6.1 Landing Gear, Wheels, Tires, and Brakes

Landing Gear Basics: Loads, Pressure, and Ground Risk

Landing gear supports the aircraft during taxi, takeoff, landing, towing, and parking. It absorbs shock, provides directional control, and carries braking loads. The Airframe ACS includes fixed and retractable gear, strut servicing, steering, position warning, brakes, anti-skid, wheels, tires, and safe jacking because these tasks expose people and aircraft to stored energy.

A landing gear inspection starts with the aircraft safely configured. The technician checks the maintenance manual for jacking points, weight limits, gear pins, safety devices, and hydraulic or electrical precautions. Good judgment means not placing a jack under a convenient structural point unless the manual permits it. A stable aircraft is the first condition for a reliable inspection.

Wheel and tire work deserves respect. Aircraft tires may be inflated to high pressure, and a damaged wheel assembly can fail violently. Tires are inspected for cuts, exposed cord, flat spots, weather checking, sidewall damage, tread wear, foreign objects, and proper inflation. Wheels are inspected for cracks, corrosion, security, bearing condition, tie bolts, and evidence of overheating.

Use this inspection list for gear, wheel, tire, and brake scenarios:

• Verify aircraft support, chocking, jacking, and gear safety procedures.
• Inspect gear structure, attach fittings, torque links, drag braces, side braces, and locks.
• Check strut extension, leaks, cleanliness, exposed chrome condition, and servicing records.
• Inspect wheels, bearings, tires, inflation, valve caps, and storage or age concerns.
• Inspect brake linings, discs, calipers, back plates, hoses, fittings, and leaks.
• Check brake operation, parking brake release, pedal feel, dragging, and fluid condition.
• Document defects and do not return the aircraft to service with unresolved safety findings.

Brake problems can be diagnosed by symptoms. A spongy pedal often suggests air in a hydraulic brake system. A dragging brake may come from trapped pressure, contaminated parts, warped disc, incorrect adjustment, or parking brake malfunction. Weak braking can involve worn linings, leaks, air, glazed surfaces, or low fluid. Pulling during braking may indicate unequal brake action or tire condition.

Shock struts also have predictable symptoms. Too much extension, too little extension, leaking fluid, or repeated bottoming requires servicing and troubleshooting. An air-oil strut is not just inflated until it looks right. The proper fluid, extension, pressure, and servicing sequence come from the aircraft data. High pressure strut disassembly without proper depressurization is a serious hazard.

For exam questions, pay attention to whether the situation involves pressure, support, or rotation. The safest answer normally secures the aircraft, relieves or controls stored energy, uses the manual, and inspects the complete system instead of replacing the first visible part.

A useful exam habit is to separate serviceable wear from a condition that changes load carrying ability. A tire near limits, a cracked wheel, a leaking brake line, or a loose torque link may all appear during the same inspection, but each has a different corrective path. The answer that keeps the aircraft secure while tracing the defect to approved limits is the best maintenance judgment.