Military Flight Safety

[ramana]

Veey good analysis by Rohit Vats of the AN 32 incident.


https://twitter.com/KesariDhwaj/status/ ... 17696?s=19

[MeshaVishwas]

#IAF has intensified efforts to locate the missing AN-32. Despite challenges posed by vegetation, inhospitable terrain & poor weather,the search has been expanded.All leads from airborne sensors are being closely assessed and followed-up with search by aircraft & ground teams 1/2

https://twitter.com/IAF_MCC/status/1136 ... 59136?s=19

Search by IAF and Indian Army helicopters was adversely affected by weather during the day today. However, supported by #IndianArmy, #IndianNavy, Police and State Administration the search efforts by ground teams and airborne sensors will continue through the night. 2/2

[Mahesh_R]

Search Operation For Missing IAF AN-32 Continues For 5th Day Amid Adverse Weather
https://www.india.com/news/india/search ... r-3681936/


Any updates ? I get so worried about the families just thinking what they may be going through.. although our forces might be doing everything possible but there is no follow-up any where in the news ... so worried.. any news..updates.. not sure it would take 5 days to complete the search on land with so many resources at their disposal...

[ramana]

I have been thinking about the M2K pitch oscillations due to the flight computer commanding the pitch down violently.
And its rare occurrence.
We know that in the M2K upgrade program, the Dassault OEM FC black box is not touched by HAL.

Do we know the age of the FC black box and its mfg history?

An incident recorded in 1989 recounts that Mirage 2000, aircraft number KF138, experienced “sudden and momentary pitch oscillations... (for) a few seconds” at an altitude of 4,500 feet some 16 minutes after take-off. The oscillations exerted a violent force of “+10.5g to -6g” (“g” indicates the force of gravity) on the pilots and caused the cockpit’s red and amber warning lights to glow.

Similarly, in 1999, Mirage 2000, aircraft number C98, “experienced momentary pitch oscillations… (for) a few seconds at 10,500 feet altitude, exerting a force of 11g on the aircraft and pilots. Exerted over a few more seconds, 11g force would cause most pilots to black out.

In 2014, Mirage 2000 number KF118, about 20 minutes after take off, at about 11,500 feet, experienced “amber failure warning light and sudden pitch oscillations… (for) a few seconds.”

In all three cases, the altitude allowed the aircraft time to recover itself.

Even luckier was another Mirage 2000 pilot who, as recently as February, experienced similar spontaneous commands from his flight computer while his fighter was taxiing out to the take off point, and was still on the ground.

Those earlier incidents, which the IAF investigated through internal inquiries, were never conclusively explained. Dassault, which supplies the flight computer, offered the explanation that the aircrafts’ “pitch rate gyrometers” — sensors that tell the flight computer the aircraft’s attitude – were not securely fitted. But neither the IAF, nor HAL, is convinced, since the Mirage 2000s behaved perfectly for the rest of the flight when the incidents occurred.

Reason is there is a possibility of tin whiskers (from the solder) growth in the circuit cards with time.
Tin whiskers grow due to residual stress in the solder as it shrinks.
Takes years to grow.

The tin whisker could cause intermittent short and cause the pitch down command.
The sudden onset and violent pitch down would dislodge the tin whisker.
And normal operations resume.
Unless the box is put on shake table will not reproduce the fault.

Of the four previous incidents, how was the plane flying before the incident?
If it was maneuvering then this scenario could have happened.
We know the crash FC was quite old.

[Indranil]

Redundancy should have taken care of it. Most likely, it is a very rare flight condition not captured in the algorithm.

[Luxtor]

In cases of our aircraft going missing like this An-32 in the north-east and the one flying from Chennai to the Andamans a while back, I think IAF should implement some sort of real time flight monitoring of all of their aircraft at the IAF headquarters in Delhi. So we'll know immediately and the exact point where it went missing. I think with our fleet of satellites and our technological capabilities we should be able to do this. It is far better than trying to find a needle in a haystack in topographies like these. I'm also concerned that the Chinese maybe doing something as one of our MKI's also went missing mysteriously in the north-east a little while back. Was that MKI ever found?

Sorry if this idea has been posted already by a fellow member.

[chetak]

I have been thinking about the M2K pitch oscillations due to the flight computer commanding the pitch down violently.
And its rare occurrence.
We know that in the M2K upgrade program, the Dassault OEM FC black box is not touched by HAL.

