B738 Pilots, especially GOL Airlines. Little help.

[BOAC]

For misd-agin's benefit, here is the relevant page from Boeing, 2009. Of course they could be wrong.................

19
Factors Effecting Stopping Distance
• Speed
– Higher approach speed more distance
– Example 737-800 has increased flaps 30 and
40 approach speed for tail clearance.
• Wind - headwind good, tailwind bad
• Slope - uphill good, downhill bad
• Temperature, Altitude
• Inoperative equipment

I expect the 900 too.

[Denti]

Additionally, the SFP does use slower approach speeds, higher pitch attitudes as stated in the FCTM as well

That might depend if you have the two position tailskid which is not necessarily part of the SFP package (it is an customer option).

[Johnny Tightlips]

I was given a great piece of advice by a captain about landing the -800. Runways between 2200 and 2400 meters are the most dangerous for landing. In your mind and on paper the runway sounds long enough but when you add a wet runway, a tailwind and some floating it starts to run out very quick! If the runway is less than 2200 you are prepared and try your best to get it on the markers.

A quote from another captain while landing on a short wet runway one day: I don't care how hard you hit the runway as long as it's on the 1000 foot markers

[BOAC]

I don't care how hard you hit the runway

- has he/she looked at the oleo compression graphs?

[sudden Winds]

Quote: I don't care how hard you hit the runway

It might have been a she then.... just kidding!!!!

[Denti]

I don't care how hard you hit the runway as long as it's on the 1000 foot markers

And then he bounces happily along the runway until the midway marker?

A good positive touchdown is something thats good, a crash or bounce is not really good.

[Johnny Tightlips]

People get a grip it was only a figure of speech

[sudden Winds]

Folks what app category does the B738 fall under?
Thanks...

[misd-agin]

lbs Vso F15 F30 F40

120,000 108 104 102
130,000 112 108 106
140,000 117 112 110


lbs Vref F15 F30 F40

120,000 142 135 128
130,000 148 141 133
140,000 154 146 139


Vso x 1.3 F15 F30 F40

120,000 140 135 133
130,000 146 140 139
140,000 152 146 143

Vso x 1.25 F40

120,000 128
130,000 133
140,000 138


Vref Flaps 15 is 2 kts 'faster' than 1.3 Vso. So far Flaps 15 Vref has been adjusted by 2 kts.

Vref Flaps 30 is Vso x 1.3. No adjustment.

Vref Flaps 40 (Vso x 1.25) is 4-6 kts SLOWER than Vso x 1.3. The exact opposite of INCREASING the approach speed due to fuselage length.

Vref Flaps 40 uses Vso x 1.25 which is the same as Vso x 1.3 minus 4-6 kts, which would result in a slightly higher pitch attitude.

[JPJP]

We've been operating 737-700's into KEYW (Key West) for some time now; 1463m

[Denti]

Yep, the 700 is a real nice plane for short runway, and i absolutely love the climb performance (we use full climb thrust even if derating to 2).

[bubbers44]

Our airline was based at SNA in southern California and we had 737 100's and 200 and 300's flying out of there for over a decade with usually every seat full with no problem with 5700 ft of runway. With the higher powered Boeing 737's now Key West is easy. I am glad they are getting good service in there now. It is a fun place to visit but a bit of a drive from MIA. About 3 and a half hours with no traffic.

[exeng]

What has this reply got to do with the OP's original query/

The 700 is a great performer in LDA - the 800 is not. Much like the 200 was a great performer but the 400 was not.


Regards
Exeng

[sudden Winds]

math...

misd agin,

737-700 at 55 tons Vref 30=129 kts
737-800 at 55 tons Vref 30=136 kts
Both have the same wing...

737-700 at 65 tons V1 Vr V2= 136 137 144 kts
737-800 at 65 tons V1 Vr V2= 141 143 153 kts
Again, same wing.

Out of B737Ng FCTM updated July 29, 2011 Page 3.7

Takeoff speeds are established based on minimum control speed, stall speed, and tail clearance margins. Shorter-bodied airplanes are normally governed by stall speed margin while longer-bodied airplanes are normally limited by tail clearance margin. When a smooth continuous rotation is initiated at VR, tail clearance margin is assured because computed takeoff speeds depicted in the PI chapter of the FCOM, airport analysis, or FMC, are developed to provide adequate tail clearance.

I will be taking a look at those numbers you posted.

Thank you for contributing!

Regards,
sw.

[misd-agin]

Sudden Winds - it's tough to be wrong, and it appears that I could be depending upon how you want to frame the arguement.

S80 uses Vso x 1.25 (approx)
757 uses 1.3
763 uses 1.25
772 uses 1.25
738 uses 1.30 for F30 and 1.25 for F40
737-700 appears to be using 1.25 for F30


763 has a tail strike at a lower pitch attitude than the 738 and 757 but uses 1.25.

Maybe there's more to chosing 1.25 or 1.3 Vso to determine Vref than I(we?) know?

[porch monkey]

Is it possible that it is fiddling the figures to fit with the philosophy that Boeing use regarding flap manouver speeds? On the 737 it goes basically vref 40 + 70 to vref 40 + 50 for flap 1, + 30 for flap 5 etc? In order to keep the manouver margin, might some need to be increased? Hence the differing speeds for what one would otherwise think? Is the same philosophy used on the larger boeings? I only have experience with the 737.....

[BOAC]

Is it possible that

- see Post #21?
"– Example 737-800 has increased flaps 30 and
40 approach speed for tail clearance."

There was me thinking the manufacturer would know, too

[misd-agin]

BOAC - if Flaps 40 is an increased Vref for tail clearence what speed was it increased from? It's already at 1.25 Vso, which is basically the lowest multiplier used(either 1.25 or 1.3 x Vso).

And the 767-300 has the lowest pitch attitude for a tail strike but it uses 1.25 Vso also. But the 757, which has a higher pitch attitude for a tail strike, uses 1.3 Vso.

It might be to you but perhaps you can clarify the 767-300 vs. the 757 as well as the 737-800 F30 vs. F40 "increased speed" issue?

[BOAC]

Originally Posted by misd

It might be to you but perhaps you can clarify the 767-300 vs. the 757 as well as the 737-800 F30 vs. F40 "increased speed" issue?

- in a word, no, and I have no wish to. I take the simple 'approach' here and if that is the speed the manufacturer dictates that will be the speed I try to fly. I prefer to leave working out those speeds to those who understand them.