVSM-compliant.
The Indian Air Force is working to upgrade its VVIP fleet Boeings to RVSM.
Detailed data on air misses for five years — from 2002 to 2006 — show that there have been 83 reports of such air encounters and that over 15 such incidents have already occurred in 2007. Between 2002 and 2005, there were only two air misses involving IAF aircraft — with Turkmenistan Airlines and Indian Airlines in 2003 — but in 2006 alone, the IAF was involved in six such episodes. While one of these six was an air miss involving two IAF AN-32s, the other incidents involved aircraft of Jet Airways and Indigo Airlines.
Technically, DGCA doesn’t distinguish between “air misses” and the more serious “air proximity” incidents where pilots, after having breached the separation limit, are also on “converging tracks and in eyeball-to-eyeball contact.”
Officials said the “ratio” of air misses to traffic volume compares well with that of several other countries but the increasing trend is a matter of concern.
DGCA chief Kanu Gohain told The Sunday Express: “All air misses reported in the media are not necessarily air proximity incidents but each of them is investigated by us to devise mitigating methodology to see that such incidents do not occur frequently.”
In the list of 83 incidents, DGCA puts four as “air proximity” incidents:
• September 21, 2006: Indian Air Force aircraft and Jet Airways Flight (9W-345) were on a collision course.
• March 10, 2006: Sri Lankan Airlines (ALK192) and Jet Airways (JAI1826) had violated the separation limit.
• March 12, 2005: Jet Airways (JAI-424, B737) and Emirates Airlines (UAE-502, A-330) were flying close, on converging tracks.
• Jan 23, 2005: Air India carrier (AIC-348 A-310) was flying on a head-on track with an IAF Sukhoi which was part of a Trishul formation.
DGCA officials said several remedial steps have been taken to reduce the number of “air misses.” For one, DGCA has made it mandatory for airplanes to be equipped with an Transport Collision Avoidance Systems; mono pulse Secondary Surveillance Radars have been installed at major airports to provide Air Traffic Controllers with information of aircraft altitude and Minimum Safe Altitude Warning (MSAW) systems have been installed to send out warnings whenever an aircraft descends below the minimum separation limit.
