Ask a Pilot anything....

[IforB]

Brother D said:

WilliamWoollard said:

How much of the engines available power is used for a typical take off of a jet liner?

Depends - once you enter all the variables, weight, air pressure (pressure altitude), temp, runway length, runway condition and a few other bits into the FMS, it will give you an answer as to the flex/power used, so as to give the correct safety margin vs least engine wear.

Recently took a flight where the take off was a bit concerning as the acceleration was comparable to that of a wheezy bus, and it has gone wrong a couple of times in the past - https://aviation-safety.net/database/record.php?id...

PHL has a runway that is over 10,000 ft long and is virtually at sea-level. Alright it gets warm, but no need for a full bore take-off! That accident was a very, very badly handled rejected take-off rather than an over-run.

[JuniorD]

Brother D said:

WilliamWoollard said:

How much of the engines available power is used for a typical take off of a jet liner?

Depends - once you enter all the variables, weight, air pressure (pressure altitude), temp, runway length, runway condition and a few other bits into the FMS, it will give you an answer as to the flex/power used, so as to give the correct safety margin vs least engine wear.

Recently took a flight where the take off was a bit concerning as the acceleration was comparable to that of a wheezy bus, and it has gone wrong a couple of times in the past - https://aviation-safety.net/database/record.php?id...

Sure why use a calculated N1 of 93.3% when 81.5% will do it

http://avherald.com/h?article=4ac18a5b

[HoHoHo]

Brother D said:

WilliamWoollard said:

How much of the engines available power is used for a typical take off of a jet liner?

Depends - once you enter all the variables, weight, air pressure (pressure altitude), temp, runway length, runway condition and a few other bits into the FMS, it will give you an answer as to the flex/power used, so as to give the correct safety margin vs least engine wear.

Recently took a flight where the take off was a bit concerning as the acceleration was comparable to that of a wheezy bus, and it has gone wrong a couple of times in the past - https://aviation-safety.net/database/record.php?id...

Please bear in mind I'm not a pilot!

As Brother D mentioned it's all about facts and figures, temperature, altitude or whatever.

One story that springs to mind on use of power relates to an Emirates 777 taking off in Australia where a young FO input 262 tonnes weight rather than 362 tonnes into the flight computer. The computer calculated a thrust that was too low which in turn didn't generate sufficient speed. I believe the aircraft did get airborne however became very close to becoming a statistic - one incorrect digit was all it took

So, my question is - should these figures have been cross-checked on that flight or as a result of this very close call are these figures now cross-checked?

[wolfracesonic]

One for Ifor, Ginetta and the other contributing pilots I guess; what do you think happened to MH 370 and do you think it will turn up before the OP of this thread?

[IforB]

wolfracesonic said:

One for Ifor, Ginetta and the other contributing pilots I guess; what do you think happened to MH 370 and do you think it will turn up before the OP of this thread?

No idea what happened to MH370, but I know a bit about the new search being launched for by Ocean Infinity and with the capability they are deploying, then they've got a chance of finding it.

Not sure if it's soon enough though!

[Brother D]

HoHoHo said:

Please bear in mind I'm not a pilot!

As Brother D mentioned it's all about facts and figures, temperature, altitude or whatever.

One story that springs to mind on use of power relates to an Emirates 777 taking off in Australia where a young FO input 262 tonnes weight rather than 362 tonnes into the flight computer. The computer calculated a thrust that was too low which in turn didn't generate sufficient speed. I believe the aircraft did get airborne however became very close to becoming a statistic - one incorrect digit was all it took

So, my question is - should these figures have been cross-checked on that flight or as a result of this very close call are these figures now cross-checked?

Yes - that one is good illustration - https://aviation-safety.net/database/record.php?id...

[dave_s13]

No such thing as a stupid question but....

Can turbulence ever be severe enough to terminally damage a large aircraft.

