gear and brakes

Flight Operations and Safety Procedures

  • General Flight Guidelines
      - Upon being knocked down, maintain at least one power lever at flight idle.
      - Awareness of radar altimeter is crucial, especially at critical heights like 500 feet and below.
      - If flaps are up and one power lever is at idle, a low gear warning will trigger at 500 feet.
      - No flaps and one power lever in idle will lead to a low flaps warning.
      - Confirmation of landing gear existence is mandatory when below 500 feet using radar altimeter.
  • Operational Procedures
      - Ensure to review aircraft systems in approach briefing before landing.
      - Take note of any inoperative systems impacting flight operations, including emergency equipment.
      - Emergency systems such as stick pusher and TCAS will be inoperative at altitude below 500 feet.

Flight Control Systems

  • Wheel Steering System
      - The wheel steering is part of the blue hydraulic system providing directional control.
      - Includes a bobbin valve and steering feedback mechanism similar to automotive systems.
        - When the wheel is turned, feedback mechanism engages to manage hydraulic pressure.
      - Protections are in place to prevent jammed nose wheel due to hydraulic failure when the landing gear is up.
        - Includes solenoid valve that isolates the blue system pressure when weight is off wheels.
        - Self-centering springs and mechanical swivel valves provide redundancies in the control system.
  • Incident Reference
      - An incident involving American Airlines flight from O'Hare to Charleston illustrates mismanagement.
        - The ramp crew mistakenly placed chocks in the wheel well leading to gear issues during taxi and takeoff.
        - Crew managed a safe landing despite failure to deploy the right main gear.

Brake Systems and Safety Features

  • Brake Indicator Lights
      - An FAA-required brake light activates for actual gear unsafe conditions.
      - The indicator does not display during transit but activates when an unsafe condition is detected, like gear not being fully deployed.
  • Override Functions and Modifications
      - Retract override switch available on some modified aircraft allows gear retraction even if the system inhibits retraction on the ground.
  • Anti-Skid System
      - Anti-skid is inhibited below 10 knots to prevent jerking during taxi operations.
      - The brake pressure becomes active only at speeds greater than 35 knots to prevent tire blowouts upon touchdown.
      - The anti-skid system kicks in when speed reaches 23 knots, releasing brake pressure from the slower rotating wheel to ensure safety.
  • Touchdown Protection
      - Touching down with brakes applied will inhibit brake pressure until speed increases to 35 knots to prevent tire damage.
      - In the event of high energy landing scenarios, the brake system designed to prevent tire explosions by venting pressure if the brake temperatures exceed critical limits.

Temperature Management Procedures

  • Fusible Plugs and Safety
      - Each wheel contains fusible plugs, which soften and release nitrogen pressure at temperatures exceeding 177°C (350°F) to prevent tire explosions.
      - Brake temperatures are monitored via sensors; 160°C is the threshold for brake hot warnings, with fuse plugs ensuring safety above 177°C.

Operational Procedures on Emergency Scenarios

  • Parking Brake Protocols
      - The emergency parking brake has a distinct notch; exceeding one centimeter past this can lead to catastrophic failure of tires and rims.
      - Safety protocols stress caution when using the emergency brake, especially in unexpected scenarios such as hot brakes or high-speed landings.
  • Preparation for Landing
      - Utilize data to assess required landing distance during approach adjustments; calculations must account for any inoperative brake systems.

General Operations and Preparation for Checkrides

  • Training and Checkride Preparations
      - Importance of detailed knowledge of systems for oral examinations and practical checkrides emphasized.
      - Review protocols in case of dual system failures to ensure safety and compliance with operational protocols.
  • Weight and Balance Assessment
      - Conduct thorough weight and balance checks prior to flights, especially in conjunction with safety briefings.

Final Operational Considerations

  • Dealing with Altitude and System Failures
      - In case of systems failure such as blue pressure loss, assess and adjust as required for safe landings.
      - Max tire speed must be maintained, and typical operational ranges should be adhered to carefully.
  • Continuous Review and Update of Procedures
      - Regular reviews of standard operating procedures (SOPs) stay updated for all pilots to ensure robust handling of potential issues.