Do we know the age of the FC black box and its mfg history?

there is always a very detailed history of such a component/LRU available right from the days of the assembly of such a unit, including the names of the personnel who worked on it, its mod status, its test procedures, and test results, records of any failure analysis during an unscheduled shop visit and what, if any, parts were replaced, when replaced and by whom, and for what reason and who tested it, who cleared the test results and who certified the unit as "serviceable", where it was stored, under what conditions and when it was issued for use, who tested it prior to use and what were the results of such tests.

On installation, it again undergoes system tests and it will not be accepted unless it passes set criteria.

these are standard processes used for any aircraft LRUs, no matter whether civil or military.

[chetak]

Redundancy should have taken care of it. Most likely, it is a very rare flight condition not captured in the algorithm.

sirji,

why did they not carry out a proper and detailed investigation by the designers/manufacturers, after all there seems to have been a series of such "unexplained" glitches. Did they not resolve the issue by getting down to the root causes

after the third such incidence, it is extremely foolish to simply write it off to "a very rare flight condition not captured in the algorithm."

at the prices you are paying, no such algorithms should be written or in a worst case scenario, left unresolved.

did they have any business writing such an algorithm and unleashing it on the unsuspecting piloting population without adequate testing both in the lab and in flight. After many incidents, they very well knew that the glitch was balefully lurking in the background and posed an unacceptably grave risk to the success of any combat mission undertaken by this aircraft.

wasn't it just such a shortcut imbecility, almost similar management techniques and a generally pervading couldn't care less mentality that led to the self created disaster of the Boeing 737Max

[Bhaskar_T]

"BREAKING: GoaAirport closed temporarily for a few hours view incident of fire caused by a drop tank of MiG 29K which got detached whilst taking off. All efforts in hand to resume flights ASAP. MiG 29K fighter aircraft is safe." - Indian Navy Official Twitter Handle. Large plumes can be seen as well in pictures.

https://twitter.com/indiannavy/status/1 ... 90529?s=19

[Mahesh_R]

https://timesofindia.indiatimes.com/ind ... 706210.cms

IAF announces Rs 5 lakh for any information

Extensive aerial search operation entered the sixth day on Saturday without any breakthrough so far......The area of search is mountainous and heavily forested with thick undergrowth. The weather in the area has been inclement with low clouds and rain during most hours. Combined with the inhospitable terrain, the weather has posed serious challenges to aerial search operations....

[tsarkar]

I think IAF should implement some sort of real time flight monitoring of all of their aircraft at the IAF headquarters in Delhi.

Transponders fulfill this function. This year (or was it last) IAF released a detailed video of radar plot of precise coordination among multiple aircraft with varying speeds and altitudes practising for Republic Day parade.

However weather and terrain degrade equipment performance.

[tsarkar]

Chetak and Indranil - there was a point of time when the British would tropicalise their ships and aircraft by thorough testing in ME, India, Asia & Africa. With corporatizations, corners are cut. Atmospheric conditions in tropical countries like India are very different than Europe. It’s not a fluke that both MAX accidents happened in tropical regions. Due to temperature fluctuations atmospheric conditions change abruptly and if sensors and flight control systems are not tuned accordingly, then it’s only a matter of time before disaster strikes.

[Indranil]

Chetakji,

Why are you angry on me?

I am with you on this. That Ajai Shukla article is too specific to be without merit. He couldn't have cooked that up. So, IAF and HAL have flagged this before. Dassault kept brushing it aside. While it is not that uncommon, this is far from ideal. Two men have paid the price.

The other part of the mystery is why couldn't arrester barrier do its job? HAL and the private company who delivered that product are answerable for that.

The two TPs tried to save the aircraft, banking on the barrier to work. How I wish they didn't. I care two hoots for that damn aircraft.

[Luxtor]

I think IAF should implement some sort of real time flight monitoring of all of their aircraft at the IAF headquarters in Delhi.

Transponders fulfill this function. This year (or was it last) IAF released a detailed video of radar plot of precise coordination among multiple aircraft with varying speeds and altitudes practising for Republic Day parade.

However weather and terrain degrade equipment performance.

Transponders work only within radar coverage.

[chetak]

Chetakji,

Why are you angry on me?

I am with you on this. That Ajai Shukla article is too specific to be without merit. He couldn't have cooked that up. So, IAF and HAL have flagged this before. Dassault kept brushing it aside. While it is not that uncommon, this is far from ideal. Two men have paid the price.

