Civil Aviation Development & Discussion

ramana · Post by **ramana** » 24 May 2010 03:32

Glad to see you back. The thrust reverser failing has occurred in earlier instances. So thats a plausible scenario. In that case it would put the focus on the aircraft.

svinayak · Post by **svinayak** » 24 May 2010 03:59

enqyoob wrote:
Thrust reverser failure on one side. Which means maintenance failure. The pilots never had any chance.

Planes less than 2-3 years - will they have major maintenance problems. Even one assumes AI service level.
Is there a possibility of sabotage. Ground handling people in Dubai airport.

Piloting errors
Faulty equipment
Violations of flight regulations
Design or structural problems
Flight service negligence
Air traffic controller error
Third party carrier selection negligence
Maintenance or repair negligence
Fueling error

BijuShet · Post by **BijuShet** » 24 May 2010 05:01

Glad to see you back YentriSaar

svinayak · Post by **svinayak** » 24 May 2010 05:12

http://www.youtube.com/watch?v=_lKKmU1Zf1A
We take a look at the key questions which need to be answered in the Mangalore air crash.

http://www.youtube.com/watch?v=NYBppKIGd2Y
The expert says here that the pilot knows when he touches that he can land or not

shiv · Post by **shiv** » 24 May 2010 06:20

From email
I am writing my thesis on airline safety and systems to help prevent such tragedies in the aviation community. I believe that the airline pilots should have aborted the landing and engage the thrust levers to increase lift back into the air. I believe that the pilots did not react faster than they should when they knew that the runway was slipping away from them.

In my experience, Pakistan has far better disaster management procedures than India. Clearly the email writer is a prescient person who can reach these conclusions with speed and competence. I have reason to believe that similar deductive reasoning is actively taught in Pakistan - which is why they do not have to spend crores on picking up small pieces of debris under the false name of "evidence". That money can easily be spent on improving facilities - did you see the conditions in which the VIP spectators were watching?

The correct thing to do under the circumstances is to hose the area down and search for sunroof levers - knowing that the actual cause can easily be stated without an elaborate drama.

Time to close the thread.

vina · Post by **vina** » 24 May 2010 07:21

All said,this Mangalore airport runway (esp the 2nd one ) is a disaster that was waiting to happen. Look at google map. It is just a raised long sliver jutting out SE from the point where it touches the old runway and except for a small "bridge" at the beginning, it is surrounded by valleys on 3 sides.

Enqyoob-ud-din -e Gas Turbine is right. You should not expect a commercial airliner carrying passenger to land on a runway that is like an air craft carrier top. It is too dangerous and zero margin for error. Heck in a carrier, if the plane goes off teh side,it goes into the drink. Here it crashes 100 meters into a valley. Your chances of surviving going off a carriers side into the drink is much higher.

Reserve the Mangalore 2nd runway for modern Maharajas.. PM/CM, VIPs, Top shot IAS babus, Hanger on Babu Monkeys and yes IPL organizers and Taliban. Leave the fare paying common Indian public out of it.

The ESG group is right. The 2nd runway should NEVER have been built in the current alignment. Sue the asses off the DGCA babu monkeys who signed off on that and put them behind bars for criminal negligence leading to culpable homicide . A good 10 years doing abacus counting of jail bars and a lot of contemplation will do a world of good for everyone.

Singha · Post by **Singha** » 24 May 2010 08:14

knowing the number of terrorists caught in india who were gulf alumni and had been turned there many years back, the terrorism angle cannot be ruled out by a maintainence person.

hopefully boeing and GE/PW teams can comb the engine debris and recorder data and come up with a good theory.

Dileep · Post by **Dileep** » 24 May 2010 08:33

Hmm, that is the 'catch-the-crane-by-placing-butter-on-the-head' scenario, Singha. If big T want to do something, they would place a bum, not loosen a nut.

Welcome back N^3 saar. You have been missed!

niran · Post by **niran** » 24 May 2010 08:35

Singha wrote: hopefully boeing and GE/PW teams can comb the engine debris and recorder data and come up with a good theory.

already the culprit has been identified, "The dead Pilot" these reports takes awfully long time, and most certainly no blame will be on Boieng, IA, or the Manglore Airstrip, he is dead, no? why not blame him, in some obscure report filed after the incident is forgotten.

Wellkomen Amir-e-N^3.

