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toung
9th Jun 2019, 16:37
https://www.pprune.org/tech-log/609196-eng-out-accel-height.html

Hi I am B777 captain .
According to this topic I have told my fleet by safety report but they still confirmed that 400ft engine out flaps retraction height is practicable in almost airport as stated in takeoff analysis table(we have no OPT so we need to check with Take off analysis table which called gross weight chart). I ask for 800 or 1000 ft instead of 400 but they said the TOGA time limit 5 mins may be exceeded
By the way I wanna ask you for some questions.
Is there any of you have used 400ft in majority for eng out flaps retraction height and what is your TOGA time limit?
My fleet policy have been changed from original of Boeing FCTM to initiate “memory items” at 500ft instead of 400ft as Boeing said.
I wonder that in case of eng fail and fire at v1 and continue , if i have follow my fleet policy it seems scaring to accel the aircraft first at 400ft and leave fire to continue and when reaching 500ft to start memory items checklist and do it both in the same time ( accel + memory items).
I really need your comments or recommendation.
Will be appreciated
Thank so much but I have no idea.

gearlever
9th Jun 2019, 16:58
- below 400ft in an OEI case we do NOTHING, beside raising the gear, passing 400ft: Start Procedure
- OEI acc height in my outfit is 1.500 ft unless local procedures differ

toung
9th Jun 2019, 17:01
Dear pls let me know what is your aircraft type / TOGA time limit also.

gearlever
9th Jun 2019, 17:03
5 min by regulations....

Don't get me wrong, but are you a FltSim guy?

toung
9th Jun 2019, 17:07
5 min by regulations....

Don't get me wrong, but are you a FltSim guy?
lol, nope sir I am really B777 PIC
but some airline use 5mins for both eng and 10 mins for OEI
some are 5 mins both eng and 5 mins OEI same as my fleet.
This is an optional for airline upto amount of payment to certified

gearlever
9th Jun 2019, 17:14
Maybe this helps....

TOGA limit (https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC%2033-7.1.pdf)

toung
9th Jun 2019, 17:24
Maybe this helps....

TOGA limit (https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC%2033-7.1.pdf)

When requested by the applicant, the FAA may approve extension of the time limit for the rated takeoff power or thrust from 5 minutes to 10 minutes for an airplane operation when one engine becomes inoperative during takeoff

Sorry for unclear question so the revision is
What is OEI TOGA LIMIT for your fleet for me with no extension is just only 5 mins that is why my fleet said we have to accel at 400ft instead of 1000 or 1500 ft.

I wanna know is there any OEI TOGA LIMIT 5 mins like me and use 800 or 1000 for accel safely.

Tu.114
9th Jun 2019, 21:28
My fleet policy have been changed from original of Boeing FCTM to initiate “memory items” at 500ft instead of 400ft as Boeing said.
I wonder that in case of eng fail and fire at v1 and continue , if i have follow my fleet policy it seems scaring to accel the aircraft first at 400ft and leave fire to continue and when reaching 500ft to start memory items checklist and do it both in the same time ( accel + memory items).




Either I misunderstand you entirely here or there is a little confusion between memory items/abnormal checklist and acceleration to be read between the lines of your post... Now, my experience does not include the 777, but in all the types I know and have heard of, it is customary to first attack the malfunction and then, with a (basic) shutdown performed, at a suitable altitude accelerate and clean up the aircraft.

The suitable altitude of course depends on various conditions including the minimum acceleration altitude of 1000´ (on all the types I know), the general terrain situation in the area, the status of the initial checklist work and so on - it is generally determined in the takeoff performance calculation, be it via paper tables or via electronic means.

safelife
9th Jun 2019, 22:23
Most jet aircraft will fly at least like 120 kt especially when heavy.
By regulation you're required to obtain a 2.4% climb gradient.
Doing that for five minutes will make you climb at least 1500 ft.
Hence you cannot be TOGA-time-limited lower than that.

tomuchwork
9th Jun 2019, 23:02
In 5 mins you easily climb to 1000ft(which most companies use, at least the ones I worked for, some being (former) major players in the aviation world) before acc. A few even go up to 1500ft which is no harm. 400 ft is a bit low and more importantly, has a big risk of rushing things where nothing should be rushed(memory items, call ATC, in your case, start acc and cleanup - sounds all a bit messy).

