FIGURE 12-1. EXTRUDED TRACK, ANCHOR PLATES, AND ASSOCIATED FITTINGS
EXTRUDED TRACK ANCHOR PLATE Light duty Medium duty Heavy duty Extruded track and anchor plates are available in several different styles and load capacities and will accommodate a wide variety of quick attachment fittings.
SINGLE PIN TYPE SINGLE PIN TYPE
HOLD DOWN FITTINGS CARGO TIE DOWN FITTINGS Adjustable These types of fittings are suitable for litter or berth attachment to the extruded track and anchor plate styles shown above.
These types of fittings are suitable for cargo tie down attachment to the extruded track and anchor plate styles shown above.
DUAL PIN TYPE CARGO TIE FITTINGS 560° Rotation Low profile These types of cargo tie down fittings are of greater capacity than the single pin types and are suitable for use with the extruded track style shown above.
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FIGURE 12-2. MISCELLANEOUS LITTER, BERTH, AND CARGO TIEDOWN FITTINGS
PAN FITTINGS SINGLE STUD FITTINGS Stud & Cargo ring Cargo ring only Stud only Round head Hex head
SINGLE STUD CARGO TIE DOWN FITTING
SINGLE STUD HOLD DOWN FITTINGS Lift to release These types of fittings are suitable for cargo tie down attachment to the single stud fittings or stud equipped pan fittings shown above.
STUD/RING These types of fittings are suitable for litter or berth attachment to the single stud fittings or stud equipped pan fittings shown above.
EYE BOLT These types of fittings are suitable for litter, berth, and/or cargo tie down attachment directly to the aircraft structure.
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FIGURE 12-3. TYPICAL ATTACHMENT OF FITTINGS TO HONEYCOMB STRUCTURES
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FIGURE 12-3. TYPICAL ATTACHMENT OF FITTINGS TO HONEYCOMB STRUCTURES –
CONTINUED
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FIGURE 12-4. INSTALLATION OF UNDERFLOOR SUPPORT FOR EXTRUDED TRACK
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FIGURE 12-5. TYPICAL CARGO TIEDOWN STRAPS AND CARGO NETS
THREE BAR TYPE SLIDE Rigging for easiest adjustment and moderate loads.
applicable When Rigging for maximum load whether slide is joggled or not.
TYPICAL NAS STRAP ASSEMBLY Available with various types of end hardware and up to 5000 capacity.
TENSIONING SLIDE Used to preload cargo tie down straps.
Handhold
CARGO BARRIER NET
CARGO TIE DOWN NET Commonly used to restrain bulky or composite cargo.
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c. Load Factors.
(1) Use the load factor established by the aircraft manufacturer for type certification as the basis for substantiating the cargo tiedown devices and attachments to the aircraft structure. Refer to the applicable operating rules for any additional load factor requirements if the aircraft is to be used for air taxi or other commercial operations.
(2) The critical load factors to which the installation is to be substantiated are generally available from the holder of the aircraft's typecertificate (TC). When the TC holder is no longer active, contact the certificate management Aircraft Certification Office (ACO).
(3) The maximum loadings are a requirement to which the aircraft manufacturer must adhere. Aircraft manufacturer floor loading limitations take precedence over the load rating of the net, fitting, and tiedown devices.
d. Static Tests.
(1) It is recommended that static testing be conducted on a duplicate installation in a jig or mockup that simulates the related aircraft structure.
Refer to chapter 1, paragraph 3 for static test information.
(2) If the actual installation is used for static testing, inspect both the aircraft and the cargo tiedown device installation thoroughly before releasing to service. Check all members and fittings for cracks, distortion, wrinkles, or elongated holes.
Replace all bolts and threaded fittings that are not inspected by magnetic particle or other acceptable Nondestructive Testing (NTD) inspection process.
Inspect riveted joints for tipped rivet heads and other indications of partially sheared rivets or elongated holes.
(3) All cargo tiedown installations must be tested to the critical ultimate load factor. Refer to chapter 1 of this AC for computation and testing procedures.
(4) When the cargo compartment is separated from the cockpit by a bulkhead that is capable of withstanding the inertia forces of emergency conditions, a forward load factor of 4.5 g may be used. All other applications require the use of a 18 g forward load factor.
(5) Each cargo tiedown fitting installation must be static tested under forward, side, and up load conditions. Individual fittings may be tested by applying a single pull of 12.6 g forward load at an angle of 18.5° up and 9.5° to the left or right (as applicable) of the aircraft longitudinal axis. For example, assuming a 5,000-lb static pull (rating of a typical tiedown fitting) is applied as described and divided by the g load fact or, we find the fitting installation will be capable of restraining a 397-lb load under emergency conditions.
9 g x 1.33 = 12.0
(6) When a cargo-restraining net or cargo container with multiple attachments is used, the static load requirements for each tiedown fitting may be divided equally between the fittings. For example, if the maximum cargo load to be carried is 1,800 lbs and 10 tiedown fittings are to be used, the static load requirement for each fitting is approximately 2,155 lbs.
Example: static load for each tiedown fitting 9 g x 1.33 x 1,800/10 = 2,154.6 Placard individual tiedowns for the maximum weight to be secured.
1204. OPERATING LIMITATIONS, LOAD- ING INSTRUCTIONS, AND PLACARDS.
a. General. Revisions or supplements to the approved portions of the Aircraft's Flight Manual (AFM) regarding markings, placards, or other operating limitations require FAA engineering
approval. Submit the requested changes and supporting data to the local FAA Flight Standards District Office for review and processing.
b. Operating Limitations and Loading Instructions.
