Missing Malaysia Airlines jet carrying 239 triggers Southeast Asia search

[khaosai]

Having had to do Aerodynamic Stability calculations for final year exam, it left me with years of nightmares complete with LaPlace transformations

To explain simple for stability in pitch , from the nose going backwards the(CG? llowing applies:-

1. Center of a Gravity (CG ) is always in front of main wing center of lift

2. Main wing of course lifts

3. Horizontal stabiliser ( tail ) is a negative wing, meaning it pulls down like a formula one car tail wing.

Only reason you waste fuel on a wing that pulls you down to earth is - stability.

So Aerodynamic stability is easy to now fathom

1. In stable air/ constant speed, is you get gust of wind ( air speed increase ), more lift on main wing and more down pull on tail.

Nose will pitch up

2. If nose pitch up, angle of attack on tail will reduce resulting in less negative lift. Since CG is forward of main wing, this will pull nose down.

So what happens - add more engine power is same as a gust of wind, nose will pitch up. Since there are no "shock absorbers", it will be like a spring which oscillates for a while ( speed / pitch / vs ) will oscillate until new steady state

Simply put

Power controls vertical speed - up/down- alt hold

Sent from my iPhone using Thaivisa Connect Thailand mobile app

Sorry, Skippy, just not what we're talking about. It's not a question of what happens in a gust of wind. It's what happens with both engines out, all the way down to the water that we're concerned with.

So there is a RAT which can provide hydraulic power to the flight controls, even with both engines out. The pilot, if still alive, COULD have attempted a controlled ditching.

If the pilot was not alive, then the question is what would the aircraft do on its own. Would the RAT deploy automatically? If so, would autopilot be restored and provide a "controlled" descent ( e.g., a reasonably stabilized ("stabilized" in terms of predictability and adherence to some programmed set of rules, not "stabilized" as in dynamically stable)? If so, even without a pilot at the controls maybe there could've been something other than a high-speed/high angle/high rate-of-descent impact.

Hi,

RAT will automatically deploy. No pilot means no autopilot restored.

[hawker9000]

Having had to do Aerodynamic Stability calculations for final year exam, it left me with years of nightmares complete with LaPlace transformations

To explain simple for stability in pitch , from the nose going backwards the(CG? llowing applies:-

1. Center of a Gravity (CG ) is always in front of main wing center of lift

2. Main wing of course lifts

3. Horizontal stabiliser ( tail ) is a negative wing, meaning it pulls down like a formula one car tail wing.

Only reason you waste fuel on a wing that pulls you down to earth is - stability.

So Aerodynamic stability is easy to now fathom

1. In stable air/ constant speed, is you get gust of wind ( air speed increase ), more lift on main wing and more down pull on tail.

Nose will pitch up

2. If nose pitch up, angle of attack on tail will reduce resulting in less negative lift. Since CG is forward of main wing, this will pull nose down.

So what happens - add more engine power is same as a gust of wind, nose will pitch up. Since there are no "shock absorbers", it will be like a spring which oscillates for a while ( speed / pitch / vs ) will oscillate until new steady state

Simply put

Power controls vertical speed - up/down- alt hold

Sent from my iPhone using Thaivisa Connect Thailand mobile app

Sorry, Skippy, just not what we're talking about. It's not a question of what happens in a gust of wind. It's what happens with both engines out, all the way down to the water that we're concerned with.

So there is a RAT which can provide hydraulic power to the flight controls, even with both engines out. The pilot, if still alive, COULD have attempted a controlled ditching.

If the pilot was not alive, then the question is what would the aircraft do on its own. Would the RAT deploy automatically? If so, would autopilot be restored and provide a "controlled" descent ( e.g., a reasonably stabilized ("stabilized" in terms of predictability and adherence to some programmed set of rules, not "stabilized" as in dynamically stable)? If so, even without a pilot at the controls maybe there could've been something other than a high-speed/high angle/high rate-of-descent impact.

Hi,

RAT will automatically deploy. No pilot means no autopilot restored.

I see. So does that mean flight control surfaces would just freeze in the position they were in when power & hydraulics dropped offline? I can believe that inherent stability characteristics as described by skippy would sort of "kick in" and provide some sort of "best power off glide", provided flight control surfaces can move, but not if they freeze up.

[khaosai]

Having had to do Aerodynamic Stability calculations for final year exam, it left me with years of nightmares complete with LaPlace transformations

To explain simple for stability in pitch , from the nose going backwards the(CG? llowing applies:-

1. Center of a Gravity (CG ) is always in front of main wing center of lift

2. Main wing of course lifts

3. Horizontal stabiliser ( tail ) is a negative wing, meaning it pulls down like a formula one car tail wing.

Only reason you waste fuel on a wing that pulls you down to earth is - stability.