The other part of the mystery is why couldn't arrester barrier do its job? HAL and the private company who delivered that product are answerable for that.

The two TPs tried to save the aircraft, banking on the barrier to work. How I wish they didn't. I care two hoots for that damn aircraft.

no one is angry with you, saar.

The hitjob should have rightly been on Dassault but instead, we see spin and obfuscation, muddying of waters and quoting of articles by presstitutes who are being paid off. All these favor the frenchies and not so subtly, also downgrade the capabilities of the natives.

Is the arrester barrier really meant to do the job that people are asking it to do. The barrier would its own limitations too, no

There was far too much energy in the aircraft when it engaged the barrier. It had already rotated and thereafter it came down again. The burners may have been engaged for the T/O roll. There would have been insufficient time for the energy to bleed out significantly. The brakes were possibly ineffective after the U/C was damaged, as reported.

No barrier built by the lowest quotation in the tender and CERTIFIED as acceptable by the powers that be and we all well know who they are, is going to behave in any other way.

Specifically, for the failure of the barrier, I would focus elsewhere and hang each of the SOBs from the nearest lamp post.

But first, I would minutely study the specs given to the contractor who built the barrier, and the acceptance test procedures specified to certify the same.

[chetak]

The other part of the mystery is why couldn't arrester barrier do its job? HAL and the private company who delivered that product are answerable for that.

The two TPs tried to save the aircraft, banking on the barrier to work. How I wish they didn't. I care two hoots for that damn aircraft.

I have a sneaky suspicion that many other "bade tope" agencies apart from HAL would be involved in the barrier saga and they are all keeping very quiet now.


primary among these would be the guys who actually approved the acceptance test procedures as well as the initial specs.

[chetak]

Chetak and Indranil - there was a point of time when the British would tropicalise their ships and aircraft by thorough testing in ME, India, Asia & Africa. With corporatizations, corners are cut. Atmospheric conditions in tropical countries like India are very different than Europe. It’s not a fluke that both MAX accidents happened in tropical regions. Due to temperature fluctuations atmospheric conditions change abruptly and if sensors and flight control systems are not tuned accordingly, then it’s only a matter of time before disaster strikes.

tsarkar ji,

environmental testing, these days, is mostly done in very high tech labs with some confirmatory tests actually done on the field.

Hot and high performance tests are confirmed in actual field conditions and operators lay more faith on these actual tests rather than on some bone dry lab condition synthetic testing.

Both the crashes of the MAX was with pilots who had no clue about the modified system and hence did not react with the hindsight of possible solutions. They fatally spent precious time in analyzing the situation and all this happened at low level flight which made the situation virtually unrecoverable. They were overwhelmed by the system and they had no clue that such a system even existed. They were no less of a victim than their passengers.

If the pilots and a majority of the passengers were white, trust me, the reactions world wide would have been very very different.

what boeing and the FAA are guilty of is primarily technical racism covered up in a lot of specious double talk and gobbledegook.

The MAX AOA sensors would not have been cleared without undertaking and clearing a full range of environmental tests in all applicable conditions.

What is beyond the scope of both design as well as manufacturing is that fact of the actual handling of these sensors in the field by the airline logistics/technical staff and how engineering, maintenance, and storage standards are enforced by the concerned airline.

you may like to check this out


http://www.diva-portal.se/smash/get/div ... TEXT01.pdf

[Singha]

imo with no mayday call received, the possible theories could be

- it somehow flew across the border and crashed there in a remote area . the eastern tibetan and yunnanese people live there. its sparsely populated but there are ancient villages with stone watchtowers there.
- suddenly flew into a hill in whiteout conditions in controlled flight (I doubt the an32 has GCAS and TCAS like commercial planes do?) - knowing the route, this is unlikely as they would have climbed to a height to clear all hills. this was a routine high level ferry mission not a nap of earth SF raid.
- some fault in angle of attack sensor and artificial horizon in whiteout condition led to a sudden violent stall and dive
- catatrophic structural failure and plane disintegrated in seconds

my guess is #4

imo its best to ground the non-upg part of the an32 fleet for a week and ensure structural xrays and equip each one with atleast a portable SARBE beacon if the old fixed ones do not work. also its best to install more and more ATC radars on vulnerable routes in such areas and keep things constantly under a low grade surveillance . INMARSAT beacons can be installed which will perdiocially ping the sats. some of the mighty sinooks we purchased at great cost can be tasked to airlift diesel for the generator. need not operate 24x7, but just the early morning to afternoon hours when weather is clear for flying and planes are enroute.

