Military Flight Safety

Indranil · Post by **Indranil** » 30 Apr 2011 01:26

putnanja wrote:IJT crashes during test flight

The debry field does look very concentrated. I feel the prototype was falling on its belly. Might have indeed entered a flat spin.

shiv · Post by **shiv** » 30 Apr 2011 05:48

indranilroy wrote:
putnanja wrote:IJT crashes during test flight

The debry field does look very concentrated. I feel the prototype was falling on its belly. Might have indeed entered a flat spin.

Good assessment of the photo IMO. That is the feeling I had but was unable to express it in the succinct language you have used.

PratikDas · Post by **PratikDas** » 30 Apr 2011 06:17

IMHO a 2D thrust-vectoring nozzle for yaw would really help.

saps · Post by **saps** » 30 Apr 2011 07:30

I guess the concept of flat spin would not arise in conventional control aircraft like IJT. But even though if it was in normal spin the debris would still be concentrated in very small dia...post impact.

Whats the take of gurus on this.. ?

Indranil · Post by **Indranil** » 30 Apr 2011 09:36

saps wrote:I guess the concept of flat spin would not arise in conventional control aircraft like IJT.

What do you mean?

saps wrote:But even though if it was in normal spin the debris would still be concentrated in very small dia...post impact.

Whats the take of gurus on this.. ?

You are right that a concentrated debry-field could have been from a nose dive. But generally you won't see the plane as a lump. As it goes nose first the pressure is much higher and it completely disintegrates the plane. you wouldn't have seen a lump of metal. Also if the plane is nosediving it would be a recoverable maneuver if there is enough height.

I didn't want to speculate. And we probably should all wait for the report. Sorry to have been impulsive.

saps · Post by **saps** » 30 Apr 2011 18:58

[quote]saps wrote:
I guess the concept of flat spin would not arise in conventional control aircraft like IJT.

What do you mean?
[/quote]

Well i meant that as far as my understanding goes....IJT cannot get to such AoA that when it enters spin it would get into a flat attitude. AFAIK the attitude in spin would be dependent on drag and that in turn would depend on the AoA at entry. So this logic defeats the idea of IJT flat spin.

Any corrections to the thought process, welcome.[quote][/quote]

shiv · Post by **shiv** » 30 Apr 2011 19:23

saps wrote:
Well i meant that as far as my understanding goes....IJT cannot get to such AoA that when it enters spin it would get into a flat attitude. AFAIK the attitude in spin would be dependent on drag and that in turn would depend on the AoA at entry. So this logic defeats the idea of IJT flat spin.

Any corrections to the thought process, welcome.

I am no expert - but I think there are situations in which any aircraft can get into a flat spin (I vaguely recall reading that/hearing that somewhere).

On the other hand there are aircraft that normally just don't get into a spin. An aircraft that does not spin is useless for training because training requires that the pilot experiences how it feels when he is in a spin (disorientated, eyeballs popping out, world spinning) and still do what is needed to recover, or bail out if that is not possible. The latter may mean full awareness of how much altitude he has and whether spin recovery is possible in the given altitude. All this requires training in an aircraft that can be put into a spin deliberately and is known to recover from such spins. Those characteristics can only be tested first in a spin testing center and later "live" by pilots. I will come to a conversation I had with Air Marshal Rajkumar (retd) about this later.

But first, "flat spin". As far as i know a flat spin is one in which the airflow over the aircraft is reversed. Not only does this make the plae's controls ineffective but it may flame out a jet engine. Once that happens there is no hope of recovery.

I had this very interesting conversation with AM Raj and he told me of a fascinating spin simulator that he has seen in France. Russia also has one. India does not have one currently. (Add this to the list of things that India needs to get apart from engine test platform - but for ideas about that read Prodyut Das's article that I posted in the design your own fighter thread)

In a spin simulator there is a fan that blows air up a tube. A model of the plane is dropped from the top of the tube in an attitude that gets it into a spin. As it falls in the tube, the fan blowing air up the tube has its speed adjusted so the plane remains spinning in the upward airflow of the tube but at the same altitude and can be filmed for spin characteristics.