So Aerodynamic stability is easy to now fathom

1. In stable air/ constant speed, is you get gust of wind ( air speed increase ), more lift on main wing and more down pull on tail.

Nose will pitch up

2. If nose pitch up, angle of attack on tail will reduce resulting in less negative lift. Since CG is forward of main wing, this will pull nose down.

So what happens - add more engine power is same as a gust of wind, nose will pitch up. Since there are no "shock absorbers", it will be like a spring which oscillates for a while ( speed / pitch / vs ) will oscillate until new steady state

Simply put

Power controls vertical speed - up/down- alt hold

Sent from my iPhone using Thaivisa Connect Thailand mobile app

Sorry, Skippy, just not what we're talking about. It's not a question of what happens in a gust of wind. It's what happens with both engines out, all the way down to the water that we're concerned with.

So there is a RAT which can provide hydraulic power to the flight controls, even with both engines out. The pilot, if still alive, COULD have attempted a controlled ditching.

If the pilot was not alive, then the question is what would the aircraft do on its own. Would the RAT deploy automatically? If so, would autopilot be restored and provide a "controlled" descent ( e.g., a reasonably stabilized ("stabilized" in terms of predictability and adherence to some programmed set of rules, not "stabilized" as in dynamically stable)? If so, even without a pilot at the controls maybe there could've been something other than a high-speed/high angle/high rate-of-descent impact.

Hi,

RAT will automatically deploy. No pilot means no autopilot restored.

I see. So does that mean flight control surfaces would just freeze in the position they were in when power & hydraulics dropped offline? I can believe that inherent stability characteristics as described by skippy would sort of "kick in" and provide some sort of "best power off glide", provided flight control surfaces can move, but not if they freeze up.

Hi,

The hydraulics won't drop offline but would probably maintain the same position they were in when the generators failed and attempt to maintain trim reference speed (TRS)

You will only have centre hydraulic system pressure available, powered by the RAT. Limited flight control surfaces will be available. Left and right aileron. Right flaperon. Six spoiler panels out of a total of 14. Stabiliser and left elevator.

Will try it if have some free simulator time and see the results, but reckon the up down phugoid motion will be the end result, getting larger in magnitude until impact.

[Tywais]

I see. So does that mean flight control surfaces would just freeze in the position they were in when power & hydraulics dropped offline?

Power and hydraulics will continue to function but at a reduced level. Article below.

Even if its engines fail, a modern aircraft can glide for very long distances if they start from a high enough altitude, but power for flight controls is needed for the crew to have an opportunity to land the plane safely. Ram air turbine (RAT) systems built by Hamilton Sundstrand in Rockford, Ill. can provide this emergency power in the unlikely event of a complete engine, hydraulic, or electrical failure. Hamilton Sundstrand supplies hydraulic RATs, electric RATs, and hybrid RATs (which combine an electric generator and pump). RATs are standard parts of the redundancy backup systems on modern-day business, regional, and large commercial jets, as well as military aircraft.

Ready when needed

Tom Gillis, director of engineering, Hamilton Sundstrand Electric Systems, explains that the RAT package consists of a turbine that is deployed into the external air stream by a spring-loaded actuator during an emergency situation. The turbine then powers a pump to pressurize the plane’s central hydraulic channel or a generator to power the essential electrical bus (or both in the case of a hybrid RAT). By judiciously selecting only essential hydraulic and/or electric functions, a crew can use the RAT output to maneuver a plane like a glider and land safely. In fact, there have been about 15 documented cases in which Hamilton Sundstrand RATs have been used and saved almost 2000 lives.

<snip>

Once the RAT is deployed and the turbine is governing, the pump, generator, or both put out power that is approximately 10% of what the aircraft requires for full hydraulic/ electric operation. This is enough to operate flight controls, linked hydraulics, and flight-critical instrumentation. The RAT power output will be reduced when the aircraft‘s speed drops — a factor with which pilots have to contend during emergency procedures.

Full article here - hydraulicspneumatics

[Tywais]

Your question was, when an airplane encounters all engines failure, does the plane start flipping and crash, or continue to fly while losing height? If it continues to fly, how long does it last and how safe it is to land the aircraft ?

As I have described earlier, the aircraft does not flip or crash. It continues to fly at an optimum gliding speed, a speed much lower than its cruising speed.

However, it may not be able to maintain its cruising altitude but continues to lose height at a rate of about 3500 to 4500 feet per minute. This will give an aircraft, cruising at 35,000 feet about 10 minutes to fly a distance of about 40 to 50 nautical miles. Remember, pilots have been trained to restart/relight the engines whenever they encounter total engine failures. If restarting the engines were unsuccessful, they would have no choice but to carry out a prepared forced landing - just like what the Canadian pilot did to the crippled Boeing 767.

