- 7 months ago
Chennai (TN), June 14, 2025 (ANI): Former Deputy Director of the National Aerospace Laboratories (NAL), Saligram J. Murlidhar, called the Ahmedabad plane crash one of the most unfortunate incidents in India's recent history, and raised the possibility of fuel contamination as a major factor behind the tragic incident.
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00:00A single engine failure is more or less ruled out.
00:04If you come to dual engine failure, that is very, very remote.
00:09And so far, we have not come across frequently that dual engine failure.
00:15Only in case of any bird hit, we get the dual engine failure.
00:20It cannot be due to bird strike.
00:23Because if it is due to bird strike,
00:25then you will get some sort of arcing, sparking and smoke.
00:31At the same time, both the engines will not encounter the bird strike at the same time.
00:37One of the reasons which can cause that sort of thrust loss, power loss,
00:45which prevented the aircraft from climbing,
00:49what I can think of is fuel contamination.
00:52Sir, what do you think about this Ahmadabad plane crash incident, sir?
00:57From your experience, what do you want to say to the public, sir?
01:00Sir, this Ahmadabad plane crash was one of the most unfortunate incident in Indian recent history.
01:11The previous crash, whatever we had, were different.
01:14This Ahmadabad crash, it is a Boeing Dreamliner.
01:19It is one of the most ultra-modern aircraft with all the safety, precaution, navigation.
01:24And it is almost foolproof.
01:27But still, something went wrong.
01:29And then it crashed.
01:31So, they are in the process of recovering the black box to get the actual information.
01:41It has got the CVR as well as the DFDR.
01:44And both of them are integrated.
01:47And they call it as a single unit in order to synchronize the data of CVR and FDR.
01:55Because it will give a better picture.
01:58Whatever event has occurred, it will reflect in the cockpit as well as in the FDR.
02:05So, we are in the process of getting the data.
02:07And looking at the wreckage, it looks like the aircraft is totally destroyed.
02:13And even the black box will undergo a very high temperature impact, whatever is there.
02:19But it is still shockproof, heatproof, whatever is there.
02:23The data that is in-house in a small container will be intact.
02:30So, the first thing what they have to do is to locate the FDR.
02:34They have to pull out the memory card from the FDR, mount it on a healthy unit, which can be replayed.
02:43And then you download the data to your computer to start your analysis.
02:47So, that is the first point.
02:49And then, similarly, you get the data from the CVR.
02:53And you try to synchronize those two to see what is the conservation which has taken place.
02:58And then you try to correlate the root cause of this crash.
03:05So, what are the major measures?
03:08Okay.
03:08What are the airline companies, sir, on avoiding this kind of incidence?
03:13Normally, when we investigate any accident, we follow a certain procedure.
03:22It is called as process of elimination.
03:27That is, we take a very big blackboard.
03:30And we try to write down all possible causes of the crash without leaving anything.
03:38Even if it is something unimaginable, we still take it.
03:41For example, if you say that there can be an alien abduction for MH370, we take it.
03:47Subsequently, we say that it is very remote, but we take everything.
03:51So, taking all the possible causes which can cause the crash, we write on a blackboard and then we start the process of eliminating one after the other, which are very unlikely.
04:06So, the crash can take place due to several reasons.
04:13It can be due to weather phenomena.
04:16So, you have, you are flying and suddenly you encounter some turbulence or severe thunderstorm or whatever it is.
04:25It can damage the aircraft.
04:27So, that is due to natural phenomena.
04:29Or you can have due to something called as a wind shear.
04:34There is a microburst when the packet of air comes down and hits the ground and it gets dispersed in all the direction.
04:44And particularly if it happens on the runway and at the time when the aircraft is landing,
04:51first the aircraft will encounter a head wind because of the downburst.
04:56And the aircraft will tend to pitch up.
05:00The pilot will try to correct the course of action by bringing it down.
05:04And once it passes through the center of the impact of a downburst, it becomes a tailwind.
05:10Then he is going to suddenly lose the speed and the aircraft will stall and crash.
05:16That is one of the weather-based phenomena.
05:19So, like that you have got other man-made disasters where things can go wrong either from pilot or maintenance engineer or whatever is there.
05:33So, that is man-made.
05:35Similarly, we have got many other reasons for the crash.
05:40So, the last one, what I would like to stress is sabotage.
05:46It is something very, very serious and it is difficult to predict.
05:53So, coming back to this Ahmedabad plane crash,
05:59whatever little bit of information we have seen on the TV, on the media,
06:05let us try to draw some inference before we get the actual data.
06:11The system shows that the aircraft climbed to a height of 625 feet before it started descending.
06:23So, if the aircraft is airborne, it means that things are somewhat okay.