Singha · Post by **Singha** » 24 May 2010 08:41

GOI may not care to show the skeletons in closet, but Boeing and GOTUS surely will be most interested to know about any failure in their a/c due to lack of or wrong procedures followed, with cost cutting galore most of Massa domestic airline overhaul is now outsourced to shops in latin america (if you didnt know it already). similar "issues" could arise there though periodic visits by airline engg reps for certification can always be "managed" with a bit of spit and polish for the duration.

People here have been quick to pounce on AI but remember there has not been a crash in india for last 15+ yrs with the same AI operating a bunch of much older jets too before they got to order this new lot. nowhere in the world has AI been barred for unsafe engg practises unlike say Garuda who was banned from EU skies.
even the ancient alliance air 737-200 operating on a wing and prayer of shoestring budgets have not had such incidents. my impression is the customer facing side
of AI/IA/AAI may suck somewhat but there are no dangerous compromises on engg side because they dont have to make profits, staff is experienced and enough parts are made available.

lashing out at AI engg is just typical of our self-whipping mentality - "if in doubt beat up the indian and make him confess", which BRF claims not to encourage. why couldnt it be a design failure or parts by Boeing?

Raja Bose · Post by **Raja Bose** » 24 May 2010 08:49

N^3, Welcome back sir! Great to see you back.

Some news sites were claiming that the black box has been recovered while others are saying only the CVR part and the FDAU has been recovered - any updates on the news channels in India? Has the FDR been actually recovered?

N^3's scenario is one worth considering and if true, nothing could have saved the poor souls. I hope instead of whitewashing the incident and only looking to cover their bums, for a change the babus do try to find out what really happened and not just conveniently blame the "heathen" Serb pilot. But then that might be hoping too much....

shiv · Post by **shiv** » 24 May 2010 09:10

niran wrote: already the culprit has been identified, "The dead Pilot" these reports takes awfully long time, and most certainly no blame will be on Boieng, IA, or the Manglore Airstrip, he is dead, no? why not blame him, in some obscure report filed after the incident is forgotten.

"Pilot Error under scanner"

Dead men tell no tales, and therefore they hide all the vital information that proves that everyone alive is innocent. Withholding information from the law is itself a crime. It is a crime to be dead after being witness to such an event.

Please wake me up when the next accident occurs.

ramana · Post by **ramana** » 24 May 2010 09:39

chetak, Sysem accidents are described here for starters.

http://en.wikipedia.org/wiki/System_accident
Please read and tell me.

vina I recall a case where the thrust reverser deployed inadvertently in US crash. May be there are multiple issues: Runway orientation, length, thrust reverser issues.

svinayak · Post by **svinayak** » 24 May 2010 09:55

manish · Post by **manish** » 24 May 2010 10:46

vina wrote: The ESG group is right. The 2nd runway should NEVER have been built in the current alignment. Sue the asses off the DGCA babu monkeys who signed off on that and put them behind bars for criminal negligence leading to culpable homicide . A good 10 years doing abacus counting of jail bars and a lot of contemplation will do a world of good for everyone.

vina saar, I have absolutely no knowledge of aero stuff, I do know that Mangalore Airport expansion project was delayed for a very long time due to land acquisition issues. The major sticking point was a church (there were also a temple and a mosque, just to make it sekkoolar) situated at the site. The priest refused to back down even as the rest vacated the land and I am not too sure if the PIL filers were actually contesting the development on technical grounds alone (the technical points might still be valid, I am not qualified to comment on that).

I might be terribly wrong here about their intentions, but this is just as an FYI for the gurus who are debating the issues.

Also, the newly inaugurated terminal is at the far end of the new runway. Any expansion of the runway would probably need to go over the KR tracks. Can certainly be done, just the way the current 2nd runway was laid - fill up the valley.

BTW as a local, I want to say a few things here. We locals do need our airport, no matter what. People have fought long and hard for this airport, and if there are deficiencies, they should be fixed rather than clamping down restrictions saying accidents can happen. As Dileep saar attests, I doubt any plane would survive plowing through the boundary walls at near take-off speeds - hitting a building, or a 61 feet statue of Lord Shiva or a shanty town would all result in the same thing - a catastrophic loss of life. Please do not think that we are insensitive - Mangalore has lost more of its own children in this horrific crash than any other single place - but that airport is vital to us and we have had to fight and pray to get it. Just read archived articles about the airport on local news portals like Mangalorean.com or Daijiworld and see the kind of longing the locals have had for this airport to be developed and brought to an international standard. It is far from perfect, but it is all that we have.