What happens when all engines fail

[Chicog]

Your question was, when an airplane encounters all engines failure, does the plane start flipping and crash, or continue to fly while losing height? If it continues to fly, how long does it last and how safe it is to land the aircraft ?

As I have described earlier, the aircraft does not flip or crash. It continues to fly at an optimum gliding speed, a speed much lower than its cruising speed.

However, it may not be able to maintain its cruising altitude but continues to lose height at a rate of about 3500 to 4500 feet per minute. This will give an aircraft, cruising at 35,000 feet about 10 minutes to fly a distance of about 40 to 50 nautical miles. Remember, pilots have been trained to restart/relight the engines whenever they encounter total engine failures. If restarting the engines were unsuccessful, they would have no choice but to carry out a prepared forced landing - just like what the Canadian pilot did to the crippled Boeing 767.

What happens when all engines fail

Or get ready for it like the crew of BA009 did.

[skippybangkok]

Khaosai - Since the hydraulic pumps are connected to the core of the turbine,baca use of wind milling I assume you will have some slow hydraulics. I believe 777 is still steel cable from yoke to servo, so should still work

Tywais - if all dead and just on autopilot, I think it would go into a spin either on single engine ops, or when second fail due to rudder and aileron inputs .... Khaosai should be able to confirm if single engine can still be handled by auto pilot.....

As such - looks like a nice smooth landing

Sent from my iPad using ThaiVisa app

[RubbaJohnny]

Eleven terrorists with links to Al Qaeda have been arrested on suspicion of being involved in the disappearance of MH370

• Suspects were arrested in the capital Kuala Lumpur and the state of Kedah
• Said to members of violent new terror group said to be planning attacks
• Interrogations came after demands from agencies including FBI and MI6
• Manifest revealed presence of consignment but did not reveal its contents
• Airline has admitted 200kg of lithium batteries was among the items
• It refused to say what else, citing 'legal reason' related to 'ongoing' probe

By RICHARD SHEARS and MAIL ON SUNDAY REPORTER and WILLS ROBINSON

PUBLISHED: 11:20, 3 May 2014 | UPDATED: 15:57, 4 May 2014

9,511 shares

1,099

View
comments

A group of 11 terrorists with links to Al Qaeda were yesterday being interrogated on whether they are behind the disappearance of Malaysia Airlines flight MH370.

The suspects were arrested in the capital Kuala Lumpur and in the state of Kedah last week and are members of a violent new terror group said to be planning bomb attacks in Muslim countries.

The interrogations come after international investigators, including the FBI and MI6, asked for the militants, whose ages range from 22 to 55 and include students, odd-job workers, a young widow and business professionals, to be questioned intensively about Flight MH370.

Link to source

[RubbaJohnny]

Eleven terrorists with links to Al Qaeda have been arrested on suspicion of being involved in the disappearance of MH370 the d mail avers.

Nearly two months after the Beijing-bound plane vanished soon after take-off from Kuala Lumpur, no trace has been found despite a huge sea search costing hundreds of millions of pounds. It is thought to have crashed into the Indian Ocean with 239 people on board.

An officer with the Counter Terrorism Division of Malaysian Special Branch said yesterday the arrests had heightened suspicion that the flight’s disappearance may have been an act of terrorism.

‘The possibility that the plane was diverted by militants is still high on the list and international investigators have asked for a comprehensive report on this new terror group,’ the officer said.

In interviews conducted so far, some suspects have admitted planning ‘sustained terror campaigns’ in Malaysia but denied being involved in the disappearance of the airliner, he added.

Source here

[Tywais]

MH370: Militants detained have nothing to do with missing plane, says IGP

PETALING JAYA (May 4): Inspector General of Police Tan Sri Khalid Abu Bakar today rubbished news report from two foreign medias claiming that 11 suspected militants nabbed over the past week were being interrogated over the disappearance of the missing Malaysia Airlines MH370 aircraft.

According to news reports from UK's Daily Mirror and International Business Times published yesterday, it claimed that 11 terrorists who believed to have links with al Qaeda were being questioned over the vanished jetliner.

The report quoting an officer with the Counter Terrorism Division of Malaysian Special Branch said the arrests had heightened suspicion that the flight's disappearance may have been an act of terrorism.

“The possibility that the plane was diverted by militants is still high on the list and international investigators have asked for a comprehensive report on this new terror group,” the report was quoted as saying.

However, Sin Chew Daily reported that Khalid denied the allegations and said: “That's rubbish! This has nothing to do with the plane.”

More here fz.com

[RubbaJohnny]

Well at least it shows some of them are telling lies some of the time.

It so much easier here where folks are more consistent and moral turpitude being so repugnant to honest buddhist natives of LOS

[F4UCorsair]

Latest report

https://au.news.yahoo.com/thewest/latest/a/23222670/mh370-had-to-have-human-interference/

In view of there being no debris, I have difficulty with this, "When it ran out of fuel, it was at 30,000ft, about 1000km west of Exmouth."

