Why do Heavies ask for wind checks?

[FatesPilot]

Flying out of SFO, I constantly hear the majors asking for wind checks on final. This seems to annoy the tower at times.

I'm curious as to why they ask for the specific wind?

 

[banned username 2]

Not to be a smart a$$, but wind affects all planes.. not just the light ones....

 

[tdvalve]

Some of the SFO controllers are easily annoyed.

 

[MetroSheriff]

3 most often heard phrases in the ATL atc environment...


How longs the final today???

Can I get a sequence?

Wind check???

 

[VFR on Top]

'Cuz there's no windsock.

 

[BigFlyr]

Dumb question? Not really. While larger airplanes are less affected by wind than smaller airplanes they are also less manueverable so you have to anticipate your corrections for wind as soon as possible. Take in consideration higher approach speeds for larger aircraft that are near their max langing weights and it can get pretty exciting if the wind is doing something that wasn't expected.

 

[SDdriver]

You should try flying a BOX with a 15 or 20 kt direct crosswind. Talk about a challenge..Anyone who has flown the SD3 can second that. It's like having a barn door strapped to the side of your plane.

SD

 

[empenage]

When your rudder is as tall as a five story building youll ask for one too.

 

[profile]

Because we have a direct wind direction/speed readout in the cockpit, we know what the winds are for where we are. What we want to know is how much it might change between that point and the ground. Provides early heads up for windshear, etc. Remember, that much mass doesn't change direction in an instant, so we can't recover from wind changes like a light airplane can.

 

[wingnutt]

id like to run a follow-up question in that same vein. what speed does a typical heavy rotate/touchdown at? assuming normal conditions and weight...just curious

 

[TDTURBO]

100kts

 

[jetexas]

100 knots? Ouch, better have a good chiropractor! They touch down more like 130 and on up. Even in the jungle jet, we touch down from 115 or so and on up, depending on winds and weight.

 

[profile]

Varies, depending on aircraft and weight. On the MD-11 at max weight we rotate around 185kts and can approach over 170 kts with wind additives.

 

[flydog]

Actually touchdown should be slower than Vref. In the Westwind with a Vref of 131 knots the touchdown will come with about 90 knots on the ASI which is about 5 kts below Vso. Once you start the flare and chop the power these lead sleads run out steam real quick.

I flew with a NASA test pilot once that flew lifting bodies. The ref speed was somewhere around 300 knots. At 1500' AGL the flare started and touchdown occured at 150 knots.

Although I dont have much experience with swept wing jets I would venture a guess and say touchdown speed is somewhere closer to Vso than Vref

For some real fun check your ASI next time you are doing power on stalls in your favorite jet. I have seen it as low as 60 kts in the Westwind at the stall break

 

[80drvr]

Actually touchdown should be slower than Vref. In the Westwind with a Vref of 131 knots the touchdown will come with about 90 knots on the ASI which is about 5 kts below Vso. Once you start the flare and chop the power these lead sleads run out steam real quick.

Most large transport jets would get a tail strike if you decelerated that much below ref speed. Vref minus 5 is a typical touchdown target.