My 2 cents.

AdityaM · Post by **AdityaM** » 24 May 2010 10:49

A lot is being made out about 'expat pilots'.
Can't understand how having an indian pilot over an expat pilot can prevent such a crash.

Afterall, this is an international airport. foreign airlines employing foreign pilots would also be using it.
the 'expat pilot' logic only works if all foreign airlines fly desi pilots into india.

This incident is being used by various lobbies to serve their purposes.

Singha · Post by **Singha** » 24 May 2010 10:52

there are a huge number of mangaloreans both abroad and working in places like blr. scrapping the airport is not an option. but some kind of arrester/sandpit recovery system on a very strong scale might be needed all along the runway sides and end (by more earth filling if need be) that can contain a charging 737 weight. and replicated on tabletop apts nationwide. even planting special dead plam trees in a mesh format might serve as a biological barrier.

manish · Post by **manish** » 24 May 2010 11:03

AdityaM wrote: This incident is being used by various lobbies to serve their purposes.

My feelings exactly when I spoke about the lobby group that had filed the PIL earlier.

Singha wrote:there are a huge number of mangaloreans both abroad and working in places like blr. scrapping the airport is not an option.

Mumbai - note that there are more direct flights on larger aircraft on BOM-IXE rather than BLR-MLR. Of course, the technical characteristics of a turboprop vs turbofan probably do affect aircraft choice (BLR-IXE is a much shorter distance as compared to BOM-IXE), as do the commercial concerns of traffic and viability, but still that is a good pointer to the size of the non-resident Mangalorean population there.

Plus the city is the defacto capital of North Malabar-Kasaragod and Kannur districts. And the healthcare and educational centres nearby also attract significant number of outsiders.

Singha · Post by **Singha** » 24 May 2010 11:26

nit surathkal and mangalore refinery are visible in goog earth...

chetak · Post by **chetak** » 24 May 2010 11:35

shiv wrote:Question: If reverse thrusters are in operation won't the throttle be full forward as well?

Boss,

The auto brake will kick in the thrust reversers automatically and immediately on touch down. Auto brake is usually set for critical runways like Mangalore. Very very little chance that it was not set at all.

Depending on the chosen setting of the autobrake ie 1, 2 or 3, the full or partial reverse thrust is automatically deployed. Selection is made to accommodate dry, short or contaminated runways.

Normally one would approach Mangalore with a 1 or 2 auto brake setting. Setting 3 is not usual for Mangalore as the 8000 odd feet of runway is plenty of runway for the B738.

svinayak · Post by **svinayak** » 24 May 2010 11:36

manish wrote:

BTW as a local, I want to say a few things here. We locals do need our airport, no matter what. People have fought long and hard for this airport, and if there are deficiencies, they should be fixed rather than clamping down restrictions saying accidents can happen.

Where are you from kudla? I am also from nearby area. This airport is not going to go away. It is actually easirt to build and extend the runway to 10000ft and more by earth excavation.

http://expressbuzz.com/states/karnataka ... 75864.html

Rs 200 crores could have saved 158 lives
24 May 2010 08:15:06 AM IST
BANGALORE: Could India's worst ever air disaster in over a decade, which claimed 158 lives, have been prevented? The answer is yes. If only the Civil Aviation Ministry had spent more time planning while preparing the blue print for the second runway at the Mangalore airport.
The table top runway, which has been described as a nightmare for pilots, is not a demon as it is made out to be, say pilots and aviation experts.
Roland Salian, a former aeronautical engineer with Air India and who has been associated with the Mangalore airport for decades, told Express that during the construction of the airport and, subsequently, the second runway, suggestions were made to the Ministry to build an extended metallic runway.
"The extended metallic runway is nothing but an additional 1000 meters of air strip, supported by pillars measuring 200 or 300 feet. This would help in cases of emergency." "Providing these facilities would have cost just Rs 200 crore. The extension of the runway can still be done at the Mangalore Airport.
If the same was approved and implemented earlier; the cost would have been recovered by averting this catastrophe and could have saved us the additional expenses. Now we can only be and sustain at the 'damage control mode', which is extremely expensive," he added.
The second runway at the Mangalore airport is 8,838 feet and the edges of the hill drop into the valley from a height of 300 feet.