Is it even physically possible for me to be on my way to Spain happily sipping on a miniature size can of Amstel one minutes and the next be sucked out into the frozen void that is cruising altitude wishing I'd gone to butlins?

[WinstonWolf]

We had the drinks trolleys floating above the aisle during a particularly bad bout of clear air turbulence. The crew all dropped to the floor and braced against the seats

That was proper hairy...

[JuniorD]

dave_s13 said:

No such thing as a stupid question but....

Can turbulence ever be severe enough to terminally damage a large aircraft.

Is it even physically possible for me to be on my way to Spain happily sipping on a miniature size can of Amstel one minutes and the next be sucked out into the frozen void that is cruising altitude wishing I'd gone to butlins?

Re turbulence - no, turbulence won't be bad enough to terminally damage a large aircraft. Certainly not the type of clear air turbulence you'd get on during the cruise phase of your regular flight.

Terminal damage to a large aircraft as an indirect result of the likes of wake turbulence is a remote possibility, take for example the A300 that crashed in Queens, NY after the copilot unnecessarily overdid it on the rudder in response to wake turbulence, causing the vertical stabiliser to break off. However the cause of the crash in this case was not the wake turbulence per se (which could have been ridden out), but rather the copilot's actions.

There are plenty of cases where wake turbulence has directly caused aircraft (usually smaller ones, but also the lines of DC9 and Hercules) to crash.

[99dndd]

WinstonWolf said:

We had the drinks trolleys floating above the aisle during a particularly bad bout of clear air turbulence. The crew all dropped to the floor and braced against the seats

That was proper hairy...

I imagine the trolley was needed when that calmed down

[IforB]

JuniorD said:

dave_s13 said:

No such thing as a stupid question but....

Can turbulence ever be severe enough to terminally damage a large aircraft.

Is it even physically possible for me to be on my way to Spain happily sipping on a miniature size can of Amstel one minutes and the next be sucked out into the frozen void that is cruising altitude wishing I'd gone to butlins?

Re turbulence - no, turbulence won't be bad enough to terminally damage a large aircraft. Certainly not the type of clear air turbulence you'd get on during the cruise phase of your regular flight.

Terminal damage to a large aircraft as an indirect result of the likes of wake turbulence is a remote possibility, take for example the A300 that crashed in Queens, NY after the copilot unnecessarily overdid it on the rudder in response to wake turbulence, causing the vertical stabiliser to break off. However the cause of the crash in this case was not the wake turbulence per se (which could have been ridden out), but rather the copilot's actions.

There are plenty of cases where wake turbulence has directly caused aircraft (usually smaller ones, but also the lines of DC9 and Hercules) to crash.

I'd disagree with that. There is the case of BOAC flight 911 which crashed near Mount Fuji in 1966. The aircraft was a Boeing 707 and the suspected cause of the crash was turbulence from Mount Fuji which forced the aircraft into a manoeuvre that simply ripped the thing apart. That's the official line though and there is suspicion that it may have been caused by cracks to the fin mounting bolts which was seen across the fleet, but that is very much tin-foil hat supposition on the part of some.

Turbulence is highly unlikely to cause a structural failure, but get caught in something like a dissipating mountain wave and you could encounter severe or extreme turbulence forms, so it is possible.

[motomk]

HoHoHo said:

One story that springs to mind on use of power relates to an Emirates 777 taking off in Australia where a young FO input 262 tonnes weight rather than 362 tonnes into the flight computer.

A340-500 Had to fly home a few months later at 10,000ft after emergency surgery.

[JuniorD]

IforB said:

JuniorD said:

dave_s13 said:

No such thing as a stupid question but....

Can turbulence ever be severe enough to terminally damage a large aircraft.

Is it even physically possible for me to be on my way to Spain happily sipping on a miniature size can of Amstel one minutes and the next be sucked out into the frozen void that is cruising altitude wishing I'd gone to butlins?

Re turbulence - no, turbulence won't be bad enough to terminally damage a large aircraft. Certainly not the type of clear air turbulence you'd get on during the cruise phase of your regular flight.

