727 Landing Question...

[mtsu_av8er]

Doug (and anyone else that has flown or does fly the 727):

I know that in all of my dispatcher training, we always plan for a landing with 30 degrees of flaps in the 727, and from what I've been told, there isn't much of a hit should the crew decide to use 40 degree. With regards to performance, how much of a difference will that extra 10 degrees make? How often is it used? I've heard that some operators actually lockwire the lever so that 40 degrees can not be used.

What's the deal with that??

How about on the 737?

 

[MDPilot]

Forty degree flaps were locked out as part of the noise reduction modfications. Theory is that a lower power setting on final is needed if 30 is the max flaps used. As far as a performance degradation, remember that the 727 was originally designed to operate in and out of 5000 ft fields. As most of the fields used by 727s today are probably longer than that, the lower flap setting for landing is not quite as critical, and the perf data is calculated on the 30 flap setting.

 

[flyover]

Eliminating 40 flaps was primarily to meet noise reduction standards in 727.

As for the 737: On the ones with the original wing, 40 flaps is rarely necessary. Might use it going into MDW or DCA. It will reduce approach speed about 5-6 knots.

On the newer ones, like the 800, it is used more often because approach speeds are typically about 7 or 8 kias higher on these airplanes, so you take what you can get as far as helping you slow down.

I was told by a Alaska captain that they only do 40 flaps/ power on landings in the -900s to avoid tail strikes.

The less flaps you use the better the airplane handles in a crosswind, especially a gusty one.

More flaps are recommended in low-vis approaches as this gets the nose down and helps in visually acquiring the runway.

Flaps 15 is also a normal landing flap setting. If the landing weight is low it is a good option. Very easy to make good landings. Also this is the flap setting for engine out and some other abnormals.

At some high altitude airports, in the 800, we have to use flaps 15 landings to give legal performance for go-arounds. This can result in very high touchdown speeds, bugging around 160 and flying 180 kts or more true. Very racy.