Airplane Zoning system

Airplane Zoning system

A. The "zoning" process employs a three-digit numbering system to identify the areas into which the airplane has been divided and subdivided. The first digit identifies the large areas of the airplane, called "major zones" (upper fuselage, wings, etc.). Each major zone is divided into "sub-major zones" (flight compartment, etc.), identified by the second digit. Sun major zones are broken down into "zones" (radome, etc.), identified by the third digit.

B. Zone numbers run preferentially from inboard to outboard, front to back, and bottom to top. Wherever applicable, one digit of the zone number will indicate left or right zones by using an odd number for the left side and an even number for the right side. Zones that straddle the centerline are assigned an odd or even zone number.

C. The zones will be defined, wherever possible, by actual physical boundaries, such as wing spars, major bulkheads, partitions, control surfaces, etc. Individual zone numbers will be assigned to major structural components, such as passenger and cargo doors, landing gears, elevators, flaps, ailerons, etc. The area enclosed by the wing-to-fuselage fillets will have individual fuselage zone numbers. The center wing area within the fuselage and areas between the wing and fuselage floor will have fuselage zone numbers.

D. Zone boundaries will enclose related structures, such as door jambs; that is, a jamb for a specific door will not be split by a zone boundary. A unit or component mounted on a zone boundary will take its zone number from the zone in which it is removed.

1.7.3 Major Zones: Major zones are as follows (Ref. Figure 1.2):

                                       

(i) 100 LOWER FUSELAGE:      From station 239 (including radome) to station 2007 aft pressure bulkhead, below fuselage floor, including wing-to-fuselage files and center wing.

(ii) 200 UPPER FUSELAGE:     From station 275 forward pressure bulkhead to station 2007 aft pressure bulkhead, above fuselage floor, including area above nose gear wheel well and area above center wing and main gear wheel well.

(iii) 300 EMPENNAGE:            Fuselage aft of station 2007, horizontal stabilizer, including center section, elevator, aft engine inlet duct, vertical stabilizer, and rudders.

(iv) 400 POWERPLANT AND PYLON:          Includes nacelle doors.

(v) 500 LEFT WING:                                    Includes control surfaces.

(vi) 600 RIGHT WING:                               Includes control surfaces.

(vii) 700 LANDING GEARS AND DOORS.

(viii) 800 DOORS:                                        Passenger and cargo.

Figure 1.2: Major zones of a typical aircraft

Submajor Zones: Major zones are subdivided into submajor zones. For example, some of the submajor zones of major zone 100 are as follows (Figure 1.3):

110    RADOME, AVIONICS COMPT, NOSE WHEEL WELL AND AIR-COND. COMPTS

120    FORWARD CARGO COMPT, AND COMPT, TUNNELS

130    CENTER ACCESSORY COMPT

140    CENTER WING, BELOW CENTER WING AND MAIN GEAR WHEEL WELLS/

150    LEFT AND RIGHT FUSELAGE TO WING FILLET.

Figure 1.3: Example of a sub major zone (110) 

Zones: Each sub-major zone is again divided into zones. For example, some of the zones of Submajor Zones 110, 120 and 130 are as follows (Figure 1.4):

111    RADOME COMPT

112    AVIONICS COMPT

121    FORWARD CARGO COMPARTMENT FORWARD SECTION LEFT TUNNEL

122    FORWARD CARGO COMPARTMENT FORWARD SECTION RIGHT TUNNEL

123    FORWARD CARGO COMPARTMENT FORWARD SECTION

131    CENTER ACCESSORY COMPT. LEFT

132    CENTER ACCESSORY COMPT. RIGHT SIDE

Figure 1.4: Example of zones (131, 132)