User avatar
PacoMartin
Topic Author
Posts: 146
Joined: Sun May 27, 2018 8:18 pm

FAR § 25.203 Stall characteristics.

Sun Jul 14, 2019 10:18 am

Does anyone know what jet prompted this law?
[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as amended by Amdt. 25-84, 60 FR 30750, June 9, 1995]

It seems unlikely that it was the B737 since the first order for that jet was on Feb. 15, 1965.
Any other technical comments would be welcome. I am curious if the B737 MAX is the first design to require something like MCAS to keep in compliance with this regulation.

§ 25.203 Stall characteristics.
(a) It must be possible to produce and to correct roll and yaw by unreversed use of the aileron and rudder controls, up to the time the airplane is stalled. No abnormal nose-up pitching may occur. The longitudinal control force must be positive up to and throughout the stall. In addition, it must be possible to promptly prevent stalling and to recover from a stall by normal use of the controls.
(b) For level wing stalls, the roll occurring between the stall and the completion of the recovery may not exceed approximately 20 degrees.
(c) For turning flight stalls, the action of the airplane after the stall may not be so violent or extreme as to make it difficult, with normal piloting skill, to effect a prompt recovery and to regain control of the airplane. The maximum bank angle that occurs during the recovery may not exceed -
(1) Approximately 60 degrees in the original direction of the turn, or 30 degrees in the opposite direction, for deceleration rates up to 1 knot per second; and
(2) Approximately 90 degrees in the original direction of the turn, or 60 degrees in the opposite direction, for deceleration rates in excess of 1 knot per second.
 
GalaxyFlyer
Posts: 3365
Joined: Fri Jan 01, 2016 4:44 am

Re: FAR § 25.203 Stall characteristics.

Sun Jul 14, 2019 11:16 am

Part 25 and its predecessor CAR 4B go back a long ways. Stall characteristics for non-FBW planes are pretty settled matter. There needs to be a speed stable without stick force lightning in the approach to stall, basically once in trim slowing requires a constant increase in back force. That’s the basic with some exceptions.

Planes have had various “fixes” for any lack of natural buffet or roll off for decades-shakers, pushers, auto trim inputs and the FBW planes have it all in the software.

It’s not a law, it is a CFR and the AMC Advisory Circular goes into more detail. It’s a not a cut and dried process

Who is online

Users browsing this forum: greg85 and 16 guests

Popular Searches On Airliners.net

Top Photos of Last:   24 Hours  •  48 Hours  •  7 Days  •  30 Days  •  180 Days  •  365 Days  •  All Time

Military Aircraft Every type from fighters to helicopters from air forces around the globe

Classic Airliners Props and jets from the good old days

Flight Decks Views from inside the cockpit

Aircraft Cabins Passenger cabin shots showing seat arrangements as well as cargo aircraft interior

Cargo Aircraft Pictures of great freighter aircraft

Government Aircraft Aircraft flying government officials

Helicopters Our large helicopter section. Both military and civil versions

Blimps / Airships Everything from the Goodyear blimp to the Zeppelin

Night Photos Beautiful shots taken while the sun is below the horizon

Accidents Accident, incident and crash related photos

Air to Air Photos taken by airborne photographers of airborne aircraft

Special Paint Schemes Aircraft painted in beautiful and original liveries

Airport Overviews Airport overviews from the air or ground

Tails and Winglets Tail and Winglet closeups with beautiful airline logos