UAL and Flaps 40

[FLYLOW22]

FWIW, UA did not lock out the 737-300/500.

It was a hush kit to be used with JT-8D engines. 727/737-200/DC9.

 

[maru657]

United locked out the flap 40 position because some idiots racked all of the heat off on landing at about 50 feat and with flaps 40 the 727 will stop flying NOW! They actually bent some airplanes.

 

[b707guy]

Similar thing with Pratt-powered DC-8s, for stage 3 noise compliance. They are restricted to 35 degrees flaps for landing, except in an emergency. A small break-away tab blocks the flap handle from being moved beyond 35 to the original 50 degrees position. CFM-powered DC-8s are stage 3 without this restriction.

Our last stage 2 airplane (a -61) was restricted to 35 degrees max as well, but also had an alternate 'normal' landing flap setting of 25 degrees. Really funny that a 'normal' flap setting in that airplane is an 'emergency' flap setting in the rest. Especially in a plane that had non-modulated anti-skid and reverse thrust that produced more noise and forward thrust (or so it felt) than anything else... All for the sake of noise reduction.

 

[eaglesview]

United locked out the flap 40 position because some idiots racked all of the heat off on landing at about 50 feat and with flaps 40 the 727 will stop flying NOW! They actually bent some airplanes.

Where do you get this nonsense?? As for the 737's only the 200's where locked out of flaps 40. This was for noise certification.

 

[75 Driver]

The 727 lockout was definately done at UAL because of several aircraft damage incidents. Boeing and SAM along with FAA input took flight standards down this path a long time ago, if I remember correctly it was about 1986 this went down in the 72 fleet.

 

[tomgoodman]

Dropping like a brick

We could use 40 Flaps at DAL, but were told in 727 school that some carriers had prohibited that setting due to "sink rate" accidents in the early days of the airplane, when pilots were transitioning from straight-wing props. One example was a UAL crash at SLC in 1965. According to reports, the approach in that case was extremely unsafe: (over 2000 ft. high at the OM, sink rate 2300 FPM, hit short with 14.7 vertical Gs).

 

[SpauldingSmails]

Multiple answers: Flaps 40 definately locked out on some noise kits,

However long before that some airlines locked out flaps 40 due to some awfull landings and damage from said landings.

Remember some airlines really do not hire aviators, they hire people that will do what they are told and get along with others.

Perhaps it was both. Maybe flaps 40 was blocked to abate the noise of a B727 making a 14G impact. I'm sure that can't be very quiet.

 

[luckytohaveajob]

Flaps 40 keep the nose down. On low visibility approaches and with airplanes prone to tail striking flaps 40 shows good judgement.

 

[aa73]

IIRC, AA blocked out flaps 30 (safety wired) on the Raisbeck kit 727s. Flaps 25 was standard and we could only use 30 in an emergency. It's been too long so I may be wrong.