Singha · Post by **Singha** » 24 May 2010 11:47

imo instead of a bridge thing hanging out over the valley, its better to do earth filling at the other end and extend.

bridges have a way of escalating costs and complexity way out of control. except for J&K railway line we arent exactly swiss masters at such
supertall bridge things.

Gagan · Post by **Gagan** » 24 May 2010 11:49

Here is something I've noticed on Google earth images. Is it alright for the landing lights to be located INSIDE the sandtrap? Won't the sandtrap length and the safety of the be compromised by pillars in the middle of the sandtrap?

So based on the above, here is ver 3.0 of what I think might have happened.

chetak · Post by **chetak** » 24 May 2010 11:52

Acharya wrote:
enqyoob wrote:
Thrust reverser failure on one side. Which means maintenance failure. The pilots never had any chance.
Planes less than 2-3 years - will they have major maintenance problems. Even one assumes AI service level.
Is there a possibility of sabotage. Ground handling people in Dubai airport.

Why should TR failure be maintenance failure, saar?

If no defect is reported by the operating pilot after landing, all systems are quite reasonably assumed to be serviceable for the next flight, both by the flight as well as the maintenance crews. Of course, something can also be discovered during the preflight checks or during the turnaround.

If something fails during the next landing, then some component or system has failed. This will duly be reported by the flight crew and thereafter depending on company policy and the current regulatory authority instructions on the subject, the aircraft will either remain grounded pending repair or the faulty system will be MELed and the aircraft released for limited flight.

vina · Post by **vina** » 24 May 2010 11:57

Wanting the Mangalore airport is legitimate. However, it was built wrongly(or rather extended in the wrong direction). Look at Googlemaps. It is rolling farmland towards East and Northeast, towards Doomeshwari temple. That is the way the runways should extend and land acquisition should happen. This airport and boundaries have a very funny shape , with a long 2.5 kms, "panhandle" extending out over valleys. Clear case of path of least resistance followed to get over land acquisitoin problems and then trying to make do with what you have.

No. To fix this, you need to do some 'real' land acquisition and kicking butt/ wielding danda to the east side. So what if you need to kick butt of some politcos there. If you want it,you need to do it.

Gagan · Post by **Gagan** » 24 May 2010 12:00

The thing to note is that the plane still had sufficient speed when it hit the concrete locator, that its wing broke away.

niran · Post by **niran** » 24 May 2010 12:55

IMO, the problem is not the length, the problem is the runway itself, they should have blown away the hill and build the runway on flat land, mucho great margin for error this way. i was about to board one such flight which over shot the runway no deaths, onlee injuries.

the sequence of happenstance is eerily similar to the AI one, though the result altogether
different.

Qantas flights between London and Sydney, known as the "Kangaroo Route", make the journey in two "hops" with an intermediate landing at either Bangkok, Singapore or Hong Kong for refuelling. This flight began in Sydney earlier that day at 1645 local time, and after more than eight hours flying was approaching Bangkok International Airport at 2245 local time.

During the approach to Bangkok the weather conditions deteriorated significantly, from 8 km visibility half an hour before landing to 750 m at the time of landing. The flight crew observed a storm cloud over the airport and ground reports were that it was raining heavily. However these conditions were common at Bangkok. Seven minutes prior to landing a Thai Airways Airbus A330 landed normally, but three minutes before landing another Qantas aircraft (QF15, a Sydney-Rome via Bangkok service), a Boeing 747, conducted a "go around" due to poor visibility during final approach. The crew of Qantas Flight 1, however, were unaware of this.

The first officer was flying the plane during final approach with both the height and speed high, though within company limits. The rain was now heavy enough that the runway lights were visible only intermittently after each windscreen wiper stroke. Just before touchdown the captain, concerned about the long touchdown point (over a kilometre past the runway threshold) and unable to see the end of the runway, ordered the first officer to perform a "go-around" and the first officer advanced the throttles to TO/GA power. Seeing that visibility had increased markedly and the landing gear contacted the runway, the captain then decided to cancel the go-around by retarding the thrust levers even though he was not flying the plane. This caused confusion as he did not announce his actions to the first officer who was still flying the plane. When overriding the first officer's actions, the captain inadvertently left one engine at TO/GA power and as a result canceled the preselected auto-brake settings.

The landing continued but manual braking did not commence until the aircraft was over 1600 metres down the runway. Company SOP mandated that idle reverse thrust should be used for landings and that flaps should be set at 25 degrees not the maximum of 30 degrees. The combination of flaps 25, no auto-braking, idle reverse thrust, a high and fast approach, a late touch down, poor Cockpit Resource Management and the standing water on the runway surface led to an inevitable runway overshoot.

