Wednesday 18 February 2015

Marshalling procedure of a Helicopter


Helicopter Receiving Procedure:

  • Select the Parking area.
  • One main marshaller will receive the helicopter.
  • Two side marshaller will place the chocks both sides of the helicopter.
  • Fourth marshaller will place CO2 fire extinguisher near the helicopter engine intake.
 Helicopter Seeing off procedure:

  • Main marshaller will be in front of the helicopter for giving required signals
  • Second marshaller will be with CO2 fire extinguisher near the helicopter engine intake.
  • Main marshaller will give signal for starting the helicopter engine.
  • After starting the engine, taking clearance from pilot, both side marshallers will remove chocks and also CO2 fire extinguisher.
  • Then see off the helicopter.
  • Keep CO2 fire extinguisher and chocks in a safe place.
  • Marshalling signals are identical for day or night operations.
  • During night marshalling, illuminated wands are used instead of bats.



Tuesday 17 February 2015

AIR SUPPLY OF AIRCRAFT




AIR SUPPLY OF  AIRCRAFT



The source of air supply and arrangement of essential components depends on the type of aircraft and air conditioning system employed, but in general one of the methods described below may be adopted.

Engine bleed air
This method is adopted in certain type of turbo jet aircraft in which hot air readily available from main engine compressor is tapped off and supplied to the cabin. Before the air enters the cabin it is passed through appropriate control valves and temperature. Control system to reduce its pressure and temperature.

Auxiliary power units (A.P.U)
Auxiliary power units are employed in many types of transport aircraft. Their purpose being to provide a source of electrical power and pressurized air.



Compressor or Blowers
This method is utilized in some type of turbo jet, turbo propeller and piston engine aircraft, the compressor or blowers being driven by the engines via accessory drive gear boxes or bleed air. Air is drawn in through a ram air intake located in a wing leading edge or an engine nacelle fairing. A filter unit may be provided to protect the blower rotors from foreign matter and to ensure a clean air supply. In order to reduce level of noise, silencers are incorporated in the main supply ducting.

Ground Cart
Mobile air conditioning and heating units are grounded support equipment designed to supply conditioned air to heat or cool aircraft. Such units are capable of delivering a large airflow against static pressure at the end of a flexible duct or into aircraft. Reciprocating engine internal super charge provides the simplest means of cabin pressurization. This is accomplished by ducting air from supercharge to the pistons. Air for cabin pressurization can also be ducted from a turbocharger used with a reciprocating engine.