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Pilot Stick Sensor, Primary Flight Controller (PFC)

Technical Information

Catalogue No: C0792
Category: Flight Control
Object Type: Inceptor
Object Name: Pilot Stick Sensor, Primary Flight Controller (PFC)
Part No: 15-024-01
Serial No: 00005
Manufacturer: GEC Avionics
Division: Unknown
Platform(s): A-12 Avenger II 
Year of Manufacture: circa 1990
Dimensions:
Width (mm):
175 
Height (mm):
330 
Depth (mm):
378 
Weight (g):
7,340 
Location: Main Object Store
Inscription(s):

PFC DCU-292/A
Contract N00019-88-C-0050
Dsgn Act K0656
PN 15-024-01
TM
Mfr K0656
NSN
────────────────
RAS 00005
A3Q90

Notes:

The manufacturer has been identified by:
(a) The years of the A--12's development;
(b) CAGE code K0656 meaning the Rochester site and
(c) The Rochester company name history.

A passive sidestick only provides back pressure forces when it is deflected, by mechanical phenomina such as springs, dampers, and friction. It is passive in that it cannot be made to move other than by pushing against it, it never moves by itself. Passive pilot controls use position sensors to send electrical signals to the fly-by-wire system.

The amplitude of the pilot's stick inputs are electrically measured and generated as control signals to the aircraft flight control computer. A complex spring/damper system, provides the pilot with force feel characteristics and ensures that the stick is reset to its neutral position without noteworthy overshoots when released by the pilot.
The stick has two-axes and provides both pitch and roll electrical command signals. Typically, four independent electrical pick-offs are provided for each axis of control in order to meet the failure survival requirements. The damper provides a smooth feel to the stick movement the spring and damper combination acting as a low pass filter on the stick movement. A small breakout force is required to displace the stick from the central position in pitch and roll. Roll control is a simple linear spring characteristic, Pitch, however requires a step increase in force at larger stick aft deflections and the spring rate is also increased so that larger forces have to be exerted when commanding high 'g' manoeuvres.

These traditional systems use mechanical inceptors, which cannot affect the feel of the stick in real time, so changes to the flight envelope of the aircraft cannot be fed back to the pilot as cues, leading to no situational awareness through the inceptor feel, such as excessive bank angle or stall.

 

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