The aircraft in fact accelerated for a few seconds after touchdown. Then it proceeded to hydroplane and skid its way down the runway, departing substantially from runway centreline. It gradually decelerated, but far too slowly to save the aircraft, which proceeded past the runway end, over a stretch of boggy grassland, colliding with a ground radio antenna as it did so, and came to rest with its nose resting on the perimeter road.

manish · Post by **manish** » 24 May 2010 13:06

niran wrote:IMO, the problem is not the length, the problem is the runway itself, they should have blown away the hill and build the runway on flat land, mucho great margin for error this way.

niranji, that would put hills in the way of the landing approach and take off paths, as the airport would go from being a table top runway to a valley runway!

The regional topography is the key constraint here, as the whole region is almost like the tapering edges of the Western Ghats. For the same reason Kozhikode too has a table-top if I am not mistaken. In fact, I was told that the slopes extend into the ocean as well, making for deeper depths close to the shoreline as opposed to the east coast.

You can't get away from the hills in and around Mangalore. For the same reason, you would be hard pressed to find even a SINGLE straight and level piece of road in and around that city. There are ups and downs and undulations everywhere. And don't let some of the few flat regions shown on Google Maps fool you - many of those are natural water drains and wetlands which get completely flooded and waterlogged during the monsoon.

chaanakya · Post by **chaanakya** » 24 May 2010 13:38

enqyoob wrote:Thanks, etc.. They should reserve Mangalore Airport 400% for use only by VIPs such as Mantris, Top AI Babus, IPL organizers and the Taliban. Or helicopters.

VIPs politicians ,like Cats, have nine lives. Read for yourself

http://news.rediff.com/report/2010/may/ ... flight.htm

A last-minute change in his travel plan saved Congress Member of Legislative Assembly from Kerala [ Images ] A P Abdullakutty from meeting the fate of 158 passengers who died when an Air India [ Images ] Express plane from Dubai [ Images ] crashed near Mangalore airport on Saturday morning.

Abdullakutty initially planned to catch the ill-fated flight to Mangalore since he had to reach his home town Kannur urgently. But he was a bit late to reach the Dubai International Airport and changed his ticket to a flight to Kozhikode instead of the one to Mangalore, in which he had originally planned to fly. To his rude shock, he came to know about the Mangalore air tragedy as soon as he reached Karippur.

Moily has survived this airport years ago, old runway. tumbling aircraft was saved by three laterite rocks lodged at the end of runway, now removed, apparently.

chaanakya · Post by **chaanakya** » 24 May 2010 13:53

Singha wrote:knowing the number of terrorists caught in india who were gulf alumni and had been turned there many years back, the terrorism angle cannot be ruled out by a maintainence person.

hopefully boeing and GE/PW teams can comb the engine debris and recorder data and come up with a good theory.

I had this suspicion when one of the passenger ,umar farook, spoke of loud noise and vibrations.

BTW CVR transcript, leaked to times now

, indicates pilot saying 'overshoot', 'overshoot', just after ATC advised to abort landing.

chetak · Post by **chetak** » 24 May 2010 14:19

vina wrote:Wanting the Mangalore airport is legitimate. However, it was built wrongly(or rather extended in the wrong direction). Look at Googlemaps. It is rolling farmland towards East and Northeast, towards Doomeshwari temple. That is the way the runways should extend and land acquisition should happen. This airport and boundaries have a very funny shape , with a long 2.5 kms, "panhandle" extending out over valleys. Clear case of path of least resistance followed to get over land acquisitoin problems and then trying to make do with what you have.

No. To fix this, you need to do some 'real' land acquisition and kicking butt/ wielding danda to the east side. So what if you need to kick butt of some politcos there. If you want it,you need to do it.

Not to troll or flame bait, but

A majority of pilots operating to Mangalore seem to be comfortable with the airport. The tabletop is gradual as per them and the aircraft should normally stop even on the slope after being obstructed by trees, rocks whatever.

In this case, the aircraft went off the edge under full power, and with one wing only. Had there been a continued use of the thrust reversers, the aircraft would have stopped short on the runway itself with about 2-300 feet to spare. May be they would have burst all tires but what the hell, they would not have landed up in their terrible plight.

