AIRCRAFT STATION IDENTIFICATION SYSTEM

AIRCRAFT STATION IDENTIFICATION SYSTEM

There are various numbering systems in use to facilitate location of specific wing frames, fuselage bulkheads, or any other structural members on an aircraft. Most manufacturers use some system of station marking; for example, the nose of the air­craft may be designated zero station, and all other stations are located at measured distances in inches behind the zero station. Thus, when a blueprint reads "fuselage frame station 137," that particular frame station can be located 137 in. behind the nose of the aircraft. A typical station diagram is shown in Figure 1.5.

To locate structures to the right or left of the center line of an aircraft, many manufacturers con­sider the center line as a zero station for structural member location to its right or left. With such a system the stabilizer frames can be designated as being so many inches right or left of the aircraft center line.

Figure 1.5: Fuselage stations.

The applicable manufacturer's numbering system and abbreviated designations or symbols should al­ways be reviewed before attempting to locate a structural member. The following list includes loca­tion designations typical of those used by many manufacturers.

Fuselage stations: These stations (Fus. Sta. or F.S.) are numbered in inches from a reference or zero point known as the reference datum. The reference datum is an imaginary ver­tical plane at or near the nose of the aircraft from which all horizontal dis­tances are measured. The distance to a given point is measured in inches paral­lel to a center line extending through the aircraft from the nose through the center of the tail cone. Some manufacturers may call the fuselage station a body sta­tion, abbreviated B.S.

Buttock line or butt line (B.L.): BL is a width measurement left or right of, and parallel to, the vertical center line.

Water line (W.L.): WL is the measurement of height in inches perpendicular from a horizontal plane located a fixed number of inches below the bottom of the air­craft fuselage.

Aileron station (A.S.): AS is measured out­board from, and parallel to, the inboard edge of the aileron, perpendicular to the rear beam of the wing.

Flap station (F.S.): FS is measured perpen­dicular to the rear beam of the wing and parallel to, and outboard from, the in. board edge of the flap.

Nacelle station (N.C. or Nac. Sta.): NC is measured either forward of or behind the front spar of the wing and perpendic­ular to a designated water line.

In addition to the location stations listed above, other measurements are used, especially on large aircraft. Thus, there may be horizontal stabilizer stations (H.S.S.), vertical stabilizer stations (V.S.S.) or power plant stations (P.P.S.). In every case the manufacturer's terminology and station lo­cation system should be consulted before locating a point on a particular aircraft.