(3)
Place axle jack under right main gear and slowly raise jack to compress shock strut to
5.00 inches from full extension.
(a)
Check that air sensing test light on landing gear electrical module goes off before the ground sensing test light.
(b)
Check that control lever is prevented from being placed in UP position when air sensing test light is off.
(c)
Check that ground sensing test light on landing gear electrical module goes off by the time shock strut is compressed 5.00 inches from full extension.
(4)
Continue to compress shock strut and check that results listed in step (3) remain the same for all additional shock strut compression.
(5)
Slowly lower jack to extend shock strut and check that ground sensing test light comes on before the air sensing light comes on.
(6)
Continue to allow shock strut to extend. Check that control lever remains latched until shock strut reaches 1.75 inches from fully extended position.
(7)
Continue to allow shock strut to extend by small increments and check that air sensing test light comes on and control lever can be placed in UP position without use of override trigger by the time shock strut reaches 0.50 inch from fully extended position. Results should remain the same when shock is fully extended.
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Jun 20/92 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 32-09-200 Page 503
D. Restore Airplane to Normal Configuration
(1)
Remove axle jack from main gear.
(2)
Lower airplane and remove jacks (Ref Chapter 7, Jacking Airplane).
(3)
Determine if there is further need for electrical power on airplane; if not, disconnect external electrical power supply.
(4)
Service right main gear shock strut (Ref Chapter 12, Main Landing Gear Shock Strut Servicing).
Landing Gear Safety Sensors Adjustment 501
32-09-200 Figure 501 (Sheet 1) Feb 01/76
Page 504
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.
E80210
549 Landing Gear Safety Sensors Adjustment
Sep 01/02 Figure 501 (Sheet 2) 32-09-200
Page 505
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.
MAIN GEAR - DESCRIPTION AND OPERATION
1. General
A. Each main gear consists of a trunnion link, a shock strut, a drag strut, torsion links, a damper, a side strut, and a reaction link. (See figure 1.) In addition, the right main gear carries ground speed brake operating rods and cable.
B. The shock strut assembly is attached to the trunnion link by a pin joint and the two are mounted between the rear wing spar and a trunnion support beam. The shock strut is charged with oil and compressed nitrogen to provide a shock absorbing medium. Main gear axles and the shock strut inner cylinder are machined from a one piece forging. Replaceable sleeves are assembled over axles to provide a mounting for wheel bearings and protect axles from damage. The reaction link is connected to the shock strut and to the upper end of the side strut. Refer to 32-32-0 for information on main gear extension and retraction.
2. Main Gear Trunnion Link
A. The main gear trunnion link provides the forward pin of the hinge for main gear retraction and transmits landing gear loads from the drag strut into airplane structure. The trunnion link is mounted between the shock strut and the rear wing spar. (See figure 2.) The aft end of the link is pinned to the shock strut and the forward end pivots in a spherical bearing mounted in the rear wing spar. The top end of the drag strut is attached to a lug on the underside of the link, near the spherical bearing. A pushrod from a bracket on the underside of the link operates a shock strut door hinged to the wing. The door covers part of the shock strut aperture in the wing when the gear retracts. A swivel fitting for hydraulic lines is mounted on top of the link. The trunnion link is machined from a high tensile steel forging.
B. The trunnion forward bearing bolt is designed to fail if the landing gear receives a severe impact, thus minimizing damage to structure.
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3. Main Gear Shock Strut
A. The main gear shock strut is the primary supporting member of the landing gear. The shock strut is made of steel and consists of an inner cylinder, an outer cylinder, an orifice support tube and a metering pin. (See figure 3.) The orifice support tube is attached to the top of the outer cylinder. Upper and lower bearings provide sliding surfaces and locate the inner cylinder concentric with outer cylinder. A snubber valve located below the upper bearing provides control of shock strut rebound. A packing adaptor with annular grooves is installed between the lower bearing and a spacer. A channel seal in the packing adaptor is in contact with the inner cylinder. An O-ring between two backup rings makes contact with the outer cylinder. The channel seal and the O-ring provide an air-oil seal between the cylinders. Annular grooves in the lower bearing are used to store spare O-rings. The spare rings in the lower bearing can be used to replace active seals without removing the inner cylinder. The shock strut is attached to airplane structure by an extension on the outer cylinder and by the trunnion link. The lower end of the shock strut is held in position by the side strut and the drag strut.
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