This is only with models - but the final answer comes from test flying by test pilots. The Gripen has apparently been put through something over 200 different high AoA tests (which can result in a spin). The only sure way of recovering an aircraft from a spin if the usual maneuvers do not cause recovery is to use a spin chute which deploys and lifts the tail up and makes the plane go nose down so the proper direction of airflow is restored. That is why the LSP 6 of LCA will have a spin recovery chute.

Nothing is certain100% in the world of aircraft testing. An aircrfft can enter service and serve in the air force until one day a pilot does something that nobody has done before that results in an accident. if the pilot is lost nobody might find out the cause. But if he is saved and there is a data recorder - the exact circumstances that caused a "reliable and in service" plane to go down will be discovered and will be written on the database of that aircraft as an extra titbit of aerodynamics gyan.

Any errors are mine and hopefully some real aviators will clarify any mistakes.

Indranil · Post by **Indranil** » 30 Apr 2011 20:20

saps wrote: Well i meant that as far as my understanding goes....IJT cannot get to such AoA that when it enters spin it would get into a flat attitude. AFAIK the attitude in spin would be dependent on drag and that in turn would depend on the AoA at entry. So this logic defeats the idea of IJT flat spin.

Any corrections to the thought process, welcome.

Flat spin is not about AoA. It is about stalling and yawing. In a spin, both wings are stalled, one is stalled more deeply. this generally happens if there is yaw command just as the plane is entering the stall. So if your plane can go beyond the critical AoA of the wings, then you can certainly enter spin. Once in a spin, your ability to bring the nose down so that you can bring the wings below critical AoA would determine whether you can recover from the spin or not.

If you meant the AOA for the NASA "Spin Mode Classification", which classifies that AoA must be 65 to 90 degrees, you must realize that in a perfect spin, the plane has no lateral velocity. The only airflow direction is from the bottom of the plane, therefore for 90 degree AoA your plane must be horizontal. This is why it is called a 'flat' spin, because the plane is falling almost flat to nose down of 25 degrees.

Forget about IJT, even a farmers crop duster plane can enter a flat spin.

In this video you can see the recovery. at exactly 0:41 seconds you can see a shudder. The instructor explains in the comments that it is the point where the airflow re-attaches with the wing (the wings go below critical AoA) and remember here the airflow is from bottom to up so if the critical angle is 25 degrees, the plane should be going nose down at almost 65 degrees to recover.
[youtube]EJp6WAEVlwY&feature=related[/youtube]

Rahul M · Post by **Rahul M** » 01 May 2011 00:21

discussion on pawan hans moved to civil aviation safety thread. http://forums.bharat-rakshak.com/viewto ... 0#p1079570

Pragadeesh · Post by **Pragadeesh** » 13 May 2011 19:05

News Flash:

* IAF chopper crashes in Rajasthan, four killed*

Source: http://www.thehindu.com/ (News flash)
http://ibnlive.in.com/news/4-killed-in- ... 242-3.html

Unbelievable period of crashes.

May they rest in peace in God's abode.

Gaur · Post by **Gaur** » 13 May 2011 20:21

^^
As per your CNN-IBN link:

A Pawan Hans helicopter of the Border Security Force crashed in Sirohi district of Rajasthan on Friday killing the pilot and three others.

So, not an IAF chopper.
Its sad that 4 BSF soldiers died. RIP.

Rakesh · Post by **Rakesh** » 13 May 2011 21:52

What is up with Pawan Hans lately? A number of crashes.

sum · Post by **sum** » 13 May 2011 21:53

Gaur wrote:^^
As per your CNN-IBN link:
A Pawan Hans helicopter of the Border Security Force crashed in Sirohi district of Rajasthan on Friday killing the pilot and three others.

Weren't Pawan Hans flights stopped till further notice after AP CM chopper crash?

Marut · Post by **Marut** » 13 May 2011 22:12

^ Pawan Hans flights in NE were stopped till further notice pending inspection & certification of helo conditions.