[hawker9000]

We can't really say " there's no debris". No debris has been found, and it's a very very (very) large ocean. I still can't figure out how much credence to assign to these "pings". First they were "sure" of a flight path, then they adjusted that to conform to debris or an oil slick (I forget which), then there was talk of a northern path/southern path ambiguity... Everything we hear about this incident turns out at some point to have been a shot in the dark. I'm not totally convinced this airplane isn't hidden in a hangar somewhere.

[P45Mustang]

We can't really say " there's no debris". No debris has been found, and it's a very very (very) large ocean. I still can't figure out how much credence to assign to these "pings". First they were "sure" of a flight path, then they adjusted that to conform to debris or an oil slick (I forget which), then there was talk of a northern path/southern path ambiguity... Everything we hear about this incident turns out at some point to have been a shot in the dark. I'm not totally convinced this airplane isn't hidden in a hangar somewhere.

I have sympathy for that view.

Wouldn't be surprised at anything tbh.

Failed or aborted 9/11 attempt was my first hunch.

Not sure if what we know can fit into that theory though.

[hawker9000]

We can't really say " there's no debris". No debris has been found, and it's a very very (very) large ocean. I still can't figure out how much credence to assign to these "pings". First they were "sure" of a flight path, then they adjusted that to conform to debris or an oil slick (I forget which), then there was talk of a northern path/southern path ambiguity... Everything we hear about this incident turns out at some point to have been a shot in the dark. I'm not totally convinced this airplane isn't hidden in a hangar somewhere.

I have sympathy for that view.

Wouldn't be surprised at anything tbh.

Failed or aborted 9/11 attempt was my first hunch.

Not sure if what we know can fit into that theory though.

It's just that what we "know" seems to be a moving target...

[3NUMBAS]

MH370: satellite data will be rechecked and search on ocean floor widened

Daniel Hurst in Canberra

• theguardian.com, Monday 5 May 2014 07.27 BST

quote

The interpretation of satellite data underpinning the search for missing Malaysia Airlines flight MH370 will come under fresh scrutiny on Wednesday, while authorities seek equipment to look deeper in the southern Indian Ocean.

Australia’s deputy prime minister, Warren Truss, flagged the information “audit” after meeting with senior representatives of the Malaysian and Chinese governments in Canberra on Monday.

They were meeting to plan the next stage of an operation which is yet to find any sign of the Boeing 777 that went missing nearly two months ago during a flight from Kuala Lumpur to Beijing with 239 people aboard.

Australian-led search efforts focused on the southern Indian Ocean, backed up by analysis of satellite data that suggested the plane may have travelled south to a remote area off the west Australian coast. But the number of personnel involved is now being reduced and Truss said it was likely any wreckage had sunk to the deep sea floor before aerial searches of the area began.

Truss said the new phase of the operation would focus on intensifying the ocean floor search over a much larger area. Governments involved in the search planned to launch a tender process to gain access specialised equipment required for this task, he said, although the details of likely financial contributions remained unclear.

Truss said international experts would attend a follow-up meeting in Canberra on Wednesday to analyse all data and information collected so far “that is likely to help us identify the path” flight MH370 took on 8 March.

“It will be something of an audit of the information that has been collected since the beginning of the search,” he said at a joint media conference with Malaysian and Chinese ministers on Monday.

“It’ll also look again at the satellite information that has been accumulated so that we can make sure that it’s been accurately interpreted, whether it should lead to some further search for information, and look generally at the way in which we’ve been able to extrapolate from the hard information that’s been received to actually identifying a search area.”

The former Australian defence chief heading the joint agency coordination centre, Air Chief Marshal Angus Houston, said: “We've got to this stage of the process where it's very sensible to go back and have a look at all of the data that's been gathered, all of the analysis that's been done, and make sure that there are no flaws in that.”

Houston said hundreds of personnel had been involved in the search but it was now moving into a phase where the number of people was “much less”. The deep water search would involve even fewer people, Houston said.

http://www.theguardian.com/world/2014/may/05/mh370-data-rechecked-ocean-search-widened

Last week, Malaysia released its most comprehensive account yet of what happened to Flight MH370, detailing the route the plane probably took as it veered off course and the confusion that followed.

U.S. President Barack Obama had publicly promised to commit more assets, but government sources say the United States is keen to begin passing on the costs of providing the expensive sonar equipment the officials say they are trying to source.

Officials are contacting governments and private contractors to find out whether they have specialized equipment that can dive deeper than the Bluefin-21, an unmanned sub that has spent weeks scouring the seafloor in an area where sounds consistent with a plane's black box were detected in early April.