far too long 70 years after independence there is no ATC radar, no weather radar and no cellphone connectivity in arunachal tracts yet we expect daily flights in hostile weather to work. time to use all the resources to fix this on the ground. same for flights over the hostile zanskar himalaya from down south to Leh, thoise and demchok and the karakorum to daulat beg oldie. weather systems around karakorum range make it a graveyard of mountaineers. its way more unstable weather and hostile terrain than the eastern himalayan cluster around everest. another feared place is the nanda devi region where 8 mountaineers perished recently. the most dangerous ones in nepal are annapurna and dhaulagiri.

[Singha]

i did some basic math on 2 engine turboprop ops between chennai and port blair where the other never found an32 vanished.

ATR72 has 120 min ETOPS rating:
The European Aviation Safety Agency (EASA) has just granted ATR, the European manufacturer of turboprop aircraft, “ETOPS 120 minutes” certification of its new ‘-600’ series ATR aircraft. This ETOPS (Extended-range Twin-engine Performance Standards) certification means that the ATR 42-600 and ATR 72-600 versions can now fly with one engine, as far as 120 flight minutes from any airport at which they can land. “ETOPS 120” thus allows aircraft to provide direct links between airports located at maximum distances equaling four flight hours (two hours maximum flight time from the departure airport plus two hours maximum flight time to the closest airport where to land safely).

its cruise speed is around 400kmph. distance madras to port blair is 1400km. so indeed a ATR72 is cleared to fly on this route - barely with 100km of leeway at each end if caught with 1 engine down in the middle. this is not accounting for headwinds and reduced engine perf in a emergency to keep it cooler.
however it does have western engines from pratt n whitney.

An32 cruises at a faster speed of 470kmph and has a range of 2500km. it was never registered with the west as a civilian airliner so has no formal etops certification. its ivchenko engines are 80s design but seem fairly reliable. what it needs is state of art survival beacon, GCAS, TCAS and enhanced from ground ATC radar monitoring, own transponders on vulnerable sea and mountain routes. we need to invest in saving lives, not valiant post crash recovery missions and list of high tech assets being used.

[Singha]

are barriers designed to stop a/c that have reached takeoff speed ? I wuz thinking they are more like to catch ac that overshoot due to rains, failed brakes and landing beyond the usual wheels down point at a much lower landing speed(this can happen when another heavy has landed just before and pilot wants to avoid its dropping vortices so lands ahead....reverse is case for takeoff, they rotate earlier).

[chetak]

are barriers designed to stop a/c that have reached takeoff speed ? I wuz thinking they are more like to catch ac that overshoot due to rains, failed brakes and landing beyond the usual wheels down point at a much lower landing speed(this can happen when another heavy has landed just before and pilot wants to avoid its dropping vortices so lands ahead....reverse is case for takeoff, they rotate earlier).

precisely, saar.

blaming the barrier is counterproductive.

barriers are meant for aircraft with rapidly bleeding energy and not nearly enough overshoot area left. They are usually preceded by some sort of soft soil approach area that will further help to rapidly slow down the approaching aircraft by bogging down the wheels.

In the specific instance, they had rotated and the ONLY option left was to take off but fate intervened.

had they wilfully aborted at this stage, the endgame would have been eerily similar.

same to same, frame to frame.

[vcsekhar]

I have been thinking about the M2K pitch oscillations due to the flight computer commanding the pitch down violently.

Reason is there is a possibility of tin whiskers (from the solder) growth in the circuit cards with time.
Tin whiskers grow due to residual stress in the solder as it shrinks.
Takes years to grow.

The tin whisker could cause intermittent short and cause the pitch down command.
The sudden onset and violent pitch down would dislodge the tin whisker.
And normal operations resume.
Unless the box is put on shake table will not reproduce the fault.

Of the four previous incidents, how was the plane flying before the incident?
If it was maneuvering then this scenario could have happened.
We know the crash FC was quite old.

