Originally Posted by
safelife
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.
Originally Posted by
toung
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.
Originally Posted by
tomuchwork
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.