Pilots again say that tire burst on main gear will not cause much of a yaw but the aircraft will be wing low on that side but continue to go almost straight ahead.

In case of nose tire burst, it will assume a bit of a nose down position but continue to plough on almost straight ahead.

The question of a visicious yaw comes up if one main gear was on soft ground while the other was still on concrete or assymeteric thrust from the engines from attempting a runway go around after deployment of thrust reversers.

The second option was the worst because the thrust reversers would have bled off speed to well below the un stick speed of the Boeing and the Captain did not have enough runway to lift off again. He was already a goner in the short final approach stage itself where he seems to have been hot and high.

Who did the actual landing?? The Captain or the First Officer??

Mangalore is a Captain only airport, meaning that the First Officer was not authorised to land the aeroplane.

The Mangalore runway meets ICAO specs for run off area and has operated for a decade or more without mishap.

This is a one off accident. No pilot refuses to fly to Mangalore but many ABSOLUTELY refuse to fly to Shimla or Kulu. I repeat, REFUSE to fly to Shimla and Kulu airports. Shimla has a dead drop table top and is very short and Kulu lies in a valley with the decision height being around 10,000 feet while the runway is at a height of about 4000 odd feet. It has a single direction take off with very little chance of escape in the case of a single engine.

So take your pick. There are worse airports than Mangalore.

chaanakya · Post by **chaanakya** » 24 May 2010 14:26

Acharya wrote: Where are you from kudla? I am also from nearby area. This airport is not going to go away. It is actually easirt to build and extend the runway to 10000ft and more by earth excavation.

http://expressbuzz.com/states/karnataka ... 75864.html
Roland Salian, a former aeronautical engineer with Air India and who has been associated with the Mangalore airport for decades, told Express that during the construction of the airport and, subsequently, the second runway, suggestions were made to the Ministry to build an extended metallic runway.
"The extended metallic runway is nothing but an additional 1000 meters of air strip, supported by pillars measuring 200 or 300 feet. This would help in cases of emergency." "Providing these facilities would have cost just Rs 200 crore. The extension of the runway can still be done at the Mangalore Airport.

Perhaps like this

or a frightening ones like these

Traffic halt as plane is landing at Gibraltar airport (just like a railway crossing)

We do have many solutions available, limited only by imagination.

And many more

http://www.airliners.net/search/photo.s ... or=inferno

sunilUpa · Post by **sunilUpa** » 24 May 2010 14:41

Mangalore is my home port, have landed there umteen times. My family will be landing there in 2 weeks time.

I read that similar accident happend in Torronto (similar airport) and all survived. Is the emergency response inadequate in India? Is there access roads surrounding the airport?

manish · Post by **manish** » 24 May 2010 14:52

sunilUpa wrote:Mangalore is my home port, have landed there umteen times. My family will be landing there in 2 weeks time.

I read that similar accident happend in Torronto (similar airport) and all survived. Is the emergency response inadequate in India? Is there access roads surrounding the airport?

Simple answer - no. The spot as one could see on TV was connected by a narrow 'path'. The airport has a road all around the perimeter which is used by the follow-me type vehicles and CISF guards, but none on the periphery (at the bottom of the hill). That would have allowed a faster response.

The area where the crash took place and its surrounding are definitely candidates for development as people have been suggesting building a railway station at Kenjar to provide rail connectivity to the airport and its new terminal. There were also plans in place to build taxiways to take planes to the new terminal.

manish · Post by **manish** » 24 May 2010 14:59

chaanakya wrote:
Perhaps like this
..
..

There is an example closer home at Chennai (MAA) where they are building a runway extension over the Adyar river, supported by a bridge standing over hundred of pillars.

The country’s first bridge over which a runway will be laid, will be supported by 477 pillars. Around 2,440 pre-stressed concrete girders will be placed over the pillars to make it an integrated structure. The bridge will be 200m long across the river and 462m wide.

chaanakya · Post by **chaanakya** » 24 May 2010 15:06

Scenario one

Aircraft permitted to Land, 4 Km away from runway.
Approach speed 165-170 Kts
Descent angle steep ( more than 3-4 deg)
Landing speed 160 Kts
Flare up (for smooth touch down/reduce landing speed)
Glides to 1000 mts while still descending
ATC , seeing this, asks to abort
Pilot says overshoot overshoot
Speed 140kts at TD
Pushes the thrust lever to max ( from idle)
Plane continues to descend
Rear carriage wheels touch down and autobrake engages
Speed 120Kts
Pilot pushes autobrake to disengage
Thruster increase the speed, ( 8 second to respond)
Nose comes down heavily,
nose tyre bursts
Gives a jerk , vibrations and drag
Plane speeds to the end of runway again speed 140 Kts
unable to gather liftoff speed
Left wing touches one of the localiser in sand trap, breaks up
Plane cartwheels left and tumbles into valley breaking up in two or three sections
Some jump , some thrown off
plane races down the valley catching fire ignited by aviation fuel from left wing tank.
On floor of valley, it bursts into deep flame.