The Bluefin has been limited by the fact that it can dive only to depths of 4.5 kilometers (2.8 miles) - and parts of the search zone are likely deeper than that. Adding to the difficulties is the fact no one really knows exactly how deep the water in the search area is.

'I don't know that anyone knows for sure, because it's never been mapped,' Truss said, adding that detailed mapping of the seafloor will be a key focus of the next phase of the search.

In addition to deeper diving capabilities, the new equipment will be able to send information back to crews in real time. The Bluefin's data can be downloaded only once it returns to the surface after each of its 16-hour dives.

It will likely take another two months before any new equipment is in the water, Truss said. The Bluefin will continue to be used in the meantime, though its search is currently on hold while the Ocean Shield, which has the sub on board, is taking on supplies at a base in Western Australia.

Read more: http://www.dailymail.co.uk/news/article-2620443/Back-drawing-board-hunt-MH370-officials-admit-weve-nothing.html#ixzz30pKq6l9w
Follow us: @MailOnline on Twitter | DailyMail on Facebook

[Chicog]

I'm telling you, give the job to James Cameron.

[coma]

Your question was, when an airplane encounters all engines failure, does the plane start flipping and crash, or continue to fly while losing height? If it continues to fly, how long does it last and how safe it is to land the aircraft ?

As I have described earlier, the aircraft does not flip or crash. It continues to fly at an optimum gliding speed, a speed much lower than its cruising speed.

However, it may not be able to maintain its cruising altitude but continues to lose height at a rate of about 3500 to 4500 feet per minute. This will give an aircraft, cruising at 35,000 feet about 10 minutes to fly a distance of about 40 to 50 nautical miles. Remember, pilots have been trained to restart/relight the engines whenever they encounter total engine failures. If restarting the engines were unsuccessful, they would have no choice but to carry out a prepared forced landing - just like what the Canadian pilot did to the crippled Boeing 767.

What happens when all engines fail

At the rate of decent you mentioned. 3500 to 4500 feet per minute. How does that look when it comes into contact with the earth's surface ? Catastrophic ?

[tigermonkey]

Your question was, when an airplane encounters all engines failure, does the plane start flipping and crash, or continue to fly while losing height? If it continues to fly, how long does it last and how safe it is to land the aircraft ?

As I have described earlier, the aircraft does not flip or crash. It continues to fly at an optimum gliding speed, a speed much lower than its cruising speed.

However, it may not be able to maintain its cruising altitude but continues to lose height at a rate of about 3500 to 4500 feet per minute. This will give an aircraft, cruising at 35,000 feet about 10 minutes to fly a distance of about 40 to 50 nautical miles. Remember, pilots have been trained to restart/relight the engines whenever they encounter total engine failures. If restarting the engines were unsuccessful, they would have no choice but to carry out a prepared forced landing - just like what the Canadian pilot did to the crippled Boeing 767.

What happens when all engines fail

At the rate of decent you mentioned. 3500 to 4500 feet per minute. How does that look when it comes into contact with the earth's surface ? Catastrophic ?

The rate of descent is not catastrophic alone. The vertical speed component is only 45 or 50 mph ( about 41 knots). However, there is still a horizontal speed component of probably about 230 to 260 mph ( about 210 knots). Without doing the math to figure out the g-force components, I can say that yes it would be quite catastrophic. Think about driving your car and hitting a concrete wall at 45 mph while simultaneously being sideswiped by a train doing 240 mph.

[khaosai]

Khaosai - Since the hydraulic pumps are connected to the core of the turbine,baca use of wind milling I assume you will have some slow hydraulics. I believe 777 is still steel cable from yoke to servo, so should still work

Tywais - if all dead and just on autopilot, I think it would go into a spin either on single engine ops, or when second fail due to rudder and aileron inputs .... Khaosai should be able to confirm if single engine can still be handled by auto pilot.....

As such - looks like a nice smooth landing

Sent from my iPad using ThaiVisa app

Hi,

The left and right hydraulic systems each have a primary engine drive pump and electrically driven demand pumps. The demand pumps act as a back up to the engine driven pump and also operate due to high system demand. Would windmilling provide some limited system pressure. Possibly, I don't know to be honest. With the dual engine failure scenario the ram air turbine provides centre system hydraulic power to the primary flight control components.

The B777 flight control system is electrically operated. If in the unlikely event of a complete electrical failure then the cables from the flight deck to the stabiliser and a few spoiler panels will enable the pilot to maintain straight and level flight until electrical power is re established.

If one engine flamed out at high level then the thrust asymmetry compensation will apply rudder to maintain the aircraft in balance. The only problem with this situation is that pilot input is required to enable the aircraft to descend to a lower, safer more manageable altitude. That is a very straightforward thing to achieve.

