X. Gear problems

Normal operation:

Hydraulic liquid is pumped into the gear actuating cylinder which drives the mechanical release of the landing gear. To withdraw landing gear, hydraulic liquid is extracted from the cylinder, retracting the landing gear.

Gear problems:

Electrical problems: if the pump cannot be activated none of the system is going to work.

Hydraulic problems: without hydraulic pressure, the gear actuating cylinder will not power the lowering mechanism.

Mechanical failure: the rest of the system may work but the actual mechanism fails to operate.

Expect:

• Manual gear extension, specialist advice may be required.

• Low pass of tower for gear inspection by specialist engineering personnel.

• No gear or only partial gear deployment.

Instructions:

Drag the binoculars over the tower window to view examples of what to expect.

Expect:

• Runway blocked after landing.

• The aircraft may skid off the runway.

• Taxiway may be blocked after clearing runway.

Expect:

• GO AROUND.

• Missed approach procedure should be followed.

ATC

In event of gear problems, remember:

Follow the ASSIST code of practice

A ‘Acknowledge’ – S ‘Separate’ – S ‘Silence’ – I ‘Inform’ – S ‘Support’ – T ‘Time’

(See the ASSIST panel on the bottom left for further information).

• Clear the runway according to local instructions.

• Keep the safety strip clear.

• Check if the towing equipment is on standby.

ATC should also prepare for a LOW PASS of the aircraft to allow a visual inspection of the landing gear and the area around it.

• Technical assistance will be required e.g. a specialist engineer or another pilot.

• If dusk is approaching, the visual inspection should be arranged urgently.

• If visibility is bad, the observer should be at the side of the runway.

• If fog prevents visual checking from the ground, observation may be arranged from another aircraft.

If needed:

(This section applies particularly to light aircraft where the pilot may be inexperienced. Commercial pilots will usually already be familiar with these procedures.)

Assist by informing the pilot about:

In case of a manual gear extension not working, the pilot could attempt a g-load-extension whereby a sharp change in altitude is used to force the gear down.

Retracting the gear is impossible after a manual gear release so extra drag should be factored into any ATC calculations.

Having consulted with a specialist engineer, inform the pilot about the aircraft configuration, e.g. gear appears down / gear doors closed.

The pilot could check the bulbs are working on the gear extension indicator. Has the pilot contacted maintenance?

ATC

XI. Hydraulic problems

• The ACFT may have limited manoeuvrability (bank angle / turns).

• The ACFT may have erratic pitch control.

• The ACFT may have limited bank / increased radius of turn / poor maintenance of heating.

• Higher speeds may result.

• Manual gear extension may be required (no retraction possible).