Jet Crew: Reverse Thrusters Failed in Chicago - Washington Post

Do a Google for "Boeing 727 landing flaps" and you will find
several NTSB reports about flap settings and crashes do to
autopilot problems. I do remember there was an article
about the FAA/Boeing restricting flap extension after a
series of landing accidents. Maybe some one remembers, I
think 40 was the reduced setting.

I just have a clear memory of the article in FLYING or Air
Progress.


--
James H. Macklin
ATP,CFI,A&P

"Bob Moore" wrote in message
. 122...
| "Jim Macklin" wrote
|
| If I remember correctly, the 727 had a series of landing
| accidents because the full flap setting was about 50-60
| degrees and if the pilot got too slow, they could not
| recover. Maximum extension was reduced.
| Looking on the Internet, I found a further limitation
for
| couple approaches with certain autopilots. Is there any
| early 727 pilot out there with the facts on the first
727
| and any changes in certification re flaps?
|
| Go back to your little airplanes Jim. The following
article is
| from the May-June 1965 issue of the Boeing Airliner. Is
that
| far enough back for you?
|
| "Flap Angle
| One of the factors having the greatest effects
| on stall and initial buffet speeds is the angle the
| flaps are set at during flight. The 727 flap angles
| are given in trailing edge deflections of 0, 2, 5,
| 15, 25, 30 and 40 degrees. An increase in flap
| angle increases the camber of the wing so that
| it will produce the same lift at a lower speed than
| a smaller flap angle setting would produce. The
| effect of flap angle on initial buffet and stall can
| be seen in Figures 2, 3, and 4 for flap angles 0,
| 15, and 40 degrees. The graphs also present the
| points where the stick shaker operates and shows
| the 7 percent margin required by Civil Air Regulations
| for adequate stall warning. In all cases, except at 30
| and 40 degree flaps, initial buffet will occur at a
| speed higher than the 107 percent stall speed
| requirement. However, initial buffet is never less
| than 4 percent above stall speed even at 40° flaps.
| Since the reference landing speed (Vref) is 130
| percent of the stall speed, there is adequate speed
| margin for landing."
|
| Besides flying the line in the -200 series from 1986-
| 1991, I taught the -100 series back in 1977-78.
|
| Yes, there were a couple of early landing accidents
| attributed to excessive sink rates and the fix was to
| change the technique that the pilots were using.
|
| Would you like a lesson on the flap/speedbrake interaction
| and the sink rates that it causes?
|
| Bob Moore
| ATP B-707 B-727 L-188
| PanAm (retired)