With no pilot input available to enable the aircraft to descend then the aircraft will rely on the flight envelope protection.

First off the auto throttle will "wake up" and increase thrust to avoid getting too slow. If that is not enough, and it won't be at high altitude, then the aircraft will get to the point of stall and then start a controlled descent, maintaining a safe speed to prevent a further stall. Normally pilot input would hopefully have occurred before both of these occur. If no pilot input then the aircraft will continue until impact with the ground.

With a dual engine failure then you have no auto pilot and no flight envelope protection.

[khaosai]

Your question was, when an airplane encounters all engines failure, does the plane start flipping and crash, or continue to fly while losing height? If it continues to fly, how long does it last and how safe it is to land the aircraft ?

As I have described earlier, the aircraft does not flip or crash. It continues to fly at an optimum gliding speed, a speed much lower than its cruising speed.

However, it may not be able to maintain its cruising altitude but continues to lose height at a rate of about 3500 to 4500 feet per minute. This will give an aircraft, cruising at 35,000 feet about 10 minutes to fly a distance of about 40 to 50 nautical miles. Remember, pilots have been trained to restart/relight the engines whenever they encounter total engine failures. If restarting the engines were unsuccessful, they would have no choice but to carry out a prepared forced landing - just like what the Canadian pilot did to the crippled Boeing 767.

What happens when all engines fail

At the rate of decent you mentioned. 3500 to 4500 feet per minute. How does that look when it comes into contact with the earth's surface ? Catastrophic ?

The rate of descent is not catastrophic alone. The vertical speed component is only 45 or 50 mph ( about 41 knots). However, there is still a horizontal speed component of probably about 230 to 260 mph ( about 210 knots). Without doing the math to figure out the g-force components, I can say that yes it would be quite catastrophic. Think about driving your car and hitting a concrete wall at 45 mph while simultaneously being sideswiped by a train doing 240 mph.

That rate of descent would not be pretty and as you said would be catastrophic. A hard landing is normally defined as a descent rate of 600ft per minute or more.

[balo]

I wonder if they will find the plane when I'm still alive ?

I would hate to die without knowing the truth about this big mystery.

[hawker9000]

Your question was, when an airplane encounters all engines failure, does the plane start flipping and crash, or continue to fly while losing height? If it continues to fly, how long does it last and how safe it is to land the aircraft ?

As I have described earlier, the aircraft does not flip or crash. It continues to fly at an optimum gliding speed, a speed much lower than its cruising speed.

However, it may not be able to maintain its cruising altitude but continues to lose height at a rate of about 3500 to 4500 feet per minute. This will give an aircraft, cruising at 35,000 feet about 10 minutes to fly a distance of about 40 to 50 nautical miles. Remember, pilots have been trained to restart/relight the engines whenever they encounter total engine failures. If restarting the engines were unsuccessful, they would have no choice but to carry out a prepared forced landing - just like what the Canadian pilot did to the crippled Boeing 767.

What happens when all engines fail

At the rate of decent you mentioned. 3500 to 4500 feet per minute. How does that look when it comes into contact with the earth's surface ? Catastrophic ?

The rate of descent is not catastrophic alone. The vertical speed component is only 45 or 50 mph ( about 41 knots). However, there is still a horizontal speed component of probably about 230 to 260 mph ( about 210 knots). Without doing the math to figure out the g-force components, I can say that yes it would be quite catastrophic. Think about driving your car and hitting a concrete wall at 45 mph while simultaneously being sideswiped by a train doing 240 mph.

That rate of descent would not be pretty and as you said would be catastrophic. A hard landing is normally defined as a descent rate of 600ft per minute or more.

600fpm? Really? 'Seems high. Would think touching down at even near that rate would do normal aircraft some definite damage.

[tigermonkey]

Khaosai - Since the hydraulic pumps are connected to the core of the turbine,baca use of wind milling I assume you will have some slow hydraulics. I believe 777 is still steel cable from yoke to servo, so should still work

Tywais - if all dead and just on autopilot, I think it would go into a spin either on single engine ops, or when second fail due to rudder and aileron inputs .... Khaosai should be able to confirm if single engine can still be handled by auto pilot.....

As such - looks like a nice smooth landing

Sent from my iPad using ThaiVisa app

Hi,

The left and right hydraulic systems each have a primary engine drive pump and electrically driven demand pumps. The demand pumps act as a back up to the engine driven pump and also operate due to high system demand. Would windmilling provide some limited system pressure. Possibly, I don't know to be honest. With the dual engine failure scenario the ram air turbine provides centre system hydraulic power to the primary flight control components.

The B777 flight control system is electrically operated. If in the unlikely event of a complete electrical failure then the cables from the flight deck to the stabiliser and a few spoiler panels will enable the pilot to maintain straight and level flight until electrical power is re established.

