Does anyone like the 737NG wing?

[slip and turn]

I was chatting to a 737NG driver the other day and was very surprised when he appeared to come out with the phrase "Boeing say that the NG wing is the worst they have ever designed". I didn't have time to explore that very far with him, but I was taken aback.

I should say that I had provoked the statement by commenting that I thought I'd read that the NG wing was designed to be less problematic with regard to icing i.e. less of a need for de-icing / anti-icing on turnaround. He did back up his statement by mentioning the tendency for the fuel to become severely cold soaked on two hour hauls at altitude which then caused problems later.

I came away a bit perplexed by what I had heard.

Is there a clear consensus one way or the other about this wing?

Obviously the slats problem is one bad thing, but is icing an issue too?

[Colonel Klink]

In part, I would disagree with that. The Ng wing weighs 5 tons more, but the aircraft cruises 20-30 knots faster, flies considerably higher, lifts more weight and uses less fuel. As far as the icing issue, yes, that should have been rectified at testing and is a pain for all operators particularly at this time of year. Also, the NG is slightly less speed stable on approach-the speed fluctuates whereas the Classic tends to hold it's trimmed speed better. A minor complaint but in gales or strong, gusty wind a Wind shear GA will be required more often.

[A and C]

It is probably not the best pilots aircraft that Boeing have built (most say the B727 was) but it will do the job safely and a lot faster than the classic.

It has got icing issues but nothing that can't be delt with using the proper drills.

I like flying the aircraft and have no issues with it at all but it is not the best aircraft to hand fly but is far from being the worst. I have landed the aircraft in a quartering 28G48KT cross wind the speed acording to the PFD speed tape was all over the place but it is over sensitive, in gusty conditions it is best to use the standby ASI as this is better damped and avoids you chasing the speed.

As for hand flying airliners the Lockheed L188 Electra is the best I have flown by far.

[bodarovitch]

737NG

It is true that the 737NG is certainly not the best Boeing and regarding the wing,there is this NEI problem but one point really strange are the landing speeds(VREF) much too high for a short/medium haul a/c.
For the 737-800 at 65T(MLW) FL40: 141Kts
FL30: 148Kts
And the wing is much bigger(span& chord) than the previous models!
Compare to the 757 I flew before it is higher and also the 757 brakes are much more efficient.
Boeing should have built a small 757 or a small 777.
It is nice to have same rating as the old series I flew also in the past but there is a moment when we have to stop doing"new" model with "old" one.


Happy landings!

[5150]

As the Colonel mentions, it is a very efficient wing, so it can only be good news for the beancounters.

From a pilot's perspective, I'd say it is quite hard to slow down, so requires a bit more planning ahead as the speedbrake is only really useful at higher speeds.

I've flown with guys on the 700, who have come from types such as the 777, 744 and A340 and they all say the 700 is the trickiest to fly.

Apparently the speedbrake on the 777 will double your descent rate. . .

That said, I enjoy flying the 700 as no approaches are rarely the same in it.

[Fredairstair]

Am surprised no-one has mentioned the comedy approach speed. Is it 1.4 x Vs rather than the more usual 1.3?

[ScottyDawg]

According to the Boeing Flight Training Manual Vref 30(or 40)+5 (or relevant applied wind factor), is the recommended approach speed - for full manoeuvre capability at Flap 15 (Go Around) configuration. - I'm not sure what the relevant Vs factor above stall speed for either configuration is - perhaps someone has the figure to hand..!

One thing that is quite concerning to view is the high/low speed buffet margins on the -800 in ISA+ conditions. This has led to a few instances of high altitude stalling which have resulted in quite a few operators developing SOP's limiting flight crews to stay within the FMC calculated optimum Flight Level(s)

Cheers

ScottyD

[mrjet]

The -800 and -900 is not limited by Vmcl or Vs, the approach speeds are limited by aft body clearence. A -700 and an -800 at the same weight would have different Vrefs in order to provide more body clearence for the longer -800.

The NEI problem can be avoided/reduced by landing with less fuel. This time a year I aim to land with less than 4 tons and usually the frost comes right off after uplifting warmer fuel. A big "gotcha" is when landing in rain with cold soaked wings and low temperatures since the hold over time after de-icing is very short.