So - you are saying that the clever guys in the office of your company made memory items at 500 ft but start acc at 400 ft? Did I get that right? And I always thought our SOP guys in my outfit are "special"(let's be nice today) that make life in busy moments unnecessary complicated....but acc in 400ft....impressive.

For example: We do nothing up to 400 ft except raising gear(with positive rate blablabla), cancel any warnings. 400ft ensure HDG Sel(Or LNAV if suitable), tune radios for missed approach(Single engine procedure), Memory items if required. At MFRA(usually 1000ft except OPT tells us different), bug up, retract, flaps up level change, MCT, climb MSA. Never takes more than 5 mins(and we fly less sophisticated Boeing planes than a 777).

FullWings
9th Jun 2019, 23:04
What those guys said ^^^^

If 800 or 1,000’AAL takes more than five minutes OEI in a twin like the 777, then you’ve got bigger problems than you think...

We use 1,000'AAL as standard (777-200 and -300), sometimes higher with terrain-constrained ops but never lower. No problems with TOGA limits.

FlyingStone
9th Jun 2019, 23:40
Most jet aircraft will fly at least like 120 kt especially when heavy.
By regulation you're required to
Doing that for five minutes will make you climb at least 1500 ft.
Hence you cannot be TOGA-time-limited lower than that.

There is a misunderstanding on this thread that if you are able to climb to your MFRA within 5 minutes, you are not limited by 5-minute limit. In fact, the net takeoff flight path calls for TOGA thrust to remain set until the flaps are fully retracted and final takeoff speed (Vfto) achieved. Only then can MCT normally be set.

Obviously one might hit this limit earlier, especially during extended 2nd segment (higher than standard MFRA), so part of the 3rd segment would have to be flown with MCT already. Performance software would have to compensate for that, as acceleration and thus flap retraction would be slower with MCT compared to TOGA, and 3rd segment would be extended as well.

Additionally, while Boeing says memory items are typically accomplished at 400ft, this is not a rule. And when using MFRA at 400ft, it is probably safer to start acceleration first (to assure obstacle clearance) and complete memory items as workload allows during flap retraction. Not ideal, but certainly doable.

Hi I am B777 captain .
According to this topic I have told my fleet by safety report but they still confirmed that 400ft engine out flaps retraction height is practicable in almost airport as stated in takeoff analysis table(we have no OPT so we need to check with Take off analysis table which called gross weight chart). I ask for 800 or 1000 ft instead of 400 but they said the TOGA time limit 5 mins may be exceeded

Would you please enlighten us which B777 operator on this lovely planet is operating their multi-hundred million dollars worth widebody aircraft and is too cheap to fork out couple of quid for OPT to Boeing in 2019? And at the same time uses 400ft MFRA as a default for their RTOW charts?

This has to be madness, surely. It’s one thing to use such low MFRA to maximize payload when/if required, but to use it on every single departure is insane.

For example: We do nothing up to 400 ft except raising gear(with positive rate blablabla), cancel any warnings. 400ft ensure HDG Sel(Or LNAV if suitable), tune radios for missed approach(Single engine procedure), Memory items if required. At MFRA(usually 1000ft except OPT tells us different), bug up, retract, flaps up level change, MCT, climb MSA. Never takes more than 5 mins(and we fly less sophisticated Boeing planes than a 777)

I don’t know where you operate, but with takeoffs close to edges of environmental envelope (hot and high), you are normally limited by 5/10-minute takeoff thrust limit.

tomuchwork
9th Jun 2019, 23:55
FlyingStone

I think if they can operate out of Madrid in summer it will be fine.... enough said I hope(of course there is always MORE hot, e.g. ME but at SL or it is higher but lower temperatures).

AS for the first part of your post - I think most of us know the definition of the 5 minutes limit. It is when you are able to set MCT(which happens at flaps up). Not in aviation since yesterday. I think the TO needs to clarify his company procedures a bit OR the defintion of certain manouvers he mentioned.

But rest assure - WE know the limit of our planes. At least I do. And again, 5 Minutes in 1000ft is NOT a problem. Being a bit aware of the performance of a 777 I doubt it would be worse as a 737NG.

As for the memory items/recall items depending on manufacturer - usually you do them at 400ft(Boeing, Airbus(A300), Bombardier) and later. Most operators use the manufacturers suggestions regarding memory items(as it is an important issue, obviously there was a reason to make them memory items).

But this is a useless discussion. I am sure we all know what we are talking about. But it surprises me(us!) that someone makes a cleanup(in a widebody!!) at 400ft.