Terminal damage to a large aircraft as an indirect result of the likes of wake turbulence is a remote possibility, take for example the A300 that crashed in Queens, NY after the copilot unnecessarily overdid it on the rudder in response to wake turbulence, causing the vertical stabiliser to break off. However the cause of the crash in this case was not the wake turbulence per se (which could have been ridden out), but rather the copilot's actions.

There are plenty of cases where wake turbulence has directly caused aircraft (usually smaller ones, but also the lines of DC9 and Hercules) to crash.

I'd disagree with that. There is the case of BOAC flight 911 which crashed near Mount Fuji in 1966. The aircraft was a Boeing 707 and the suspected cause of the crash was turbulence from Mount Fuji which forced the aircraft into a manoeuvre that simply ripped the thing apart. That's the official line though and there is suspicion that it may have been caused by cracks to the fin mounting bolts which was seen across the fleet, but that is very much tin-foil hat supposition on the part of some.

Turbulence is highly unlikely to cause a structural failure, but get caught in something like a dissipating mountain wave and you could encounter severe or extreme turbulence forms, so it is possible.

Hopefully not in the cruise, though maybe on the way to/from Spain some prayers around the Pyrenees may indeed be worthwhile.

Meanwhile, there goes our tail



https://www.youtube.com/watch?v=WJuEAQbxWRo

[juggsy]

As a Captain/FO, how often do you have to support the crew with unruly passengers and lay down the law? Have you every had to divert as a result of someone being disruptive?

[Turn7]

WRT to turbulence, when it feels like th eplane drops about 200 feet and I think IM go to die, just how far does the plane actually drop ?

[WinstonWolf]

99dndd said:

WinstonWolf said:

We had the drinks trolleys floating above the aisle during a particularly bad bout of clear air turbulence. The crew all dropped to the floor and braced against the seats

That was proper hairy...

I imagine the trolley was needed when that calmed down

Most of the wine ended up on the bulkhead, my mrs at the time had to hold our daughter down as the bassinet she was in was also floating

[HoHoHo]

motomk said:

HoHoHo said:

One story that springs to mind on use of power relates to an Emirates 777 taking off in Australia where a young FO input 262 tonnes weight rather than 362 tonnes into the flight computer.

A340-500 Had to fly home a few months later at 10,000ft after emergency surgery.

Accepted however the press (and air crash whatsit on satellite TV) are both incorrect with their type of aircraft!

[Ginetta G15 Girl]

JuniorD said:

Re turbulence - no, turbulence won't be bad enough to terminally damage a large aircraft. Certainly not the type of clear air turbulence you'd get on during the cruise phase of your regular flight.

CAT (Clear Air Turbulence) no but Cb (CumuloNimbus Cloud) associated turbulence swatted an Kuwaiti C-130 out of the sky over Southern France.

WRT Wake Turbulence, we ended up at more than 90 degrees of bank fairly close to the ground following a 757 into Aldergrove (ATC hadn't ensured the correct seperation).

[JuniorD]

Ginetta G15 Girl said:

JuniorD said:

Re turbulence - no, turbulence won't be bad enough to terminally damage a large aircraft. Certainly not the type of clear air turbulence you'd get on during the cruise phase of your regular flight.

CAT (Clear Air Turbulence) no but Cb (CumuloNimbus Cloud) associated turbulence swatted an Kuwaiti C-130 out of the sky over Southern France.

WRT Wake Turbulence, we ended up at more than 90 degrees of bank fairly close to the ground following a 757 into Aldergrove (ATC hadn't ensured the correct seperation).

Yikes.

Which brings me to another question:

Has anyone here been involved in an incident that was investigated by the CAA or other authority, or any incident that got a mention & discussion on AV Herald or the likes?

[dave_s13]

Ginetta G15 Girl said:

CAT (Clear Air Turbulence) can seriously fk your holidays

You could've just lied.