In the summer it's rarely a problem, but i've seen frost on the wings in temperatures above 20 C after landing.

[BOAC]

Originally Posted by mrjet

This time a year I aim to land with less than 4 tons

The technique of 'running down' wing tanks by retaining centre tank fuel is an effective solution to that, as long as CofG and ZFM issues are addressed and there is enough in the wings to cope with that 10,000,000 to 1 double ctre tank pump failure. The 'cold soak' lines are good, but don't help much in winter at 'cold' airfields.

[Bumpfoh]

The technique of 'running down' wing tanks by retaining centre tank fuel is an effective solution to that, as long as CofG and ZFM issues are addressed and there is enough in the wings to cope with that 10,000,000 to 1 double ctre tank pump failure

The NG has a tendancy to loose CWT pump prime if they aren't used regularly (i.e no fuel in CWT for multiple sectors) and then a relatively small CWT uplift will not self prime the pumps.

If this occurs it can take up to 6K in the CWT to successflly prime the pumps, as such the above is done with an element of risk depending on the initial CWT load. You would need to establish positive CWT pump pressure prior to enacting the above.

BTW is this an apporved procedure??

[worrab]

Would this be related to a recent 737-800 turnaround I saw? The air temp was about +7. The pilot borrowed some steps and poured a large coffee jug (1-2 litres?) of steaming water liberally onto the inboard section of the right-hand wing. Apparently satisfied, the flight took off with no further incident. Can't believe this would be a SOP.

[Dogma]

As my father would say, he may as well be pissing on it. Pouring Hot Water, spirits (yes its been done) on the wing is a bad idea.

The 737-800's biggest problem is stopping, look at the tankering/weight restrictions into any field less than 2500m.

[Dogma]

Sorry in the WET WET WET I mean!

[enicalyth]

Oh Dear!

No the 737NG is not Boeing's best effort. Given the strictures and constraints over what had to be done to which and in what constraints with how much cash when you look at its jiggles, coggles and kinks (as opposed to cranks) the wing tells its story loud and clear. Voltaire's Dr Pangloss argued that everything is for the best in this best of all possible worlds. He never went so far as to suggest that if anything exists then because it exists it must be perfect. Or are we losing critical faculty? The 737NG is more Bogan than Boeing, but "She'll too, she'll too, she might have been a poy". Nothing wrong with her that a healthy discount and ready delivery date can't cure. Now which company do I work for again?

[cjam]

couldn't have said it better myself.Van and Wolf have got nothing on the NG, and they can critically facultise with the best of them.

[Old Fella]

Retaining CWT fuel

I find the idea of maintaining CWT fuel any longer than is necessary to be less than ideal fuel management practice. Apart from wishing to use fuel, which for any number of reasons may be unable to be transfered at a later stage of the flight, it would seem to me that it would be desireable to maintain fuel in the wing tanks for as long as possible, not least to maintain wing strength and reduce wing loading.

In the unlikely event that CWT pumps are unuseable at a later stage of a flight the fuel in the CWT is about as useful as fuel in the underground storage tanks, a situation which could prove embarassing if both destination and a suitable alternate cannot be reached with the remaining wing tank fuel.

[underread east]

Does the 737 not have a max allowable fuel limit in centre tanks with less than full wings? 757 limit is 2300kg for the SF I fly, above that I MUST burn centre tank fuel first.... I would have imagined that the 737 would be designed with a similar philosophy - in which case burning wing fuel down to avoid post landing icing and retaining the centre tank fuel would be contrary to the Boeing Operating Manual...?

[captjns]

To maximize uplift of warm fuel in the wing tanks while landing without concern of landing with sufficient fuel, burn the CWT down to about 500 to 540 kgs. After the CWT pumps are turned off the CWT will scavenge down to about 450 kgs. I heard that Boeing picks up the expense of de-icing costs due to NEI. Anyone else hear that?

[Go Smoke]

What's NEI?

Thanks,

GS

[Funnel Cloud]

NEI = Non Environmental Icing

This means, after a longer flight (let's say 2 hours or more) at altitute, the fuel in the wing tanks becomes very cold. After landing, this cold soaked wing could cause ice build up on the wings.

This way deicing is often required, even though the outside air temperature may be +10 degrees