Landing Gear, Wheels, Brakes and Anti-Skid
Gear configuration
Know the difference between fixed and retractable gear, nose-wheel and tail-wheel layouts, and the purpose of the downlock, uplock and squat switch. Understand that the squat switch prevents gear retraction on the ground and often controls anti-skid or pressurisation logic. Traps include confusing the downlock with the uplock and forgetting that a gear warning sounds with the throttle closed and gear up.
Wheels and tyres
Tyres are rated by ply rating and speed, and must be correctly inflated because under-inflation causes sidewall flexing and heat. Know the role of the tube and tubeless tyre, and the brake disc as a heat sink. Traps include the question of why a tyre should be checked cold and why a hot tyre is not deflated.
Brakes and anti-skid
Brakes may be independent, differential or power brakes. Anti-skid systems use wheel speed sensors and a control unit to modulate brake pressure and prevent a locked wheel. Know that anti-skid does not shorten the stop on a dry runway as much as it preserves control on a wet or contaminated one. Traps include the fact that anti-skid is usually inactive below a low taxi speed.
Worked example
If a wheel locks and the aircraft swerves on a wet runway, the anti-skid should release pressure on that wheel. Rule of thumb: anti-skid protects against skids and loss of directional control, not against aquaplaning, which depends on speed and water depth.