06:34But, when you look at the rudder component of the aircraft, it looks very stable.
06:44When the aircraft reached 625 feet and it started descending,
06:48it looked as though it has lost its thrust or the power.
06:53Now, the power loss can be mainly due to loss of engine.
07:00If there is an engine failure, then obviously the thrust what is generated is reduced a lot.
07:07For engine failure, which is quite rare, it is not something common, but it is very, very rare.
07:15If there is an engine failure, then there is a large amount of thrust asymmetry,
07:21which will try to wear off the engine aircraft in the particular direction,
07:25which is compensated with your rudder.
07:28But, here we find that the rudder is almost a standstill.
07:33There is no movement of rudder.
07:34So, a single engine failure is more or less ruled out.
07:40Now, if you come to dual engine failure, that is very, very remote.
07:46And, so far we have not come across frequently that dual engine failure.
07:52Only in case of any bird hit, we get the dual engine failure.
07:57For example, in U.S., the aircraft, the A320, which landed in the river,
08:02it was mainly due to the dual engine failure of the bolt strike.
08:08Now, here let us see what could have happened.
08:11The runway of the Hamburg airport is 11,500 feet, which is really very long for any aircraft to take off.
08:26And, normally, when the aircraft takes off, it will lift off at something like half the runway
08:32or slightly at 60% of the runway length.
08:35If the aircraft had taken off and it was airborne at 7,000 feet,
08:43by the time it covers another 4,000 feet, it would have climbed a lot of distance.
08:49But, here it looks as though when the aircraft was crossing the boundary of the perimeter of the airport,
08:57it was hardly at 620 feet.
09:00It means the aircraft is unable to generate the required lift for climb.
09:08And, then we find that the landing gear is down.
09:12It is not retracted.
09:14The normal practice is the person who is monitoring the aircraft,
09:21he will give the call out.
09:22He will say 100 knots to alert the pilot.
09:25And, then you have got next V1, that is the decision speed.
09:28The pilot has to take the decision whether to continue with the takeoff or to reject before V1.
09:35And, then you have got the next speed as VR.
09:38It is called as a V-rotate.
09:40So, the pilot will rotate the aircraft and the aircraft is airborne.
09:43Subsequently, the first officer will say, positive climb, gear up.
09:49So, the gear is retracted when the aircraft reaches around 30, 35 feet.
09:54And, then you have got a speed called as a V2 speed.
09:57The aircraft should have climbed, should attend a speed of whatever is the V2 speed.
10:03By the time the aircraft climbs 35 feet,
10:05that will ensure that the aircraft is airborne and has got sufficient power and speed to climb
10:11and to continue even in case of an engine failure.
10:14But, here we find that the landing gear is down.
10:18It is not brought up.
10:19So, what could have been the reason for not bringing the landing gear up?
10:27There may be some problem with the thrust because the aircraft was not climbing.
10:33Now, if we look into the possibility of both the engines malfunctioning,
10:41which is very, very remote,
10:43it cannot be due to bird strike.
10:47Because, if it is due to bird strike,
10:49then you will get some sort of arcing, sparking and smoke.
10:54At the same time, both the engines will not encounter the bird strike at the same time.
11:01There will be a small time lag between the first engine failure and second engine failure.
11:07Meanwhile, the aircraft will try to veer off in one direction
11:11and you will find some rudder moment.
11:13But, here there was no rudder moment.
11:15So, it looks as though both the engines were behaving in a very same way,
11:24without any time difference, without any, there was no discrimination.
11:29So, one of the reasons which can cause that sort of a thrust loss, power loss,
11:38which prevented the aircraft from climbing,
11:40what I can think of is fuel contamination.
11:46That is one of my strong points for both the engines,
11:51stalling simultaneously and losing the power.
11:54Because, the same fuel goes to both the engines.
11:57So, if the fuel is contaminated,
11:59both the engines will behave in the same way
12:01and the thrust what is generated is less.
12:04The aircraft could not sustain the climb rate
12:08and then it could not even sustain the level flight.
12:12The aircraft descended and it fell
12:14because it contained more than 35 tons of fuel to reach London.
12:21It was like a fireball.
12:22The moment it crashed, there was a big, huge fireball
12:26and then there was a lot of smoke
12:27and the aircraft fell on a medical system,
12:34hostiles, what they call it as.
12:36And there were a lot of casualties on that.
12:38So, the most probable cause, what I feel,
12:41is due to fuel contamination.
12:45And the other things will be reflected
12:48once we get the data from DFDR
12:50and we get all the parameters
12:52about the thrust-generated RPM, fuel flow,
12:57how much of fuel is carried.