Rahul M · Post by **Rahul M** » 13 May 2011 22:18

it's probably a BSF helo.

Pragadeesh · Post by **Pragadeesh** » 13 May 2011 22:38

http://www.ddinews.gov.in/National/Nati ... copter.htm

Yes, they are BSF soldiers but still the chopper details is not clear.
I think the picture embedded in the news article heading is wrong.
The Pawan Hans website has no news about this incident http://www.pawanhans.co.in/site/aviation_news.aspx there is a possibility that this is not a Pawan Hans operated chopper.

shiv · Post by **shiv** » 04 Jun 2011 09:08

Cross post

karan_mc wrote:IAF launches indigenous software to predict aircraft accidents

Abhibhushan · Post by **Abhibhushan** » 04 Jun 2011 22:45

An old tale about destroying an aircraft on the ground

shiv · Post by **shiv** » 05 Jun 2011 06:11

Abhibhushan wrote:An old tale about destroying an aircraft on the ground

That is a brilliant story. It takes a great deal of courage to admit one's mistakes to the public and great erudition to explain complexity so a lay person can understand it.

Nikhil T · Post by **Nikhil T** » 02 Aug 2011 12:25

Just saw this flash

MIG-21 fighter plane crashes near Naal area in Rajasthan's Bikaner district

EDIT: Livefist reports that the pilot was killed. RIP brave soul.

Indranil · Post by **Indranil** » 02 Aug 2011 20:14

Rest in peace brother

Manish_P · Post by **Manish_P** » 03 Aug 2011 20:26

As per DNA the pilot was 24 years old Flying Officer Suraj Pillai from Kerala.

Dmurphy · Post by **Dmurphy** » 04 Aug 2011 15:10

Jaguar fighter aircraft crashes, two killed

http://www.thehindu.com/news/national/a ... 321766.ece

Two aircrafts in 3 days. Now wait for TOI to carry a front page article on "What ails the IAF?" and how unprofessional they are at maintaining aircrafts with comparisons drawn to US, Pak and China.

saje · Post by **saje** » 04 Aug 2011 16:33

Dmurphy wrote:Now wait for TOI to carry a front page article on "What ails the IAF?" and how unprofessional they are at maintaining aircrafts with comparisons drawn to US, Pak and China.

I hope they do and why not, that's the least that can be done isn't it? If we just say "RIP brave soul", "So long courageous brother" and leave it at that, these crashes will continue... as they have. The only way things are going to improve is when questions are raised, issues debated and people made accountable publicly. People have been hiding behind the veil of 'National Security' and 'red tape' for too long. Let BR members of the respective cities have a signature campaign and let's go hold a demonstration outside an airbase. We need to make the concerned people know that (like a phrase in Malayalam) there are people to question and talk... or another mother will soon get a box full of burnt flesh and a photo on the wall and people will just type sympathies on a blog and forget about it... till the next crash.

chackojoseph · Post by **chackojoseph** » 04 Aug 2011 17:11

Photos: Cremation of Flying Officer Suraj Pillai

Gurinder P · Post by **Gurinder P** » 04 Aug 2011 17:18

saje wrote:
Dmurphy wrote:Now wait for TOI to carry a front page article on "What ails the IAF?" and how unprofessional they are at maintaining aircrafts with comparisons drawn to US, Pak and China.
I hope they do and why not, that's the least that can be done isn't it? If we just say "RIP brave soul", "So long courageous brother" and leave it at that, these crashes will continue... as they have. The only way things are going to improve is when questions are raised, issues debated and people made accountable publicly. People have been hiding behind the veil of 'National Security' and 'red tape' for too long. Let BR members of the respective cities have a signature campaign and let's go hold a demonstration outside an airbase. We need to make the concerned people know that (like a phrase in Malayalam) there are people to question and talk... or another mother will soon get a box full of burnt flesh and a photo on the wall and people will just type sympathies on a blog and forget about it... till the next crash.

