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Archive for February, 2018

Air India-Vistara near miss: Lack of aviation awareness triggers blame games

with 10 comments

By OV Maxis
Deputy General Manager (ATC)
Airports Authority of India
Going  through the reports of the February 7th Air India-Vistara air-prox incident, it can be seen that that the Area Controller at Mumbai had descended UK997, Delhi-Pune Vistara flight to 29000ft and had given permission to AI631 Delhi-Mumbai Air India flight  to climb only up to 27000ft to keep them vertically separated enough. What made the Vistara pilot to descent below the cleared level is still not evident. As the matter is under investigation it will be inappropriate to draw inferences. However, a listening error on the part of the pilot/ controller cannot be ruled out. The ATC tape replay can reveal the truth.


It has become a common practice for the journalists to put the blame on ATC blatantly in any incidents where ATC personnel are involved without going fully through the details and circumstances.


The attempt to glorify the lady commander of Air India is liable to be viewed as reciprocation from the journalist for leaking out the confidential information. Poor awareness of civil aviation of the journalist who covered the story is also evident from the report. It has become a common practice for the journalists to put the blame on ATC blatantly in any incidents where ATC personnel are involved without going fully through the details and circumstances. In this case also the ATC was projected as the villain and the lady commander as a heroine

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Read also:
An incident story that turned into an accident
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Even if the lady co-pilot of the Vistara airline committed some mistake, she deserves equal appreciations as received by the Air India lady commander (from the media). Why because, she was very alert and responded to the resolution advisory of the Traffic Collision Averting System(TCAS) in no time as evidenced from ADS-B pictures.

TCAS is the last resort to the pilot to avert a mid air collision in the event of ATC/pilot error. The pilots get visual indication of the conflicting traffic as early as 60 seconds (20NM) laterally and at about 6000 ft vertically in blue color on the cockpit display. When the intruder traffic is within 40 seconds and vertically below 850ft, display changes to yellow and pilot get a warning (Traffic alert). when collision is imminent. 25 seconds before (vertically 650ft), pilot receive RA along with audio instruction to climb or descend. The pilot is expected to act within 5 seconds and follow the RA instruction. Following RA collision can very well be avoided.


Now who is the real heroine?
The co-pilot of Vistara who handled the situation alone or the much more experienced lady commander of Air India who had the assistance of a co-pilot in the cockpit?


In this particular case both the lady pilots meticulously followed the RA instructions generated by the TCAS. In fact, the Vistara pilot executed a rapid descend and played an equal or a better role in avoiding the collision. In spite of receiving an instantaneous RT communication from the controller blaming her actions at that critical moment, she kept the presence of mind and immediately executed the steep descend warranted by RA. Considering the fact that at the time of the incident she was the only pilot available in the cock pit as the commander was away in the toilet she really deserves an appreciation for the most crucial emergency action and thereby avoiding a possible collision.

Now who is the real heroine, whether it is the co-pilot who handled the situation alone or the more experienced lady commander of Air India who had the assistance of a co-pilot in the cockpit?

If tomorrow, the investigations absolve the Vistara lady pilot of any violation of ATC clearance, she will emerge as a real heroine. Let us watch. These are only a public perception under the influence of a biased media. The real fact is that both have discharged the call of their normal duties and responsibilities in such an emergency situation. They are trained and rated for these kind of emergency responses.

And something more about the ATCOs who often portrayed in bad light in media reports like this:

There is a system in place in every ATC units to record the control instructions and radar situation display to facilitate future the investigation if required. The purpose of the investigation itself is to identify the deficiencies in the system and to prevent its reoccurrence. ATCOs undergo stringent and regular skill/ proficiency/performance tests to keep the currency of their ATC ratings. No inferior controllers are rated and deployed on channels.

And one should also not forget the fact that an ATCO may have to control 20 to 30 aircraft at a time in a very congested airspace like Mumbai He has to resolve multiple conflicts of air traffic on different routes/ locations at a time. He is working under severe stress as there is no scope for any error in the decisions he takes in split seconds.

Mistakes can happen at times as he is also a human being but as said above, he is very much accountable for his mistakes.

(OV Maxis is an air traffic, aviation safety expert with more than 30 years of experience. He can be reached at ovmarxis@yahoo.com)
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Written by admin

February 17th, 2018 at 9:15 am

Posted in Uncategorized

An incident story that turned into an accident

with 12 comments

By Jacob K Philip

A near miss incident involving a Vistara Delhi -Pune flight and an Air India Mumbai-Bhopal flight could be one of the most discussed and widely reported aviation incidents recently in India. Though the report that was carried first by Times of India on 11th of this month and later taken up by most of the national and regional press has brought aviation safety to sharp focus again, it raises more questions on how safety issues like this are reported and interpreted by the media.

