Flex TO computation

[kevkev 1]

Since TOPCAT is not currently supporting the 777, what tools can be used to optimize flex TO ?

 

Kevkev

[3-2-1-Now 126]

My suggestion: don't use it. The accident at Sydney with the A340 is sobering reading, and just highlights why FLEX is bad news. OK - so they saved a bit of wear on a few engines, only to have serious damage, and near loss of life because of it. "The risk is too damn high!".

 

http://www.skybrary.aero/bookshelf/books/1748.pdf‎

 

Interesting reading.

 

To answer your question though, if they supply the same level of manuals as they did for the NGX, then you will have all the tables necessary to compute FLEX takeoff reduction (if you have the NGX, look in Volume 1, PI.50.29 and PI.50.44, PDF pages 955 and 970).

 

Best regards,

Robin.

[crazy voyager 13]

My suggestion: don't use it. The accident at Sydney with the A340 is sobering reading, and just highlights why FLEX is bad news. OK - so they saved a bit of wear on a few engines, only to have serious damage, and near loss of life because of it. "The risk is too damn high!".

 

http://www.skybrary.aero/bookshelf/books/1748.pdf‎

 

Interesting reading.

 

To answer your question though, if they supply the same level of manuals as they did for the NGX, then you will have all the tables necessary to compute FLEX takeoff reduction (if you have the NGX, look in Volume 1, PI.50.29 and PI.50.44, PDF pages 955 and 970).

 

Best regards,

Robin.

 

I've only read the conclusion but to say "don't use flex" based on data entry error is not the conclusion I would draw.

 

Data entry error can occur regardless of flex temp being used or not, the fact is thousands of flights use flex without any issues. Also to stop using flex temp would not eliminate the data entry problem, it would however increase costs for a very minimal safety increase. It would also increase noise pollution which is something the aviation industry has worked very hard to reduce.

[scandinavian13 5,192]

Also:

Not FLEX.  Flex is the Airbus term.  It's assumed temperature (ATM) in the Boeing.  There's fixed derate (TO/TO1/TO2), and reduced thrust (assumed temp).

[3-2-1-Now 126]

LOL - I can hardly hear ANY commercial aircraft (turboprop or jet) fly over my house, yet it doesn't stop my neighbor having a too loud exhaust on his car that I can hear 3 miles away (no kidding).

 

Noise from aircraft is out of proportion with the noise Boy Racer can make. I'm not impressed.

 

Best regards,

Robin.

Also:

Not FLEX.  Flex is the Airbus term.  It's assumed temperature (ATM) in the Boeing.  There's fixed derate (TO/TO1/TO2), and reduced thrust (assumed temp).

 

Thanks for the correction.

 

Hmm.... thinking about that acronym... Automated Teller Machine = $$$. Using ATM instead of TOGA saves $$$? Is that what Boeing were thinking when they came up with that?

 

Best regards,

Robin.

[scandinavian13 5,192]

 

 

Hmm.... thinking about that acronym... Automated Teller Machine = $$$. Using ATM instead of TOGA saves $$$? Is that what Boeing were thinking when they came up with that?

 

I think it's Assumed TeMperature, to differentiate it and AT for Auto-Throttle.  I didn't run off into the manuals to figure out what it means precisely, however.

 

...but yes, you'll be saving money on engine costs, though not fuel.

[crazy voyager 13]

Stand underneath a departing B747 and you'll notice that it makes quite a racket

[kevkev 1]

Thanks for the replies.

The problem is that in the 777 FCOM I have, there are no tables for TO1 or TO2.

Such tables can be found in the FPPM but I only have the FPPM for the 200ER and not the 200LR.

Any idea where the data can be found ?

 

Kevkev

[3-2-1-Now 126]

Hopefully PMDG will include that data with the package.

 

Did you try SmartCockpit.com?

 

Best regards,

Robin.

[Kerlix 99]

 

 

Any idea where the data can be found ?

 

I don't believe anyone can post that here, per forum (possibly AVSIM) rules. I'll be waiting for PFPX. 

 

Though, this does make me curious.

 

Hey,

 

,

 

out of curiousity, what are the beta testers doing in this regard? I imagine these features are being used since, well, you're testers. Is it a "wing it within reason" type of approach?

[scandinavian13 5,192]

 

 

Is it a "wing it within reason" type of approach?

 

Currently, that is my approach, yes.

[Noble. 142]

My suggestion: don't use it. The accident at Sydney with the A340 is sobering reading, and just highlights why FLEX is bad news. OK - so they saved a bit of wear on a few engines, only to have serious damage, and near loss of life because of it. "The risk is too damn high!".

 

http://www.skybrary.aero/bookshelf/books/1748.pdf‎

 

Interesting reading.

 

To answer your question though, if they supply the same level of manuals as they did for the NGX, then you will have all the tables necessary to compute FLEX takeoff reduction (if you have the NGX, look in Volume 1, PI.50.29 and PI.50.44, PDF pages 955 and 970).

 

Best regards,

Robin.

 

That incident had nothing to do with de-rating being dangerous and everything to do with the fact they punched in the wrong weights on the computer and it wasn't double checked. It should be common sense to pilots on an aircraft they've flown for years that if you're taking off anywhere near the MTOW and the computer is giving you a high FLEX temp (and low vspeeds/small difference between V1/VR) - something has probably gone wrong, especially given that the runways at YSSY are not unusually long (longest is 4000m), so pretty standard for the major international airports.

 

I think it's a bit silly to recommend people "don't use it" just because an incident exists where pilots didn't have the common sense to realise something was up, or the common decency to make sure they don't punch in a TOW that is 100 tonnes less than their actual weight. 

[3-2-1-Now 126]

@Noble: did you actually read the report? Do you know why the tail strike actually occurred? Do you know why they did NOT go through the ILS antenna that was waiting to shred the aircraft into a million pieces at the end of the runway?

 

Answer these questions, and you'll know why I'm not a fan of FLEX/ATM.

 

Best regards,

Robin.

[Noble. 142]

@Noble: did you actually read the report? Do you know why the tail strike actually occurred? Do you know why they did NOT go through the ILS antenna that was waiting to shred the aircraft into a million pieces at the end of the runway?

 

Best regards,

Robin.

 

What is the point of your questions here? The entire event occurred because they input a weight 100 tonnes less than their actual weight - that's the problem. The only reason the flight didn't end in complete disaster is because the captain did the logical thing and put the aircraft into TOGA when he realised something was up, i.e. he was doing his job. Of course there's going to be massive issues with using de-rate/flex/assumed temp if pilots aren't going to be careful about the data they put in, and it's not like it's the only area of their job that requires accurate data input and double checking, it should be second nature. 

[Kerlix 99]

 

 

I think it's a bit silly to recommend people "don't use it" just because an incident exists where pilots didn't have the common sense to realise something was up, or the common decency to make sure they don't punch in a TOW that is 100 tonnes less than their actual weight. 

 

 

I agree. Completely.

 

By that same logic, you might get food poisoning, hit by bus, in a car accident or have an asthma attack walking up stairs so you'd better not get out of bed.