This is an interesting hypothesis on the failure of the FC computer.
But, IMHO while this is possible in theory, this is not practical. Tin whisker formation generally happens only in Pure tin plated parts, even now military electronics use only Tin/Lead plated parts and not RoHS pure tin plating.
This is also precisely the reason why the Rohs rules specifically allow tin/lead alloys to be used even in high density server mother boards.
Considering that the M2K FCC would have been made in the 80's when the RoHS rules were not in place, the boards would have been made with Sn/Pb solder, which is very resistant to tin whisker formation.
In fact, most MIL style connectors will typically use gold plated contacts to avoid issues of contact oxidation and corrosion.
I know a little bit about this as I work in a company making electronic components and we did a fair amount of work when moving to a lead free process many years ago to comply with RoHS standards.
Cheers.. hope this helps and thanks for all the discussions on the technical aspects, which i enjoy reading.

[chetak]

the vultures and urban naxals are gathering.



https://theprint.in/defence/computer-fa ... at/247927/

Computer failure or HAL’s botched upgrade — what Mirage 2000 crash probe is looking at

Court of Inquiry is still in process of pin-pointing exact cause of crash that killed 2 pilots. Difference of opinion among team members and stakeholders.

SNEHESH ALEX PHILIP, 10 June, 2019.


New Delhi: The probe into the fatal 1 February Mirage 2000 crash in Bengaluru is focusing on the possibility of either a computer failure or a botched upgrade by state-run Hindustan Aeronautics Ltd having led to the incident.

Two Indian Air Force (IAF) pilots testing the upgraded Mirage 2000, Squadron Leader Samir Abrol and Squadron Leader Siddhartha Negi, were killed in the crash at the HAL airport in the Karnataka capital.

Top sources in the defence establishment said the court of inquiry (CoI), headed by an Air Commodore who is an experienced Mirage 2000 pilot and a former Air Attache in France, is still in the process of pin-pointing the exact cause of the crash.

There is difference of opinion among the team members and the stakeholders, said the sources.

Computer failure or unfitted screws?
Sources said French aeronautics firm Safran made computer controls for the aircraft and it is suspected that the pitch rate gyrometers — the sensors that calculate the aircraft’s altitude — sent a wrong input.

Fighters like the Mirage 2000 are programmed to accept commands from the flight computer to keep the aircraft stable. Flight computers also play a role in release of the missiles or bombs on board in conflict.

“The CoI is now looking at what caused this wrong input. Was it a software problem or was it because three out of the four necessary screws on the sensors were not fitted,” a source in know of the CoI proceedings said.

HAL is carrying out an upgrade of the Mirage 2000 fighters, manufactured by the French firm Dassault.

Sources said the French firm had sought the sensors to be handed over for analysis but HAL refused to do so.

Arrester barrier failure
ThePrint had reported on 20 March that the CoI found that the crash was caused by an “uninitiated control input” — or a software glitch — during the jet’s user acceptance trial.

It established that the aircraft was about five metres from the ground, its nose pitched sharply down when the fully loaded fighter jet hit the runway on its main wheels and tail.

The CoI also ruled out any human error and found that the arrester barrier at the runway failed, eventually leading to the death of the two pilots.

The arrester barrier is a net with two hydraulic jacks that is installed at the end of runways to ensure an aircraft does not overshoot it.

The IAF continues to fly the upgraded Mirage aircraft despite the CoI looking into a possible software glitch.

[JayS]

https://www.drdo.gov.in/drdo/pub/techfo ... restor.htm

ARRESTOR BARRIER SYSTEM

Arrester barrier is a system installed at the end of the runway to stop the forward movement of an aircraft overshooting the runway, in case of a rejected take off or emergency landing, with minimal damage to aircraft or injury to the crew. Availability of the system is, therefore, an essential requirement for flying operations. Indian Air Force (IAF) has arrester barrier at all of their bases for aircrafts up to 20.4 ton mass (MiG, Jaguar, Mirage, Kiran, etc). The induction of SU-30 aircraft in IAF necessitated the need of arrestor barriers for 40 ton class aircraft since the existing barriers cannot be used for more than 20.4 ton class aircraft. DRDO has successfully developed arrestor barriers for 40 ton class aircraft.