Mach E Avelli
10th Jun 2019, 00:31
There is the theory, then there is the reality. Disclaimer - I am not familiar with the B777, only more “primitive” jets.
From countless simulator exercises, I have observed that if a fire is introduced at V1 with simultaneous loss of thrust (highly unlikely, I know, but possible) and pilots attempt to complete memory actions for the fire drill at 400 ft simultaneous with, or closely followed by, acceleration and clean up, it is almost certain that:
Some item in the fire drill will be overlooked, due to the distraction/interruption of the acceleration and clean up procedure, or:
Some item in the acceleration segment will be mishandled - typically flap speeds will be exceeded or final climb speed will not be established on schedule.
If the fire is NOT accompanied by a simultaneous loss of thrust (more probable) and pilots attempt to combine the memory actions with an early acceleration it gets rather exciting as the power is cut about half way through the third segment.
So, I advise crews to: deal with fire ASAP, as it is the thing trying to destroy the structure, but keep climbing until the memory actions have been completed, then accelerate and clean up. For less critical failures, accelerate, clean up and establish final climb at MCT then complete the appropriate failure drill.
400 ft acceleration to gain some payload seems ill advised. 1000ft is a safer choice and easier for pilots to compute when surprised by a failure. The performance analysis can be tweaked to whatever acceleration above the legal minimum the operator chooses, albeit in some cases with a small payload penalty. It is probably time the legislation reflected that. 400ft was established way back in time when large piston engines and early turbine engines had very low time limits on takeoff power compared with today’s engines.
As for five or ten minute engine limits, again nice in theory, and the performance analysis has to account for this. But, in practice, what would the consequences be if a time limit over-ran by a minute or so in the interests of getting the job done? An engine is unlikely to self destruct, though of course may require premature overhaul any time a limit is exceeded.
At tea and bickies with the Chief Pilot I would be asking whether the airline preferred an overhaul to a hull loss.

toung
10th Jun 2019, 01:41
Thanks for all replies.
Very impressive idea that I supposed to read.
I do agree with all of you but wanna make sure may I have some misunderstood or not that’s why I have posted this thread.
I will try to let some clever guys in my fleet rethink again about this threat opener.
But I am not sure this will be solved or not. If not.
After that what should I do?

FlyingStone
10th Jun 2019, 08:39
I think if they can operate out of Madrid in summer it will be fine.... enough said I hope(of course there is always MORE hot, e.g. ME but at SL or it is higher but lower temperatures).

Madrid is not really hot and high (2000ft is almost at SL). Try Johannesburg (5500ft,30C), Kabul (5800ft, 30C), Addis Ababa (7800ft, 25C) and a lot of other places. This is where you are normally limites with 5-min takeoff thrust.

MAD is normally obstacle limited anyway.

Skyjob
10th Jun 2019, 09:24
eng out flap retraction and the OEI time limit are separate from each other but can easily be used simultaneously.

The eng flap retraction is a company/operator set standard minimum at or above manufacturer typical recommended minimum, which can be adjusted to suit obstacle limited airports etc.

The OEI thrust limit is the limit that the company/operator has paid the manufacturer for to use the engine at maximum takeoff power, a slightly higher setting than MCT.
Note: if manufacturer offer the varying purchase in limits, the engine can sustain the upper limit, which is its design criteria, including safety margins on top; so if you need it and only have a lower limit, it could be there for use to avoid a CFIT or other life changing thrust dependent issues; not legal but just saying it's there and can be used...

FlightDetent
10th Jun 2019, 09:54
@toung I suggest to use the following two step method to convince your flight ops engineers into a higher ACC ALT

1) safelife's calculation (put your own time values as appropriate)
- a: I assume it takes 1 minute from setting the TO POWER to the start of the first segment (V2 + positive climb);
- b: then you will climb at no less than 2,4%, which is the regulatory minimum;
- c: I assume after reaching the EO ACC ALT, it takes 45 seconds to reach the clean speed with flaps up.

So 5'00''- 1' - 45" = 3'15" is the climb time in second segment you have.
Those 3'15" at groundspeed 140 kt with gradient 2,4% give you ascent to 1105 feet AFE, 5 mins TOGA limit observed.

Or a reversed calculation: To climb up to 800 ft with 140 g.s. on a 2,4% gradient, you only need 2'17". There are still remaining 2 mins and 33 seconds left for the ground roll and acceleration, before hitting the 5 mins limit!

