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787 encounters more problems

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787 encounters more problems

Old 23rd Oct 2010, 06:13
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787 encounters more problems

The first Boeing 787 delivery is still months away, but the new plane is already threatening to cause flight delays.

The FAA has been thinking about the new jet, and they’re a little concerned that it might just be too fast and powerful. They’ve put out new guidelines regarding how closely other aircraft can follow the new plane, as they’re concerned that the big wings and big engines of the 787 will shake up the air in front of the planes waiting on the runway.

Right now planes like the 747-400 have a four-mile separation requirement, but the new 787 is getting a ten-mile rule. It’s not just one plane either, as Boeing’s latest version of the 747 — the 747-8 — is also subject to the new rules.

The FAA just wants to ensure that the new airplanes aren’t bullying smaller jets and older aircraft on the runway. Right now it’s just an interim thing while the planes go through testing, but if the restriction sticks it could be an issue as planes are forced to lineup on the runway.

The FAA might just be taking a conservative approach at this point, as even the Airbus A380 doesn’t require a ten-mile spacing. Boeing is already chatting with the FAA about this new guideline, as they realize this spacing could cause some of their customers to be not so happy. Just imagine a runway full of 787s on a busy summer day at JFK

Last edited by jackx123; 23rd Oct 2010 at 06:34.
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Old 23rd Oct 2010, 06:16
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FYI the A380 is causing a fair amount of havoc with its wake turbulence , especially in RVSM airspace , vertically as well as longitudinally.
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Old 23rd Oct 2010, 06:44
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Just imagine a runway full of 787s...

If the runway were really full of 787s they'd have more to worry about than wake separation.
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Old 23rd Oct 2010, 07:47
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The article where this thread is drawn from also goes on to state that the A380 was also given the same 10 nm requirement.... The FAA openly admits for the 787 it is an initial very conservative approach until all testing has been completed, including operation use at busy airports (as it was for the A380).

Too powerful? Only if the pilots don't know what they're doing with that power. Some carriers operate the 777-200LR with the GE90-115(B1L1) engines. Same fuselage as -200 models but with -300 wings. With a OEI situation, especially at T/O or G/A circumstances throwing the good engine to max thrust will throw that aircraft on its back, especially if at a light weight. Hence Boeing have a V2 floor for the -200LR (protected by a min Vref of 137 kts in the QRH) as well as a min take off weight to provide protection also.

(Hitting the TOGA switches once provides 2000 fpm performance. I can't think of too many scenarios where hitting the TOGA switches twice, or fire-walling the thrust levers to give MCT is needed).

See "The Migration to Higher Thrust Engines and the Effect on Control Speeds" by Steve Nelson from Boeing.
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Old 23rd Oct 2010, 17:01
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@TopTup...slight thread deviation. Since u mentioned use of TOGA power on the good ol 115k GE's I was wondering if u could possibly comment on this....
http://www.pprune.org/tech-log/43136...ml#post6009380

Take your time...but read all posts. Makes for very interesting reading...
Looking forward to your post
Cheers ..
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Old 23rd Oct 2010, 21:44
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Thankfully on the Boeing jets, MCT is readily available, no pleading your case thru software algorithms.
Funny, I know a few 777 pilots who would be inclined to disagree.
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Old 23rd Oct 2010, 22:10
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Sensationalist, incomplete and... incorrect

Here is a link to a Seattle Times report on the original FAA order "debacle"...

Business & Technology | FAA rescinds precautionary order about Boeing's new jets | Seattle Times Newspaper

And a few excerpts by way of summary:

The order applied to the 787 Dreamliner and the new version of the jumbo jet, the 747-8. Brown said the two aircraft should not have been included in a single order.
A new order giving the necessary separation distances for the 747-8 will be issued in the next few days, she said. A new order for the 787 Dreamliner will not be ready for more than a week.
Brown said the order was intended to apply only to Boeing's flight-test airplanes, although that qualification was omitted from the order. Boeing has six Dreamliners and four 747-8s in flight tests.
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Old 24th Oct 2010, 05:52
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AK, I'll have a bash at it....

First and foremost, [crudely] TO/GA is a pitch mode whereby attitude and thrust are used to achieve what you have asked from the aircraft. Appreciate that and half your battle is won.

At >50 if TO/GA is not already active A/T is inhibited until reaching 400 ft altitude (you have manual thrust control). At 80 kts pushing TO/GA disarms LNAV and VNAV, nothing more, nothing less. At 100 kts a barometric snapshot of the ambient conditions is taken and applied (to assist in engine parameters DESPITE what you have entered into the FMC). So, for the competent 777 pilot you should be also checking the top left hand side of your MFD at 100 kts to confirm TAS appears to verify all is working well, just as you do engine parameters and a "80 knots" call. The 777 FMC is smart. Too smart for some who do not understand what it is telling you or what it is doing, hence overuse of FLCH or the complete inability to use V/S or "understand" VNAV.......VNAV activates the inputs the "pilot" selected to the FMC but corrects for pressure alt, etc as well as both real and predicted winds. For assumed T/O conditions control speeds are determined at the actual temperature, not what you/we the pilots want to tell the aircraft it is.

For whatever reason you want MCT on your 777:
Firewall the thrust levers, but be prepared for what you have just asked the aircraft to do for you. The EEC monitors thrust settings but DOES NOT relieve the pilot from monitoring engine parameters him/herself. If conditions are encountered during the takeoff where additional thrust is required [windshear] the crew should not hesitate to manually advance thrust levers to maximum takeoff thrust. Thrust levers should not be advanced beyond the fixed derate limit unless conditions are encountered during a takeoff where additional thrust is needed on both engines [again, windshear]. A thrust increase during an engine failure could lead toward loss of direction control. (All paraphrased from the FCOM/FCTM).

Advancing the thrust levers removes all derates and assumed temp factors.

So, I read all this to say that Boeing tell us to use the automation, know, understand and comprehend what the automation is doing and when you want to be a pilot again, know, understand and comprehend what you are doing. (A fast becoming rare attribute). Taking manual control will remove derates and the assumed temp considerations and the engines will give all they can with respect to ambient conditions, ie without cooking themselves.

Hey, where and if I'm wrong then tell me! The day we stop (wanting) to learn is the day we should put the wings away. I can just as easily misinterpret things but this is how I appreciate thrust management on the 777.

Last edited by TopTup; 24th Oct 2010 at 06:12.
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Old 28th Oct 2010, 03:08
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You can see at least 21 in store in Everett ! Most with the windows taped up with black tape.

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