Emergency Bulletin: Vertical Mast Replacement (Issued November 11, 1992)
Date: November 11, 1992
Re: Customer Notice
Subject: Vertical Mast Replacement - Flight Safety Items Required Before Next Flight
To: All Owners /Operators
From: Harold F. Smith, President
Service Bulletin No. 92-09-01
1. Service revealed incidents indicate a need to accomplish the following modifications to Air Command Gyroplanes as described below;
A. Vertical Mast: Vertical mast, P/N 0013 should be inspected to assure that the single 2" x 2", 6061-T6 mast has been replaced with vertical mast, P/N 0013B, which is composed to two (2) each 1" x 2", 6061-T6 segments placed together to form a 2" x 2" mast with the 2" sides oriented parallel with the longitudinal axis of the airframe. This modification doubles the strength in the longitudinal axis by providing four (4) each 2" faces instead of the original two faces in the monolithic 2" x 2" original structure.
Note 1: All Air Command gyroplanes manufactured by Air Command Manufacturing Inc., of Liberty MO., were equipped originally with the single 2" x 2" mast, P/N N0013. All Liberty manufactured aircraft should be modified with the dual redundant mast comprised of two (2) each 1" x 2" extrusions joined together as described above. This mast is P/N 0013B.
Note 2: All Air Command gyroplanes manufactured by the Daytona Beach Group between September 1990 and April 1992 must be inspected. Air Command gyroplanes manufactured in the Florida facility began with the 2" x 2", vertical mast, P/N 0013, changed later to a 2" x 2" extrusion that was 2" x 2" externally with a center interior wall P/N 0013A. Later versions produced by the Daytona Beach Group were equipped with the dual redundant mast comprised of two each 1" x 2" extrusions joined together as described above. All Air Command gyroplanes manufactured in Florida must be inspected. Airframes with the 2" x 2" single mast with or without the internal third wall must be replaced with the P/N 0013B configuration.
Caution: It is possible that Liberty, MO. manufactured gyroplanes have been previously modified by a former or current owner. Should inspection of the airframe reveal the dual redundant mast is already installed, no further action is required by this service bulletin except routine inspections for serviceability.
B. Joystick: Joystick, P/N 0096 has been replaced with joystick, P/N 0096A. The "A" version has a traditional front pivot forward of the pilot, whereas the original version pivoted under the seat and is commonly known as the "pump stick". All pump stick, under the seat pivoting joysticks, must be replaced with the forward pivoting joystick, P/N 0096A.
Note: Visual inspection of the aircraft will quickly reveal if the joystick pivots under the seat or not. All Air Command gyroplanes manufactured in Liberty, MO., were equipped with the pump stick. The Florida manufactured gyroplanes were manufactured with the pump stick early in the Florida production, and later production units from Florida incorporated the front pivot joystick, P/N 0096A.
C. Horizontal Stabilizers: The flying rudder must be equipped with horizontal stabilizers, kit P/N B0052, to aid stability in pitch. Air Command gyroplanes manufactured in Liberty, MO., generally were not so equipped until late in the Liberty production.
2. Failure to comply with this Emergency Service Bulletin essentially will cause Air Command aircraft not inspected, nor modified as required, to be non-airworthy.