And it is also of concern that the whole details of the incident were leaked to the press by one or two  central government organizations and the press thereafter presented  it  to the public in the most unprofessional and unethical manner.

The is a gist of the report(s):

On February 7, night  an Air India flight (Mumbai to Bhopal AI 631, an Airbus A 319-112) was travelling at 27,000 ft towards Bhopal.  A Vistara flight (UK997, Airbus A320-251N) that was inn the same skies flying towards  Pune from Delhi at 29,000 feet suddenly started descending to 27,000. The astonished area controller asked the Vistara why it left the assigned level of 29,000 and going to 27,000 and the pilot of the craft retorted that she was told by the controller to do so. The argument was heard by the AI pilot too, because She too was tuned to the same frequency. Then to her horrors,  the AI commander noticed  the Vistara flight speeding towards her flight just 2.8km away. Then the Traffic Collision Avoidance System (TCAS) of both the aircraft issued a very urgent collision warning (resolution advisory). The warning said, “climb, climb” to the AI  flight and the pilot climbed up and turned right immediately to fly clear of Vistara, to escape the doom that was imminent. The level difference between two flights was just 100ft before AI flight climbed up, as per TCAS. When their paths crossed each other , the level difference was just 600ft. Whereas, the allowed minimum vertical separation was 1000ft.

The original reports published by the Times of India on two consecutive days and the rehash of those reports by the rest of the national media made the readers think that:

  1. The two aircraft were traveling in opposite directions
  2. Both aircraft were maintaining their respective levels- 27,000 and 29,000 feet – cruising along peacefully until the Vistara started descending from 29,000 to AI flight’s 27,000 level.
  3. It was the presence of mind Air India pilot that saved the lives of as many as 271 people on board of both aircraft. She acted precisely and swiftly when faced by a life threatening eventuality.
  4. But for the AI pilot, the two aircraft would have collided each other, face on.

But the actual facts couldn’t have been more different:

  1. Direction of the fights: The aircraft were not traveling face to face towards each other. At the time of conflict, the angle made by the flight paths of two aircraft were apporx 120 degrees – not 180. See the picture.
  2. No level flight: After taking off at 7.40 PM from Mumbai airport, the Air India aircraft was still in the climbing phase of the flight (It had to reach the cruising altitude of 33,000ft within a few minutes) and so it was gaining around 1000-1500 feet per minute, consistently.

And the Vistara flight, that had left Delhi 6.50PM was steadily losing altitude for a landing at Pune airport at 8.52PM.

Bothe aircraft were NOT staying at any particular altitude. One was climbing, the other was descending.

See altitudes of Air India flight 631 was maintaining before and after the incident (From 23,600 to 28,300 ft)  (Log from flight tracking site Flightaware).

  • At 08:28:23pm  23,600ft
  • At 08:28:54pm  24,600ft
  • At 08:29:24pm  25,100ft
  • At 08:30:01pm  25,800ft
  • At 08:31:00pm  27,200ft
  • At 08:31:40pm  27,400ft
  • At 08:32:40pm  27,800ft
  • At 08:33:07pm  28,300ft

And these were Vistara flight’s levels :

  • At 8:28:18pm  31,500ft
  • At 8:28:49pm  31,000ft
  • At 8.29:19pm  30,200ft
  • At 8.29:49pm  29,300ft
  • At 8.30:19pm  27,800ft
  • At 8.30:49pm  27,000ft
  • AT 8.31:38pm  26,600ft
  • At 8:32:09pm  26,600ft
  • At 8:32:43pm  26,800ft

So here we have two flights traveling at two level s heading to two destinations and whose flight paths were to be crossed at some point of time.  And just as it was the only logical step, the descending aircraft was told by the Mumbai Area Control to stay above and the climbing one to stay below, so that they could be allowed to pass each other at the first safest point of time when the vertical and lateral separation between the two was safest.
And to repeat that again, it was only natural for the Vistara flight to climb down sooner or later.

  1. The pilot who braved odds to save lives?
    Not really. The pilots of both the aircraft were just obeying the orders issued by the computer of TCAS of their respective aircraft. The AI commander climbed up because the TCAS decided that was better and ordered her to do so. Just like the Vistara co-pilot, who lowered her aircraft as per the TCAS command. And there was nothing marvellous in these actions either. All the pilots are thoroughly trained to do that and they are bound to follow the exact procedure. And the decision maker is not the pilot, but the TCAS computer. The course of action is decided collectively by the TCAS computers of both the planes after assessing the speed, altitude, mode of flight and bearing of both the planes.  And when the computers issue the verbal command ( to climb or to descend, mostly) the pilots have no choice but to obey blindly.
  2. A certain doom scenario? The chances of a collision was less, though the TCAS had ordered the pilots to climb/descend immediately. Even if the planes  were proceeded in the same levels maintaining the same speed,  the chances of actual collision were remote.

