HYDRAULIC LEAKS, THE PROBLEMS AND BACKUP SYSTEM

The Problems Due To Hydraulic Failure and The Evaluation of the Backup System



HYDRAULIC FAILURES, PROBLEMS AND BACKUP SYSTEM

Introduction

In the hydraulic technology we transmit and control forces and velocities by transmitting and controlling pressure and flow. In nearly every kind of technology we use hydraulic drive and control techniques. The hydraulic systems in a plane do have the tendency to fail and stop working, in these situations the pilots use some techniques to control the plane and land it to safety. Asymmetry thrust is one of the most used techniques which are used by pilots to control the plane in event of failure. This report analyzes the problems created by the failures of the hydraulic system of a twin engine plane, and the alternatives the pilot has in this case.

POTENTIAL PROBLEMS RESULTING IN A HYDRAULIC FAILURE When a total hydraulic failure occurs in an aircraft in flight, all the systems of an aircraft are isolated from the cockpit system. The pilot may have very little control over the plane then. Usually the failure of one hydraulic system is not very dangerous because there are many systems, which are not dependent on the other system, and a pilot to control a plane can use any of these systems.

The potential problems, which could arise due to hydraulic failure, are:

1.Hydraulic failure may cause the landing gears to fail or not even work properly. The main, centre, nose gear and doors are controlled through a electronic mechanism, by the Landing Gear Control & Interface Unit (LGCIU) and are controlled by the GRN system. The main gear is a twin tandem bogie, 4-wheel system with oleo pneumatic shocks; the wheels have an anti-skid. The shock is shortened into the main leg during retraction. A hydraulic pitch trimmer damps the bogie motion and tilts the gear after TO. The centre gear is a 2-wheel assembly with a 2 stage o/p shock but no brakes. The nose gear is a 2 wheel assembly with an o/p shock strut and nose wheel steering. Doors attached to the gear itself are mechanically actuated by the gear and close on retraction. All other doors are hydraulically operated and close after gear extension and retraction. If GRN fails, the gear can only be extended by gravity. (Feldmann & George, 2001, Pp.120)

2.Hydraulic failures may involve failure of flaps. In an aero plane, flaps are the moveable surfaces near the edge of the wing. They are usually very big and are placed right next to the wing, both the flaps are activated at the same instant and special care is taken that that the flaps move together instantly otherwise it will create a rolling effect more like the ailerons.

The use of flap in an aero plane increases both the lift and the grag of the plane wing. The major use of a flap is in the landing of the aircraft, these flaps allow the plane to lad smoothly without letting the speed get out ...