( in this scenario, reverse thrusters are not used since ATC commanded to abort before touch down)
Refer to Gagan's Ver 3.0,

chaanakya · Post by **chaanakya** » 24 May 2010 15:09

manish wrote:

There is an example closer home at Chennai (MAA) where they are building a runway extension over the Adyar river, supported by a bridge standing over hundred of pillars.

The country’s first bridge over which a runway will be laid, will be supported by 477 pillars. Around 2,440 pre-stressed concrete girders will be placed over the pillars to make it an integrated structure. The bridge will be 200m long across the river and 462m wide.

Mumbai has runway over mithi river , you can see river going under runway and emerging on the other side.

chetak · Post by **chetak** » 24 May 2010 15:29

chaanakya wrote:Scenario one

Plane speeds to the end of runway again speed 140 Kts

Try again saar, at 140 Kts, the aircraft would have got airborne!!!

The Boeing typically rotates at about 120 Kts onwards depending on the weight.

niran · Post by **niran** » 24 May 2010 17:12

chaanakya wrote: ( in this scenario, reverse thrusters are not used since ATC commanded to abort before touch down)
Refer to Gagan's Ver 3.0,

Reverse Thrusters will have engaged automatically as soon as the main under carriage touch down and wheels starts spinning.
Aborting a Landing cannot be done after some stage, different for different Aircrafts
and Airports and Aircraft Weight wagera, most prollay reverse thrust engaged, Pilot/Copilot
have to disengage it, then, push thrust to full power, all these autopilot have to be disengage first, all these take valuable seconds, which given the make of Manglore they
did not have.

or

to increase the reverse thrust, pilot pushes the power to maximum, some thing went wrong and Aircraft went out of control.

chaanakya · Post by **chaanakya** » 24 May 2010 18:21

chetak wrote:
chaanakya wrote:Scenario one

Plane speeds to the end of runway again speed 140 Kts
Try again saar, at 140 Kts, the aircraft would have got airborne!!!

The Boeing typically rotates at about 120 Kts onwards depending on the weight.

To get airborne
Boeing 737-800
V1 = 145 KIAS (descision)
Vr = 150 KIAS (rotate)
Pitch 10 deg. nose up
V2 = 160 KIAS (safety speed)

So I presume it could have sped upto 140 Kts ) Knots Indicated Air Speed)
But hit sand trap (90 Mts) and then localiser.
Just presumed.
Welcome to improve various scenario .
Mostly, I referred to technical literature of Boeing Official Site for info on 737-800 only. There are other things which I have not yet taken into account, as no specific info could be made available for this crash without DFDR.
This is just hypothesis to be shred into pieces

niran wrote:Reverse Thrusters will have engaged automatically as soon as the main under carriage touch down and wheels starts spinning.

As per manual , only autobrake would engage. CAT-I airport , no autoland so no auto pilot, refer to prev post. On Landing Pilot needs to take some steps to engage reverse thrust.For engaging reverse thrusters on needs to flick the reverse thrust lever to On position and then push the throttle forward from IDLE. Plane needs 8 seconds before it responds to full throttle in any case. Add one or two seconds for Thrust reverse lever to ON position. You get 10 seconds. add another one second to get throttle to idle, one second to put thrust reverse lever to Off and then throttle to max. Another 8 second for response to kick in. Total of 20 seconds before power to MAX after engaging then disengaging RT.
I think , if pilot was told to abort, he would not have engaged RT, but continue to descent, being in glide scope , with nose up.Normally Boeing would take 100 ft AGL to start going up on MAX provided speed is Approach speed. I think it would be landing speed. So once it touched ground, autobrake engaged while pilot put power MAX. Then he might rush to disengage brake for take off.

let us say imaginary scenario. there could be other situations inside cockpit. and Boeing's performance margin would not allow laws of physics to be violated.