2) Mach E Avelli's perspective.
Use the opinion of your TREs, if necessary TRE from CAA who flies with a more realistic operator, to explain that accel. at 400 feet is interfering with duties for engine malfunction handling. The way you have it now is completely upside down.

Force the FLT OPS ENG to give you room for working by the code of industry's best practice. Own solutions bring own problems. No need for that.
400 - EFATO drill actions
800 - accelerate if ready,
1100 - accelerate the latest to observe the 5 mins limit.

toung
10th Jun 2019, 10:56
@toung I suggest to use the following two step method to convince your flight ops engineers into a higher ACC ALT

1) safelife's calculation (put your own time values as appropriate)
- a: I assume it takes 1 minute from setting the TO POWER to the start of the first segment (V2 + positive climb);
- b: then you will climb at no less than 2,4%, which is the regulatory minimum;
- c: I assume after reaching the EO ACC ALT, it takes 45 seconds to reach the clean speed with flaps up.

So 5'00''- 1' - 45" = 3'15" is the climb time in second segment you have.
Those 3'15" at groundspeed 140 kt with gradient 2,4% give you ascent to 1105 feet AFE, 5 mins TOGA limit observed.

Or a reversed calculation: To climb up to 800 ft with 140 g.s. on a 2,4% gradient, you only need 2'17". There are still remaining 2 mins and 33 seconds left for the ground roll and acceleration, before hitting the 5 mins limit!

2) Mach E Avelli's perspective.
Use the opinion of your TREs, if necessary TRE from CAA who flies with a more realistic operator, to explain that accel. at 400 feet is interfering with duties for engine malfunction handling. The way you have it now is completely upside down.

Force the FLT OPS ENG to give you room for working by the code of industry's best practice. Own solutions bring own problems. No need for that.
400 - EFATO drill actions
800 - accelerate if ready,
1100 - accelerate the latest to observe the 5 mins limit.

Many thanks for very logical thinking and I absolutely agreed.
I will try my best to do that.
I will try to demonstrate them in simulator also.

FlightDetent
11th Jun 2019, 04:45
Just curious: When using the standard Boeing technique, does the 777 accelerate in level flight OEI or climbing slightly?

toung
11th Jun 2019, 15:16
Just curious: When using the standard Boeing technique, does the 777 accelerate in level flight OEI or climbing slightly?

Slightly climb rate about 50-100 ft/min in OEI like this.

SFI145
12th Jun 2019, 00:14
Something that has always puzzled me. Why is the takeoff minimum acceleration height 400 ft but the go-around is 800 feet? Also, an obstacle must be cleared by 35 feet on the net flight path. Surely if I were repairing the roof on my local church and a B777 with one engine on fire came over my head 35 feet above me this would be somewhat alarming?

FlightDetent
12th Jun 2019, 05:48
Per ICAO Pans-Ops Doc 8168 there is no such thing as acceleration during G/A, the gradient profile expects you to climb all the way to MisAp altitude.

Hopefully the aircraft will actually be climbing above the net profile, and there is a minimum gradient they need to achieve too. However in case where
- you are the critical limiting obstacle
​- or you live at the end of TODA

​​Expect a lot of rattle and shake. You will be quite used to it somehow, as the quad engine airplanes (soon to be extinct tho) will be buzzing by even with all operative.

N. B. Fire is not your greatest concern. That is something which happens outside the casing, inside the nacelle. The core would still be thrusting rather well.


​​​

john_tullamarine
12th Jun 2019, 09:36
Why is the takeoff minimum acceleration height 400 ft but the go-around is 800 feet?

400 ft third segment is historical and based on early ICAO documents. I am not aware of any standardised requirement for a miss at 800 ft, although that is quite common throughout the Industry. Generally, you will be initiating the miss at or above whatever the relevant height is for the particular approach. Main thing to keep in mind is that the required configurations are different for OEI/AEO.

Also, an obstacle must be cleared by 35 feet on the net flight path. Surely if I were repairing the roof on my local church and a B777 with one engine on fire came over my head 35 feet above me this would be somewhat alarming?

Alarming all around. Keeping in mind that the gross gradient will be somewhat better than the net, and the height delta increases the further downstream we go, you should expect an increasing clearance as the takeoff continues. If the failure is well after V1 (ie better than the AFM story) then you should be well and truly higher than necessary in most situations. The crew should see the gross gradient (or a little bit better) while we run the clearance sums based on a degraded net gradient presumption.