7.17 Jacking and Securing Precautions Flashcards
What are the 4 different type of Hydraulic jacks?
- Axle/bottle jack
- Bipod jack
- Tripod jack
- Quadrupod jack
What is an Axle/bottle jack used for?
Wheel changes
What is a a Bipod jack?
Consists of a hydraulic unit supported by two fixed legs and one adjustable leg. This is used for arc lifts. This is not often carried out.
What are Tripod jacks?
Three legs, equally disposed. Used for vertical lifts
What are Quadrupod jacks?
Four legs, equally disposed. Two fixed and two adjustable to allow for uneven ground.
What 2 jacks are the most common?
- Tripod jacks
- Axle jacks
What common features to Tripod and Axle jacks have?
- Portability
- Hand pump operation
- Self-contained oil reservoir
- Central ram with a hole to accept different jack point adaptors
- Locking collars on the rams
What is used to operate a tripod jack?
Hand pump or compressed air (pneumatically)
What are all tripod jacks equipped with?
Locking collars or hand wheel safety nuts on the rams
How far should the hand wheel safety nut be from the top at all times?
1 inch
What are axle jacks mostly used for?
To lift one landing gear to change a wheel
What must be inspected and tested on a jack?
- Inspect the condition of the jacks.
- Check for any bent or stressed components such as lugs.
- Verify all fluid levels and top off, if needed.
- Check welded joints for any signs of fatigue.
- Inspect for missing or damaged components or parts.
- Examine the condition of the locknuts.
- Check the condition of the pins.
- Never use a jack that is leaking oil (It can collapse under any weight applied).
- Run the jack fully up and down before using it on the aircraft.
Where are most jack points located?
Under the main wing spar with a third jack bar the nose of the aircraft, a 4th jack if used usually supports the empennage
What can the aircraft not be jacked without?
Jacking pads installed
What anchors a light aircrafts empennage to the hangar floor or a weight?
A tie down ring at the rear of the fuselage
What is it important to do while jacking the aircraft?
Raise and maintain the aircraft in a levelled position, jacks must always stay flat on the ground
When axle jacking what must be done to the wheels not being raised?
They must be sufficiently chocked
How do you lower the jack?
By releasing the jacks relief valve
What should happen once the aircraft is on the ground after jacking and why?
Remove jacks immediately as oleos may be stuck in the extended position and suddenly compress, bouncing the aircraft
What are the basic jacking and lowering safety precautions?
- Never put hands between an aircraft jack and the corresponding jack pad.
- Never attempt to align an aircraft jack under an aircraft by pounding or kicking the jack legs. Dented legs can quickly lead to the jack’s collapse.
- Never place hands on top of the jack near the hand wheel safety nuts when lowering an aircraft jack.
- Always lower the hand wheel safety nut(s) after the aircraft jack is fully under the load. Make sure the hand wheel safety nut(s) is fully seated on the jack pad after raising it.
- Always raise and lower the aircraft jack simultaneously, so the aircraft remains level and secure at all times.
- Always use an aircraft tail stand or nose stand, when applicable, for additional stability.
- As with all aircraft maintenance procedures, always wear safety glasses when performing safe jacking techniques.
- Always use hand wheel safety nuts when using airplane jacks. The cast handle will completely surround the pinch point for extra safety.
- When raising or lowering aircraft jacks, always ensure the hand wheel safety nut is 1 inch from the top of the jack.
- Always use aircraft jacks in a level position.
- Always use the appropriate jacking points.
- Always inspect the legs of the aircraft jack to make sure they will not get in the way or otherwise interfere with operations once the aircraft is jacked.
- Check if aircraft stabilisers are required.
- The open air jacking operation is limited if the wind velocity exceeds permissible values which depend on aircraft gross weight and the Centre of Gravity (CG) position.
- During the jacking procedure, no personnel should be allowed in the aircraft.
What issues can result in the aircraft tipping when jacked?
- If there is removed equipment that will change CG, like engines
- If the fuel is not balanced in the tanks
- If there is no tie down etc if needed
- If there are any other activities taking place on the aircraft
What is shoring also known as?
Trestling
What does shoring do?
Relieve the loads on the structure
Where and trestles placed and why?
Usually under the tail in order to support and keep the shape of the fuselage
