TM 1-410. Technical Manual, Airplane Structures 1941: Section 15 - Towing, Mooring and Handling

SECTION XV: TOWING, MOORING, AND HANDLING

58. General.-lt is important that operating personnel have a thorough understanding of proper methods of towing, handling, and mooring airplanes. If these operations are not properly performed considerable damage may be done to structural units, cowling. fairing, etc., through creation of unusual stresses in these parts.

59. Towing and handling. - Most military airplanes are equipped with towing rings or similar devices for this purpose, and towlines always will be attached to these devices as shown in figure 64. However, when towing airplanes not equipped with towing rings, the towlines should be attached to the structural unit of the landing gear in such a manner that no damage will be done to any part of the airplane. Length of the towropes should be at least three and one-half times tread of the airplane. In the case of large airplanes equipped with dual wheels on each landing gear leg, a separate source of motive power may be necessary for each landing gear leg to avoid chafing of the wheels, or setting up side stresses on the landing gear structure. During the towing operation there should always be one man in the cockpit to operate the brakes, one or more men as required on the tail wheel steering handle, and a man at each wing tip when maneuvering near hangars, airplanes, or other obstacles. The airplane should never be moved by pushing or pulling on the control surfaces, stabilizers, trim tabs or flaps, but only by means of the reinforced portion of the airplane structure. For lifting the tail all airplanes are provided with reinforced lift points which are marked plainly. Under no circumstances will the tail of an airplane be lifted by means of the horizontal stabilizer.

60. Mooring.-a. Activities having hangars or concrete aprons employ a standard arrangement of permanent anchorage points suited to the types of airplanes being moored. Where no fixed mooring anchorage is provided the standard airplane mooring kit can be used. To use this mooring kit, the anchor rod is screwed into the arrow, and the driving rod slipped over the anchor rod and into the socket of the arrow, as shown in figure 65. The cam on the driving rod must be turned so that the prongs of the arrow will not be spread while driving. If the ground is hard, the hardened surface will first be broken by using a ground-breaking pin which is also a part of the kit. The rod is alined with the point of attachment on the airplane and the arrow is driven into the ground until the driving rod handle is within 3 inches of the ground. The handle is then rotated approximately 90° and the driving rod is given a sharp blow to spread the prongs of the arrow

FIGURE 64.-Towing rings and line attachment.

 The handle is then returned to the driving position and the driving rod assembly is withdrawn from the ground.

b. Arrangement of mooring points for several weight ranges of airplanes is shown in figure 66. Care must be taken to drive the mooring anchor arrows at the proper angle so that the anchor rods will be in line with the points on the airplane to which the mooring ropes are attached. After the driving operation has been completed, the eye assembly is attached to the anchor rod and the mooring rope to the eye assembly. An upward pull on the anchor will f urther spread and set the arrow prongs. With wheel chocks in place in front and back of each wheel the mooring ropes are then secured to the mooring points on the airplane by drawing them sufficiently taut to prevent movement of the airplane. Care should be exercised to avoid strain on structural parts of the airplane, and it should be borne in mind that rain or moisture may excessively tighten the ropes. Rudder and ailerons are then locked in neutral position and the

FIGURE 65.-Mooring anchor.

elevators placed parallel to the ground or as near that position as possible and locked. External control surface locks are used if available, otherwise the controls in the cockpit are used for this purpose. If the airplane is equipped with an automatic pilot, it should be turned to the "On" position as outlined in the instructions pertaining to that equipment.