400 versus 8: Pilot's perspective

[Will]

Does anyone have any perspective on the differences between the -400 and the -8i from the pilot's perspective? Do they handle differently? Do they land differently?


(Maybe this should be in the Pit?)

[emerydc8]

From what I hear, a lot of the guys who have been on the -400 a long time don't like the -8. The brakes are similar to the -400, but the landing weights are much higher, so there are a lot of brake overheats and you have to treat it more like a classic and use the whole runway. When it's light it will throw you back in your seat on takeoff. But when it's heavy, it's a real dog. Plus, you have the issue of engine icing around CBs. It takes a lot longer to start the engines. There are a lot of FMC "anomalies" that have not been resolved. A friend who is an NCA captain said that Boeing pulled their best engineers from the project when the 787 got into trouble and they never really came back to fix the problems they left.

Jon

[Will]

Thanks for the input, Jon. I see the -8i overhead here in Chicago, and of course in several cities in China when I'm traveling there. I've always wondered how it was as a plane. I've heard rumors that it was never really meant to be a commercial product and the assembly line was going to be shut down after the requisite number of VC-25's were produced. But that's just rumors.


FWIW to my eye, it seems a little too stretched. I know it's only ~20 feet longer, but it takes the 747 from looking strong, to looking overextended on its frame. Others will obviously disagree, since that's an aesthetic opinion, and that's fine.

[emerydc8]

FWIW to my eye, it seems a little too stretched.

That's the other bad thing. Aside from the increased chance of a tail strike, there seems to be all kinds of features not seen on the 744. Reminds me of the L1011.

 Landing; pitch augmentation.
 Spoilers 4, 5, 8, and 9 will automatically move during landings to increase the pitch attitude.
 When the flaps transition to 30`, the aforementioned spoilers will extend slightly increasing drag.
 Below 260' RA, the aforementioned spoilers will extend and retract predicated on control column inputs. Control column aft retracts the spoilers and control column forward extends the spoilers.
 Pitch augmentation is removed if approaching a stall.

Horizontal stabilizer
 Tail Strike Protection
 During takeoff or landing, the stabilizer trim system calculates if a tail strike is imminent
 Activation of tail strike protection does not provide feedback to the control column.

[United744]

Why are the engines more prone to icing? Is it materials, or blade design?

[emerydc8]

I'm not sure why, but the procedure is different for the -400 and not nearly as critical.

[United744]

WOW. I knew it was bad, but "if can't clear by at least 50 NM, turn around" is surely a broken design?!

Doesn't the 787 have this same problem?

[Will]

Wow, agreed. "Turn around" is a sign of a pretty serious design flaw. Wikipedia tells me they're working on the issue.

[stekeller]

It looks like this engine icing issue has been resolved, but may take a while to be incorporated into the fleet.

http://aviationweek.com/technology/higher-altitudes-cleared-ge-powered-787-747-8-icing

- Stekeller
KGED

[Magoo]

Woah, where do I start,

The -8 is an absolute pleasure to fly, it responds nicely to control inputs and is very easy to land, especially at high weight, 340 Tons +.
The Vnav does have a few brain farts once in a while but not that bad.
The engines Ice crystal Icing issues are being fixed with a modification of the inlet guide vanes on the compressor.
The extra length doesn't affect its landing characteristics, the only difference is the way it handles turbulence in flight, kinda wiggling like a fish, only slightly as opposed to the vertical oscillation on the 400.
The Autothrottle works well and can be kept engaged during manual landing like a 777.
The brakes are extremely powerful and don't overheat any more than the 400, above 300 Ton landing we'll use full reverse to keep the temperatures low.
And last but not least, the power this airplane has... and quiet too!

[emerydc8]

Thanks for the input.

The brakes are extremely powerful and don't overheat any more than the 400

 466 hot brake events in 2014 for the 8F. Consider using the lowest Autobrake selection (dry runway 2 or more and wet runway 3 or more) that will stop the aircraft within the confines of the runway length. Do not plan Autobrake selection in reference to stopping for a particular taxiway. Rather than using heavy braking to make a runway exit, it is better to leave the autobrakes on and continue to the next exit.

I'll presume you don't work for a major ACMI operator based in Purchase, New York.

[Magoo]

Nope, not Atlas, I've never seen more than about 400 deg after landing, and even at max landing weight and we do choose the runway exit, with max reverse, also finding we are better off leaving the auto brakes till about below 60 kts, carbon brakes apparently love the on pressure application only.

[stekeller]

Fascinating comments on the -8!

I do have a vested interested in them but I will leave it there out of respect for HH and this forum ;-)

But as a side note, I am very relieved at the recent UPS order for the 747-8F. It was looking like the 747 production line was going to be shut down soon, and may now be kept going long enough for the expected replacement time for older 747s (mostly freighters) to arrive.

That and Boeing has talked at various times about further improvements/refinements to the 747-8 (look up "Project Ozark") to reduce weight, improve aerodynamics and alter flight control software to improve efficiency and range. GE is also implementing PIPs (Performance Improvement Package) for the GEnx engines. So I am hopeful that this will keep the 747 competitive in spite of being a "quad" and the amazing things that "twins" can do now with their amazing power and efficiency.

This will also be good for PSX mind you. The pilot type rating on the -400 and -8 is the same (with a small differences course required - sometimes only in the full-flight simulator with no flight in the actual airplane required depending on the airline) and 747-8 pilots can use PSX to learn the airplane and stay current.

- Stekeller
KGED