12:58Those parameters will show up,
13:01EGT, all the autopilot engaged,
13:05the command given to retract the,
13:07whatever command is given,
13:09that will reflect and also the CVR will tell
13:11the coordination between the captain and the first officer,
13:15how they acted and how they handled the situation.
13:17Can you please repeat the question?
13:23The main safety procedure,
13:25what has to be followed,
13:26is assigned to crew member,
13:29to pilot, to passenger.
13:31Everything is different.
13:33And then we cannot have a single guideline
13:36for all the cases.
13:39It is like giving medicine.
13:41So, when you take medicine,
13:43it depends on what is that element you have got.
13:47So, based on the ailment,
13:48you are going to get the medicine.
13:49So, every case is unique
13:53and it has to be looked deep into the process.
13:56We cannot have a general guideline.
14:00We can have certain minimum guidelines,
14:02but we cannot have a magic stick
14:07which will cure everything.
14:09So, it is for the management
14:11and for the other airport authority
14:13to implement whatever the safety regulations
14:16is based on the past experience.
14:19And every case is totally unique,
14:21totally different
14:22and every crash will give you some new lesson
14:26and it will give you something how to overcome.
14:29Just to take a very simple example,
14:33one of the Boeing 777 aircraft
14:36which long back almost 10 years back
14:39which was landing at Heathrow Airport.
14:43He was in the idle descent
14:45and he was the glide path.
14:47The final approach
14:49when he tried to correct his flight path
14:51by giving some power to the aircraft,
14:55the engine did not respond.
14:58Means there was a fuel starvation
15:01of the engine.
15:03Whatever power he is giving,
15:05absolutely it is like pressing a throttle
15:07and your car is not accelerating.
15:12So, that was the situation.
15:15And when they analyzed
15:17and when they decoded,
15:18they found that there was lot of froth formation
15:21in the fuel tube
15:23and when thrust was given
15:26that froth formed a ice layer
15:30in the heat exchanger
15:32and then it prevented the fuel flow
15:35and that resulted into a short landing.
15:41It landed much before the runway.
15:44The aircraft was slightly damaged.
15:46There was no fatality.
15:47But once they realized the problem,
15:50they immediately changed the heat exchanger
15:53of all the aircraft
15:55and they made it in the form of a straw
15:58with a different altitude,
16:00different height
16:01so that even if some of the heat exchanger
16:04hexagon holes are blocked,
16:08still you will have certain other holes
16:11from where the fuel can flow
16:12and it can heat up the engine.
16:15So, like that,
16:15based on the experience,
16:17every experience will give you,
16:20every accident will give you something new
16:22to improvise the system.
16:26So, it is not something unique.
16:28You cannot have a,
16:29if there is a mid-air explosion
16:32due to some electric spark
16:35in the fuel tank.
16:37There was a case
16:38when there was a fuel tank exploded
16:41because of some small transducer,
16:43electric spark.
16:44Then they said that
16:46we have to see to it
16:47that the air
16:50which is super saturated
16:51in the wing
16:52should be removed.
16:56So, what they did was
16:57they filled that one
16:58with nitrogen
16:59because nitrogen is an inert gas.
17:02So, even there is a small spark.
17:03It is not going to ignite
17:04just like your super saturated air.
17:07So, that gave a very good lesson for them.
17:10Similarly,
17:11Bangalore crash also gave
17:12a lot of information to them
17:14how to design the window,
17:18how to design the,
17:20how to keep,
17:20how much to keep the idle,
17:23this power 40% 60%,
17:25whatever,
17:25every accident will come out
17:28with some new ideas
17:30which helps them in
17:32improving the safety.
17:34But, if you are really
17:37very smart,
17:38then you should be able
17:39to predict certain
17:40false,
17:43there is a failure
17:44in advance
17:44and you should try to take
17:45a remedial action
17:46before it culminates
17:48into a crash.
17:49So, the expertise
17:50will tell you
17:51what are the,
17:52it is like
17:53an iceberg
17:55floating in a sea.
17:57What you see
17:57is the tip of the iceberg.
17:59That is the problem.
18:00But, there are
18:01a lot of other problems
18:02which is hidden
18:03inside the water
18:04which is not seen.
18:07So, only when you
18:08expose that
18:09iceberg
18:10by lowering the water,
18:12you will be able to
18:13indicate
18:14what are the problems
18:15and how to overcome.
18:16So, it is just
18:17evolution,
18:19continuously
18:20improvising.
18:22There is no beginning,
18:23there is no end.
18:24You have to continue
18:25to
18:25improvise the system.
18:27So,
18:29that's all.
18:30Every case
18:31is unique
18:31and you have to
18:32see to it
18:32that things are,
18:34the data
18:34of the previous
18:35crash or incident
18:37is made use of
18:38to improvise
18:39that it doesn't
18:40occur again.
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