(1) Prepare revisions or supplements to the AFM or operating limitations, weight and balance records, and equipment list changes as necessitated by the installation of the cargo tiedown systems.
(2) Provide instructions covering the installation and use of the cargo restraint system. For aircraft that require a fl ight manual, incorporate these instructions as a supplement. On other aircraft, provide a placard that references the appropriate instruction. In the instructions, cover such items as removal and reinstallation of seats or other equipment exchanged for cargo restraint systems, use of cargo nets, barrier nets, number and positioning of tiedown straps, maximum load for each compartment or tiedown area, permissible load per square foot, number of tiedown points allowable per foot of track, and maximum height of the load’s CG above the floor.
c. Placards: Cargo Area Placards. Install placards or other permanent markings to indicate the maximum allowable cargo load and weight per square foot limitation for each cargo area. Placard seat tracks as to number of tiedown points permissible per foot of track. Attach a permanent label or other marking on each cargo net, barrier net, and at cargo tiedowns to indicate the maximum cargo weight that the net or attachment will restrain when installed according to the loading instructions.
1205. AIRWORTHINESS COMPLIANCE CHECK SHEET: CARGO TIEDOWN DEVICE INSTALLATIONS.
a. General. Cargo tiedown device installations that are the same as those made by the manufacturer, or other installations which are already approved, may be accepted without further investigation. On other installations, the following points should be checked to determine that the installation is satisfactory.
b. Applicable Civil Aviation Regulations (CAR).
(1) CAR 3.390 - Seats and Berths.
(2) CAR 6.355 – Seats and Berths.
c. Applicable Title 14 of the Code of Federal Regulations (14 CFR).
(1) Part 21, § 21.303―Replacement and Modification Parts.
(2) Part 23, § 23.785― Seats, Berths, Litters, Safety Belts, and Shoulder Harnesses.
(3) Part 23, § 23.787― Baggage and Cargo Compartments.
(4) Part 27, § 27.785 ―Seats, Berths, Litters, Safety Belts, and Shoulder Harnesses.
(5) Part 27, § 27.787 ―Cargo and Baggage Compartments.
(6) Part 29, § 29.785― Seats, Berths, Litters, Safety Belts, and Shoulder Harnesses.
(7) Part 29, § 29.787 ―Cargo and Baggage Compartments.
d. Structural Requirements.
(1) If the aircraft structure is changed or altered, determine if the original strength and integrity of the structure is retained. (Ref.
AC 43.13-2B, chapter 1 and § 23.561.)
(2) Determine if the extent to which the modification affects the aircraft CG has been evaluated. (Section 23.1589.)
(3) If the equipment is mounted either on the existing structure or on a bracket attached to the Par 1204 Page 142
Par 1205 Page 143 existing structure, confirm that all of the structure (including the bracket, if used) is adequate to support the required loads. (Ref. §§ 23.307, 23.613, 23.561,
25.307, 25.613, 25.561, 27.3 07, 27.613, 27.561,
29.307, 29.613, and 29.561.)
(4) Verify that the equipment is installed so that it does not adversely affect other structures (either primary or secondary).
(5) Confirm that means are provided to permit proper inspections of the installation and related adjacent parts as components. (Ref.
§ 23.611.)
e. Hazards to the Aircraft or Its Occupants. Determine whether the:
(1) Modification creates any projections that may cause injury by human impact.
(2) Fabric used in the modification complies with flame-resistant requirements.
(3) Modifications adversely affect the accessibility of the exits and doors.
f. Detail Design Standards.
(1) Determine if suitable materials are used in the construction, including standard fasteners, and if the method of fabrication will result in a consistently sound structure. (Ref. §§ 21.305,
23.603, 23.605, 23.607, 23.6 13, 27.603, 27.605,
27.607, and 27.613.)
(2) Verify that cargo tiedown devices conform to an acceptable standard.
g. Instructions for Continued Airworthiness. Determine whether:
(1) There are written procedures concerning equipment installation and removal procedures.
(2) Written equipment serviceability requirements are available.
(3) Placards are installed. (Ref.
paragraph 1204.)
(4) Revisions or supplements are provided for the AFM or operating limitations, if required. (Ref. paragraph 1204.)
(5) Written scheduled inspection requirements are available to ensure the aircraft structure, tiedown devices, nets, and fittings are in serviceable condition.
(6) Drawings are available. (Ref.
Figure 12-6.)
h. Recordkeeping. Verify whether:
(1) A maintenance record entry has been made. (Ref. § 43.9.)
(2) The equipment list and weight and balance has been revised. (Ref. Order 8310.6, chapter 1.)
(3) FAA Form 337, Major Repair and Alteration (Airplane, Powerplant, Propeller, or Appliance), and Instructions for Continued Airworthiness have been completed and accepted by the FAA 1206. THRU 1299. RESERVED
FIGURE. 12-6. TYPICAL ALLOWABLE CARGO LOADING DIAGRAM AirDesign report 490-1 sheet E3 1906 Conard Circle prepared by H.Wells Austin, Texas 78734 checked by H. Wells Howard
(512) 266-5250 fax (512) 266-5052 revision G 183 Ibs.
100 Ibs. (45 kg.) 50 Ibs. each- (23 kg.) 28.737 NO LOAD heat duct) ST.A 106,628 TA 73.040 183 IDS STA 53 986 Seat belt fittings- 170 Ibs. each (77 kg.) 5441bs.- (247kg) Page 144 Par 1205