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andreadebiase

landing with flaps 30 or 40?

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My SOPs that i follow require a f30 approach unless performance reasons dictate otherwise or if its specified in the Airfield brief.

 

For all LVP ie Cat II III landing f40 is mandatory.

 

But of course both flap settings are a certified landing flap!


Vernon Howells

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On the 737-800, GOL uses flap 40 because of the higher risk of a tail strike with flaps 30...

That seems a bit dubious. Any reference?


Matt Cee

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GOL do occasionally land 737-800's on a 1300m long runway though. That'd be a flap 40 job.

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Flaps are for the birds.....it's all about that no flap landing!


FAA: ATP-ME

Matt kubanda

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That seems a bit dubious. Any reference?

Yes, in this video, at 3:15, the captain explains (in portuguese), that Gol adopts flap 40 because of the lower risk of a tail strike... In all 737-800 of Gol fleet there is a placard on the panel saying flaps 40 is standard for landing...

 

 

http://www.airliners.net/photo/Gol-Linhas-Aereas-Inteligentes/Boeing-737-8EH/2223813

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Fiu ! to each their own I guess. Flaps 40 waaay out there, almost 8,000 foot runway. I guess the airline doesnt mind the extra fuel.

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Fiu ! to each their own I guess. Flaps 40 waaay out there, almost 8,000 foot runway. I guess the airline doesnt mind the extra fuel.

Your final flap setting isn't going down until close to the runway, how much fuel do you think is really being burned? - David Lee

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Enough that the majority of operators dont use the setting needlessly. Besides, I am not buying this tail strike business.

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I just tried a comparison in the 737-800 on a three degree slope at Flap 30 and 40, with the speed set at Vref + 5.

 

Flap 30 (Vref 148):

Pitch: +2 deg

N1: 59.1%

FF 1200 kg/hr

 

Flap 40 (Vref 141):

Pitch: +0.5 deg

N1: 65.6%

FF 1780 kg/hr

 

In this case pitch angle will be approximately 1.5 degree more during flare at flap 30 than at flap 40. That brings you closer to the tailstrike limit.

 

Assuming about 2 minutes stabilised at Vref the extra fuel burn is 38 kg. Not a lot but if you scale it up by the number of landings each day and it starts to become significant. The higher N1 means more noise of course.

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ki9cAAb.jpg

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There is a nice chart in the FCTM pg 6.18 for the 738 illustrating flare pitch and tail strike angles and various speeds.  VREF30-5 (recommended touch down) requires less pitch than VREF30-10, which at about 8 deg is close to the 10 deg tail strike region.

 

Charts are not provided for Flap40 unfortunately.  However, a touchdown at VREF30-5 assures at least 4 deg of separation from the tail strike zone.  Perhaps that operator has had a bad experience and they issue a procedure rule to try to prevent recurrence when all that is required is a little training on approach and landing speed management.


Dan Downs KCRP

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I found this Boeing SOP. Low fuel burn is in line but they seem more concern about safety in the approach and a missed approach possibility more than anything else including a tail strike. I would imagine there is a greater threat in the -900.

Maybe they operate in enough short runways like Congonas that the use Flaps 40 standard.

 

http://www.boeing.com/commercial/aeromagazine/articles/qtr_02_10/5/

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I just landed at KSAN runway 27 and doing it at flaps 40 was much better than my last landing in the same airport and same runway 

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Enough that the majority of operators dont use the setting needlessly. Besides, I am not buying this tail strike business.

Flaps 30 requires higher speeds, so I don't know how much fuel you are really saving. Your full flaps are down for maybe 3-5 miles max. There are many reasons for using flaps 30 instead of 40 so unless you can show me the airlines that choose 30 are doing it for fuel, I will not believe it. I have heard that some airlines use flaps 30 for higher speeds not any cost savings and others have said for tailstrike reasons. - David Lee

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I am nor a pilot in type nor an operator. In the table I posted fuel savings is in the spotlight--did you see it ? And with so much flap 30 landing ops have you heard of one tail striking lately ?

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I am nor a pilot in type nor an operator. In the table I posted fuel savings is in the spotlight--did you see it ? And with so much flap 30 landing ops have you heard of one tail striking lately ?

 

I have no idea what you're talking about, you made a claim on why operators use a certain flap setting. Now you admit you have no idea. - David Lee

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