See the pictures that show the full flight paths of the aircraft and the enlarged view of the point where the Resolution Advisory was given by the TCAS around 8.30pm, 7th February.

One aircraft was at 27,000ft and the other was at 27,100ft altitude. The speed of the Air India flight was 1080km/hr. The Vistara flight was covering 763 km in an hour. The lateral separation between the flights was 2.8km. The bearing of Vistara flight was 177 degrees and that of AI was 74 degrees, approx.

If we draw two lines extending the path of both the aircraft, it can be seen  that  they would cross  each other at a distance of 2km (down) from the present position of Vistara fight. To reach that point, the time  taken by Vistara would have been 9 seconds. But during those 9 seconds, AI flight would  been moved 3.9km away from its present position.
So there were no collision going to happen.

But then what about the TCAS urgent warning?  Can computers go wrong?

The computers of course were not wrong. Only that, these systems always incorporate a factor of safety in all calculations. An extra allowance will be added to all the distances and heights. And that is how it should be.

The Area Controller factor

In the sensationalized report of Times of India, this character got only a passing mention – but that was damaging enough.  According to the report, the AC was taken by surprise  ‘seeing’ the Vistara fight at level 271.  The question the AC reported to have asked the Vistara pilot – “why are you here?”-  betrays his total lack of control over his job. A person constantly monitoring the flight can’t be taken off guard like that.  So he indeed was a villain, though not the main one, in the story.

The main villain and the heroine

And about the main one, there were enough ingredients- lucky for the reporter- to spice up the  whole thing: the co-pilot was a woman; she was alone; her Commander was not anywhere near at the critical moment.  A young, in experienced, ignorant girl of a pilot left  alone to find her way out of the mess she had made was the perfect dark background for the heroine of the story.
And what a heroine it was to be !

– A mature, elegant woman in her late forties with 20 years of flying experience under her belt, the Air India commander was the perfect picture of the cool, composed superwoman who averts imminent disaster at the nick of time.

So we have the day-two story:

Near miss: How AI’s woman pilot saved lives of 261 flyers

And it will be highly inappropriate to end this note without mentioning an effort actually made by the ToI reporter to guess why there was a ‘confusion’ between the Vistara flight  and the AC.

” There may have been confusion between the ATC and Vistara cockpit — which at that time had a woman co-pilot at the controls and the captain had taken a toilet break. The AI flight had a woman commander, Captain Anupama Kohli. Maybe there was a mix-up in communication in those tense seconds like what altitude instruction is being given to which lady. This has to be seen,” said sources.”

So the assumption is that the AC got confused between the two woman voices.  It is sad that the reporter didn’t pause for a second to think about the numerous male voices an AC hears throughout the day from the cockpits of so many flights, without confusing among them.  Before writing down this silly guess, the reporter should have tried to understand a basic norm too of radio communication : Before the start of each instruction, the controller has to spell  the call-sign of the aircraft he is giving the instruction. And when the pilot replies, she/he also has to say his call-sign at the end of his words. And above all, the aircraft is constantly being  monitored visually on the radar screen, by the AC at the Area Control.

The leak

How the details of the incident found their way to the media is intriguing, to say the least.

In both the reports,  there were details that were known only to the people directly involved in the incident and to the officials of DGCA who had received reports from the parties involved – the facts that the Vistara co-pilot and Air India commander were women and the Vistara male commander was taking a toilet break during the incident are examples.

The AC , AAI and the Vistara crew  would not have leaked the info, for obvious reasons.  The remaining parties are the Air India crew and the DGCA.  Given the heroine status given to and readily accepted by its senior pilot, Air India of course is the chief suspect.  And they couldn’t have done that alone.  The other half of the story unfolded the night of 7th February aboard the Vistara flight must have been filled in by someone who had access to the report Vistara sent to the DGCA.

But why?
Why should someone from Air India and/or DGCA take the pains to give these details to the press? Not for the sake of air safety, that is obvious. If that was so, the report would have been much more accurate and the day-two story glorifying the AI commander would never have happened.

The ongoing investigation by Aircraft Accident Investigation Bureau will serve its purpose fully only if the answer to the above legitimate question too is found out.

(Jacob K Philip, a Doha based aviation analyst, is the honorary editor of Indian Aviation News Net. He can be reached at jacob@indianaviationnews.net)
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Written by admin

February 14th, 2018 at 4:37 pm

Posted in Safety