The barrier is raised with the help of stanchion system on a command received through remote control located in ATC tower, when emergency arresting of an aircraft is required. As the net envelopes the aircraft, the pull exerted on the net releases the net bottom from the net anchors and breaks the shear pins in the shear-off couplings, releasing the net top from the suspension system. The purchase tapes attached to the net end loops are pulled through the fair-lead tubes paying out the two energy absorber tape drums, thereby turning the rotary hydraulic brakes. This action generates a uniform braking force, which smoothly decelerates the aircraft to a safe stop.
The energy absorption (max. 13.5 million Joules) in this system is based on water twister technology. This arrester barrier system can arrest the fighter aircraft of 20 ton to 40 ton at a speed of 160 knots. The aircraft stops after a run out distance of 270 m after engagement in the system. Clearance for service-use of barrier has been accorded by Centre for Military Airworthiness & Certification.

DRDO designed AABS for Su30MKI. Good for 40T aircraft at 160kt. Would be more than sufficient for M2K at even higher speed.

Bit confused though, it says max absorption of energy 13.5 MJ but KE of 40T aircraft at 160kt would be ~140 MJ. And the aircraft is supposed to stop 270m after the engagement.

Which AABS was installed at HAL..? I saw someone on twitter claiming it was from some Noida based company. But it could be totally wrong.

http://teksav-teknoloji.com/brosur/Textile-Brake.pdf

Link to specs of ABS from some Turkish company. 32T with max speed of 160Kt. But Energy absorption capacity is 108 MJ. Which makes more sense. Above DRDO article might have typo - 13.5 instead of 135 perhaps.

John Galt International from Mumbai makes the DRDO AABS.
http://www.johngalt.in/documents/JGI-AABS.pdf

[JayS]

i did some basic math on 2 engine turboprop ops between chennai and port blair where the other never found an32 vanished.

ATR72 has 120 min ETOPS rating:
The European Aviation Safety Agency (EASA) has just granted ATR, the European manufacturer of turboprop aircraft, “ETOPS 120 minutes” certification of its new ‘-600’ series ATR aircraft. This ETOPS (Extended-range Twin-engine Performance Standards) certification means that the ATR 42-600 and ATR 72-600 versions can now fly with one engine, as far as 120 flight minutes from any airport at which they can land. “ETOPS 120” thus allows aircraft to provide direct links between airports located at maximum distances equaling four flight hours (two hours maximum flight time from the departure airport plus two hours maximum flight time to the closest airport where to land safely).

its cruise speed is around 400kmph. distance madras to port blair is 1400km. so indeed a ATR72 is cleared to fly on this route - barely with 100km of leeway at each end if caught with 1 engine down in the middle. this is not accounting for headwinds and reduced engine perf in a emergency to keep it cooler.
however it does have western engines from pratt n whitney.

An32 cruises at a faster speed of 470kmph and has a range of 2500km. it was never registered with the west as a civilian airliner so has no formal etops certification. its ivchenko engines are 80s design but seem fairly reliable. what it needs is state of art survival beacon, GCAS, TCAS and enhanced from ground ATC radar monitoring, own transponders on vulnerable sea and mountain routes. we need to invest in saving lives, not valiant post crash recovery missions and list of high tech assets being used.

ETOPS is for Civil airliners. Mil Aircrafts need not have ETOPS certification. Totally agree on bolded part. Why the three services are not working on a highly survivable beacon system to start with with DRDO or private industries. Its quite doable project and should not be too costly as well.

[Singha]

the two major transport command bases in NE are guwahati and jorhat. the routes from there to forward areas have not changed in decades. we should long ago have installed some ground based system and radars to keep a track on ac along these routes as also the operation areas of the Tezpur and chabua based fighter squadrons , formerly MOFTU also - multiple fighters have been lost over arunachal sometimes not found for a long time.

every north south valley in arunachal should have a radar - will help to pickup chinese cruise missiles also.

[chetak]

i did some basic math on 2 engine turboprop ops between chennai and port blair where the other never found an32 vanished.

ATR72 has 120 min ETOPS rating:
The European Aviation Safety Agency (EASA) has just granted ATR, the European manufacturer of turboprop aircraft, “ETOPS 120 minutes” certification of its new ‘-600’ series ATR aircraft. This ETOPS (Extended-range Twin-engine Performance Standards) certification means that the ATR 42-600 and ATR 72-600 versions can now fly with one engine, as far as 120 flight minutes from any airport at which they can land. “ETOPS 120” thus allows aircraft to provide direct links between airports located at maximum distances equaling four flight hours (two hours maximum flight time from the departure airport plus two hours maximum flight time to the closest airport where to land safely).

its cruise speed is around 400kmph. distance madras to port blair is 1400km. so indeed a ATR72 is cleared to fly on this route - barely with 100km of leeway at each end if caught with 1 engine down in the middle. this is not accounting for headwinds and reduced engine perf in a emergency to keep it cooler.
however it does have western engines from pratt n whitney.