Dude, I have to say this, but I mean no disrespect. The 21's are really old, so olde that I put an 'e' after old. I don't think spares are even made for the versions before the Bison upgrade. Sadly, these aircraft are the mainstay of the IAF and it has to remain that way until the MMRCA winner comes online and the Tejas hit the production line. Have faith in the mechanics and the standards of the IAF, they are doing the best they can with what they have. Here in Canada, our Sea Kings are being held together with Duct Tape, its that bad.

My prayers to the fallen air warriors. May they have a glorious feast alongside the Gods in Valhalla.

Shameek · Post by **Shameek** » 04 Aug 2011 17:29

saje wrote:I hope they do and why not, that's the least that can be done isn't it? If we just say "RIP brave soul", "So long courageous brother" and leave it at that, these crashes will continue... as they have....

We at BR don't say 'RIP Brave Soul' for the heck of it. It pains each one of us to lose a courageous warrior, whether it is in peace or war. Do you hear the papers say that? The thing we don't like is not about crashes being reported or making safety important. It has more to do with papers ranting and frothing at the mouth with misguided and factually incorrect articles everytime an aircraft goes down. It may be something like a pic of an LCA in a MiG 21 crash or something on the lines of 'There have been so many crashes...', a random statement that seems to indicate planes are dropping like flies.

The common man who reads this accepts it as the truth and this damages the image of the Air Force. For a person not versed with IAF details, DDM saying we are worse than US, Pak and China becomes a fact of life which he then goes and mentions to friends and relatives. That spreads epithets like 'flying coffin' and makes people not want to see their loved ones in the Air Force. Everytime there is a train accident, do you compare all train accidents since the Indian Railway was born? I dont think so. But everytime there is a crash, people suddenly want to go back to 1960 and count every MiG 21. What does this prove?

Sandipan · Post by **Sandipan** » 04 Aug 2011 19:02

^^^^^

I don't agree with the earlier post as to having issues with Media for criticizing IAF for crashes. It is granted that IAF is doing best it could do with old planes and trying to keep them air-worthy. It is granted that Defence reporters don't always have their facts correct and try to generalize specific events. But, this is a democracy. People are supreme, any institution whether IAF, Media etc are subservient to people. So, public criticism even if excessive sometimes is must to keep the institutions healthy and responsive. IAF or any institutions whose sole moto is serve the people of India is not beyond the criticism of people.
We can argue about stupidity of an individual journalist but getting touchy at a mere hint of criticism of defence forces is unwarranted.

shiv · Post by **shiv** » 04 Aug 2011 19:13

Dmurphy wrote:Jaguar fighter aircraft crashes, two killed

http://www.thehindu.com/news/national/a ... 321766.ece
.

This is really weird. Aircraft crashes 50 km from the air base. That means it was up and flying alright. Wonder what went wrong - although the satellite pics of India show monsoon clouds all over so weather and disorientation are possible esp if there was some sort of exercise/training session in blind flying with simulated instrument failure or something going on.

sanjeevpunj · Post by **sanjeevpunj** » 04 Aug 2011 19:48

Lives of Pilots and civillians are lost in such events.Whatever explanations are given later, lives are invariably lost.Everyone wonders what went wrong, and each time,it is obvious something unexpectedly went wrong, because efforts are always on to correct past mistakes.Reporting such events must always be very cold and factual.In response,the onus is always on the govt, to compensate the losses monetarily, and the least the IAF sources can do is issue a genuine condolence message through the press.That always takes care of ruffled feathers in the public.At the same time,internally within IAF,I am sure the process of enquiry always goes on, to prevent future crashes. This was a rare Jaguar crash though.

jimmy_moh · Post by **jimmy_moh** » 04 Aug 2011 20:11

^^ yes this was rare jaguar crash... but happened in a bad time just after mig-21s crash

Pratik_S · Post by **Pratik_S** » 04 Aug 2011 20:23

Indian Air Force has lost 999 planes in crashes since 1970

ramana · Post by **ramana** » 04 Aug 2011 20:36

Could the Jag crash be due to fatigue or sabotage?

manum · Post by **manum** » 04 Aug 2011 21:04

sorry to hear the loss...RIP brother, may family gather the strength to cope up.

shiv · Post by **shiv** » 04 Aug 2011 21:15

ramana wrote:Could the Jag crash be due to fatigue or sabotage?