If one engine flamed out at high level then the thrust asymmetry compensation will apply rudder to maintain the aircraft in balance. The only problem with this situation is that pilot input is required to enable the aircraft to descend to a lower, safer more manageable altitude. That is a very straightforward thing to achieve.

With no pilot input available to enable the aircraft to descend then the aircraft will rely on the flight envelope protection.

First off the auto throttle will "wake up" and increase thrust to avoid getting too slow. If that is not enough, and it won't be at high altitude, then the aircraft will get to the point of stall and then start a controlled descent, maintaining a safe speed to prevent a further stall. Normally pilot input would hopefully have occurred before both of these occur. If no pilot input then the aircraft will continue until impact with the ground.

With a dual engine failure then you have no auto pilot and no flight envelope protection.

I don't know if you or others have the answer to this.Something like 5 years ago a T7 driver was talking to me about TAC, and said that often with an engine failure/flame-out the TAC would shut down and need to be recycled. Apparently, TAC relies on thrust comparisons between the 2 engines, cutting in at 10% differential, but with a complete engine failure, the initial engines parameters after failure are often invalid, causing the TAC to shut down. My question is whether this TAC shut down causes the TAC switch on the flight deck to move to "off", or whether the TAC itself initiates a restart/recycle. If it is the former, and there is no active pilot to press TAC "on", the single engine shut down could immediately become catastrophic.

I should have paid more attention to my friends discussion !

[khaosai]

Khaosai - Since the hydraulic pumps are connected to the core of the turbine,baca use of wind milling I assume you will have some slow hydraulics. I believe 777 is still steel cable from yoke to servo, so should still work

Tywais - if all dead and just on autopilot, I think it would go into a spin either on single engine ops, or when second fail due to rudder and aileron inputs .... Khaosai should be able to confirm if single engine can still be handled by auto pilot.....

As such - looks like a nice smooth landing

Sent from my iPad using ThaiVisa app

Hi,

The left and right hydraulic systems each have a primary engine drive pump and electrically driven demand pumps. The demand pumps act as a back up to the engine driven pump and also operate due to high system demand. Would windmilling provide some limited system pressure. Possibly, I don't know to be honest. With the dual engine failure scenario the ram air turbine provides centre system hydraulic power to the primary flight control components.

The B777 flight control system is electrically operated. If in the unlikely event of a complete electrical failure then the cables from the flight deck to the stabiliser and a few spoiler panels will enable the pilot to maintain straight and level flight until electrical power is re established.

If one engine flamed out at high level then the thrust asymmetry compensation will apply rudder to maintain the aircraft in balance. The only problem with this situation is that pilot input is required to enable the aircraft to descend to a lower, safer more manageable altitude. That is a very straightforward thing to achieve.

With no pilot input available to enable the aircraft to descend then the aircraft will rely on the flight envelope protection.

First off the auto throttle will "wake up" and increase thrust to avoid getting too slow. If that is not enough, and it won't be at high altitude, then the aircraft will get to the point of stall and then start a controlled descent, maintaining a safe speed to prevent a further stall. Normally pilot input would hopefully have occurred before both of these occur. If no pilot input then the aircraft will continue until impact with the ground.

With a dual engine failure then you have no auto pilot and no flight envelope protection.

I don't know if you or others have the answer to this.Something like 5 years ago a T7 driver was talking to me about TAC, and said that often with an engine failure/flame-out the TAC would shut down and need to be recycled. Apparently, TAC relies on thrust comparisons between the 2 engines, cutting in at 10% differential, but with a complete engine failure, the initial engines parameters after failure are often invalid, causing the TAC to shut down. My question is whether this TAC shut down causes the TAC switch on the flight deck to move to "off", or whether the TAC itself initiates a restart/recycle. If it is the former, and there is no active pilot to press TAC "on", the single engine shut down could immediately become catastrophic.

I should have paid more attention to my friends discussion !

Hi,

This switch does not go to the off position automatically, however the system will automatically disconnect.

The aircraft crew alerting system will indicate that it is no longer working. The crew then follow the check list guidance which ask you to switch it to the off position then back to the auto position to see if it can be reset.

If the message from the crew alerting system disappears then it's working again. If not then manual control inputs are required to compensate for an asymmetric situation.

[3NUMBAS]

http://www.bbc.co.uk/news/world-europe-27294407

quote

6 May 2014 Last updated at 12:43

Missing flight MH370: Europe to tighten black box rules

Europe's aviation watchdog has announced new proposals to make it easier to find flight recorders, known as black boxes, from missing planes.

The plans include extending the transmission time of underwater locating devices fitted on the black boxes from 30 to 90 days.

The move comes in response to the disappearance of Malaysia Airlines flight MH370 on 8 March.

The plane vanished en route to Beijing, with 239 people on board.

