PPRuNe Forums - View Single Post - A question on B737 manual reversion forces
Old 26th Mar 2014, 16:40
  #4 (permalink)  
CL300
 
Join Date: Jan 2004
Location: Far away from LA
Posts: 1,032
Likes: 0
Received 0 Likes on 0 Posts
Just my 2 cents,
Generally speaking , simulators are just computers with 'triggers' in order to mimic the airplane behavior in some circumstances.
If the checklist calls for green dot for example in order to fly the aircraft without hydraulics, if this first condition is not met, the simulator will not recognize the procedure as per se.
Therefore it is not impossible that following an update of the said software, this specific trigger was misplaced or its tolerance "tighten", making it more difficult to fly.
If the design and certification allows the plane to be flown with the standard control wheel, the forces cannot exceed a published value, laid in CS25 literature.
It is worth a check with the training organization... Humans are human, and do mistakes..

CS 25.671
CONTROL SYSTEMS General
If the functioning of stability augmentation or other automatic or power*operated systems is necessary to show compliance with the flight characteristics requirements of this CS*25, such systems must comply with CS 25.671 and the following:
......
(c) The aeroplane must be shown by analysis, test, or both, to be capable of continued safe flight and landing after any of the following failures or jamming in the flight control system and surfaces (including trim, lift, drag, and feel systems) within the normal flight envelope, without requiring exceptional piloting skill or strength. Probable malfunctions must have only minor effects on control system operation and must be capable of being readily counteracted by the pilot.
(1) Any single failure not shown to be extremely improbable, excluding jamming, (for example, disconnection or failure of mechanical elements, or structural failure of hydraulic components, such as actuators, control spool housing, and valves). (See AMC 25.671(c)(1).)

AMC 25.671(c)(1)
Control Systems – General
To comply with CS 25.671(c)(1) there should normally be –
a. An alternative means of controlling the aeroplane in case of a single failure, or
b. An alternative load path.

would be

From CS25.405........IF boeing had chosen the reversion as secondary controls

Control Limit pilot forces
Miscellaneous: *Crank, wheel, or lever.
( 25.4 + R /76.2 )x 222 N (50lbf), but not less than 222 N (50 lbf) nor more than 667 N (150 lbf)
(R = radius in mm). (Applicable to any angle within 20° of plane of control).

That would fit within your hands on experience..

Last edited by CL300; 26th Mar 2014 at 17:43. Reason: adding CS25
CL300 is offline