An32 cruises at a faster speed of 470kmph and has a range of 2500km. it was never registered with the west as a civilian airliner so has no formal etops certification. its ivchenko engines are 80s design but seem fairly reliable. what it needs is state of art survival beacon, GCAS, TCAS and enhanced from ground ATC radar monitoring, own transponders on vulnerable sea and mountain routes. we need to invest in saving lives, not valiant post crash recovery missions and list of high tech assets being used.

ETOPS is for Civil airliners. Mil Aircrafts need not have ETOPS certification. Totally agree on bolded part. Why the three services are not working on a highly survivable beacon system to start with with DRDO or private industries. Its quite doable project and should not be too costly as well.

why this insistence on DRDO development for a device that is very easily available off the shelf, just identify, evaluate, buy and install in a time bound fashion.

the device is mechanically very robust and complex, small in size and the eletronics needs survive the crash and also operate reliably and continuously afterwards for some number of days.

We will get into a needless long cycle development process, vested interests, nasty comments and the usual blame game all around with the guranteed delays, cost over runs and at the end of it all, a mediocre product probably the size of a steamer trunk.

A make or buy decision in this case should be made without jingoism getting the way and it would be far cheaper to buy. If the numbers justify it, look for technology transfer as part of the deal.

Also, satnav may be the way to go given the inhospitable and trecherous terrain in which they operate. Alternatively why not simply use the easily and economically available GPS/GLONASS recievers on the aircraft. Hand held ones are commercially available in the markets of any metro in India.

An ETOPS evaluation should be done for our transport series just so that the risks involved can be realistically assessed and used for decision making when/where appropriate.

don't forget to keep the average age factor of our engines when doing this exercise, though.

[ramana]

JayS, Looks like the HAL arrester barrier handles 20.4 Ton aircraft.
Whats the energy capability?

[ramana]

vcshekar, Do you guys temper the solder in oil bath to relieve stresses in solder?
Are you familiar with David Pinsky algorithm for tin whisker formation?

[Indranil]

The arrestor barrier installed at HAL was supposed to have been able to capture aircrafts moving at up to 160 knots.

[chetak]

The arrestor barrier installed at HAL was supposed to have been able to capture aircrafts moving at up to 160 knots.

upto what weights, saar

[Indranil]

20.4 tons. 13.5 million joules.

AFAIK.

[ramana]

Wonder what factor of safety they used to design the system?
Was 13.5 MJ the ultimate load or it has a safety factor on top?
Usually ground equipment has factor of safety 4.


IR you are using
Kinetic Energy = 0.5*(w/g)*v^2 right?

[chetak]

20.4 tons. 13.5 million joules.

AFAIK.

then we have a teeny problem, right

[Indranil]

I dont know. I am reporting the specs.

Ramana sir, I did not do any calculations.

[ramana]

Chetak, One way is to figure out 20.4 tons at 160 knots equates to how many joules?
JayS wrote 40 ton at 160 knots is 140 MJ.

So if it's correct a 20.4 ton at same speed would be (20.4/40)*140 = 71.4MJ
This 71.4/13.5= 5.3 times greater than max design energy.
So barrier is designed for a gentle arrest of runway overshoot and not violent stopping of accident.

I will also calculate the energy from first principles and post.

[ramana]

Ok from this KE calculator

https://www.ajdesigner.com/phpenergyken ... p#ajscroll


for 20.4 tons and 160 knots the KE is 69106213.80652 or 69.1 MJ

So with in ball park that the barrier is not designed to stop an accident but a runway overshoot type incident.

[rrao]

its quite bizarre ,we could not locate the wreckage of An-32 so far with all the cartosat,Risat and other sensors of su-30mki and UAVs in hand. How can a plane disappear so all of a sudden with out a mayday call !!! Same thing happened with AN-32 over BOB!!! Has it been hijacked and taken to china?
could it be a SAM attack? or EW attack? Very sad to note !!!!

[Indranil]

It is most likely CFIT. In that case, you often dont have any large pieces left.

[ramana]

In that area they still keep finding WWII wrecks.
Could be weather. Similar incident ten years ago.