The aircraft lost contact with air traffic controllers over the South China Sea, some seven hours after it took off from Kuala Lumpur.

Officials now believe, based on satellite data, that it ended its journey in the sea far west of the Australian city of Perth.

It is not yet known what caused the plane to fly so far off course. Finding its "black box" flight recorders is seen as key to understanding what happened.

'Tragic flight'

As part of the measures, the European Aviation Safety Agency (EASA) said large aeroplanes flying over oceans should be equipped with a new pinger frequency, making it easier to locate the recording devices under water.

In addition, the minimum recording duration of cockpit voice recorders installed on new planes should be increased from two to 20 hours.

"The tragic flight of Malaysia Airlines MH370 demonstrates that safety can never be taken for granted," EASA director Patrick Ky said in a statement on Tuesday.

"The proposed changes are expected to increase safety by facilitating the recovery of information by safety investigation authorities."

So far, an intensive search operation has found no sign of flight MH370.

Officials from Australia, Malaysia and China are meeting in the Australian capital, Canberra, this week to discuss the next stage in the operation.

Australian Deputy Prime Minister Warren Truss said new sonar and submersible equipment would be needed to scour a large area of ocean floor.

An initial search of the area where acoustic signals thought to be from flight recorders were heard found nothing.

On Wednesday, experts are due to share all the information, including satellite data, collected to date, at the talks in Canberra.

Australia has warned that the next stage of the search could take up to a year.

[P45Mustang]

The plans include extending the transmission time of underwater locating devices fitted on the black boxes from 30 to 90 days.

How's about making it a bit easier and extending it to 91 days?

Does the technology not exist for a black box to be fitted with kit that can communicate it's exact location?

Audible 'pings' seem a little analog and dated.

[Tywais]

The plans include extending the transmission time of underwater locating devices fitted on the black boxes from 30 to 90 days.

How's about making it a bit easier and extending it to 91 days?

Does the technology not exist for a black box to be fitted with kit that can communicate it's exact location?

Audible 'pings' seem a little analog and dated.

Frequency is an important factor in locating items under water. The higher the frequency and/or higher the conductivity the higher the attenuation of the signals. So low frequency analog is a necessity. Also at those low frequencies bandwidth is highly limited so not a lot of data can be sent.

ATTENUATION

Attenuation of radio waves in water (and, in fact, in any conducting medium) increases both with increase in conductivity

and increase in frequency. It can be calculated from the follow formula:

Attenuation (α) in dB/metre = 0. 0173 √(fσ)

where f = frequency in hertz

and σ = conductivity in mhos/metre

Figure 1 illustrates attenuation as a function of frequency for sea water and Adelaide water. Attenuation in sea water is

very high and to communicate at any depth at all, it is necessary to use very low frequencies (10 to 30 kHz) where

attenuation is in the order of 3.5 to 5 dB per metre. Operation in the lowest frequency amateur band (1.8 MHz) is out of

the question at 46 dB per metre.

Source in PDF

[P45Mustang]

The plans include extending the transmission time of underwater locating devices fitted on the black boxes from 30 to 90 days.

How's about making it a bit easier and extending it to 91 days?

Does the technology not exist for a black box to be fitted with kit that can communicate it's exact location?

Audible 'pings' seem a little analog and dated.

Frequency is an important factor in locating items under water. The higher the frequency and/or higher the conductivity the higher the attenuation of the signals. So low frequency analog is a necessity. Also at those low frequencies bandwidth is highly limited so not a lot of data can be sent.

ATTENUATION

Attenuation of radio waves in water (and, in fact, in any conducting medium) increases both with increase in conductivity

and increase in frequency. It can be calculated from the follow formula:

Attenuation (α) in dB/metre = 0. 0173 √(fσ)

where f = frequency in hertz

and σ = conductivity in mhos/metre

Figure 1 illustrates attenuation as a function of frequency for sea water and Adelaide water. Attenuation in sea water is

very high and to communicate at any depth at all, it is necessary to use very low frequencies (10 to 30 kHz) where

attenuation is in the order of 3.5 to 5 dB per metre. Operation in the lowest frequency amateur band (1.8 MHz) is out of

the question at 46 dB per metre.

Source in PDF

Understood.

Thanks.

Better tracking of flight paths whilst airplanes are still airborne would appear to be a way forward.

That technology must surely be achievable?

I cannot believe that in this day and age that a 777 can 'disappear' and the only information available comes from an Inmarsat communications satellite not designed for the purpose.

If my iPad gets lost, its location can be traced !

Not possible with a Boeing777?

[canuckamuck]

Have someone smash your Ipad and toss it in the ocean, and then try to find it.

But I do do think much more could be done in the way of beacons. Having a few floating devices that jettison like an airbag on impact, or on command, that phone home by sat phone until they are found is one possibility.