Judging from past experience it will be pilot related issues or maintenance/overhaul issues.

putnanja · Post by **putnanja** » 04 Aug 2011 21:32

Sad indeed!

RIP both the pilot and the girl!

Do we know if this was one of the recent builds of Jaguar, or a older one?

Shameek · Post by **Shameek** » 04 Aug 2011 21:52

Sandipan wrote:We can argue about stupidity of an individual journalist but getting touchy at a mere hint of criticism of defence forces is unwarranted.

No one is getting touchy here and what our papers write is not a 'hint' of criticism. This is not the first time this has happened and won't be the last time. And yes, you are welcome to disagree with my post. I'll end it at that.

sanjeevpunj · Post by **sanjeevpunj** » 05 Aug 2011 08:49

Finally the press catches up and starts pointing at lack of trainers.Is that so?

Lack of trainers takes toll on young pilots.Published: Friday, Aug 5, 2011, 8:30 IST
A Jaguar fighter aircraft of the Indian Air Force (IAF) crashed on Thursday in UP’s Gorakhpur, killing the pilot, Flight Lieutenant S Pandey, and a farmer.
Pandey was on a training sortie when the aircraft spun out of control and crashed killing a farmer on the ground and then sunk into a nearby pond.
This was the second major accident for the IAF in a week. Flight Lieutenant MS Pillai died in a training sortie while flying a MiG 21 in Nal, Bikaner, on Tuesday.
Sources in the IAF headquarters told DNA that evidence available in both accidents pointed to a case of pilot error.
“It is too early for us to draw any conclusions but in both cases, these were young pilots with about 40 hours of flying behind them,” a senior air force official said.
According to him, the Jaguar pilot was flying at a low level and had completed a series of maneuvers when he suddenly did a hard turn and the aircraft spun out of control.
“We are still trying to locate the FDR (data recorder) of the aircraft, which will have all the details, but we are guessing that the pilot lost control.”
The MiG-21 crash also occurred in similar circumstances when the pilot was on a low-level flight and suddenly lost control and crashed into the ground.
The initial investigations have revealed that there was no defect in the upgraded MiG-21 “Bison” thus narrowing down the cause of the accident to “pilot error”.
Both crashes come within days of the induction of the new chief of air staff, Air Chief Marshal NAK Browne who is a Jaguar pilot.
Sources close to Browne told DNA that the air chief was extremely disturbed and was looking at training schedules of the rookie pilots to prevent such accidents.

Source:http://www.dnaindia.com/india/report_la ... ts_1572745

rohitvats · Post by **rohitvats** » 05 Aug 2011 13:18

From Livefist:

IAF trainee pilot Flt Lt S Pandey, who tragically perished in a Jaguar ground attack aircraft crash yesterday, was on a low-level navigation syllabus sortie from the Gorakhpur Air Force Station, and was accompanied by a senior pilot in chase in another Jaguar. Flt Lt Pandey had been on a simulated attack run at ultra low level (below 300 feet to avoid radar) from initial point to target, completed in roughly 2.5 minutes. However, the pilot missed his target, the reasons for which will be part of the court of inquiry. His chase instructor radioed in asking him to turn back and redo the attack manoeuver.

Now the normal drill during such training is to pull up to at least 500 feet, turn around, descend at your initial point and go back for the sim attack. Tragically, for reasons still unknown, Flt Lt Pandey began turning around at less than 300 feet, bleeding altitude all the while. The investigation will look into several human and technical factors. Of the latter, the possibilities include an inexplicable breakdown of the entire (or parts of the) flight control system, including the auto-stabilizer system or pitch trim controller, both overwhelmingly critical at such low altitude where reaction time is wafer thin.

sanjeevpunj · Post by **sanjeevpunj** » 05 Aug 2011 15:10

^^^More indication towards pilot error.