MANILA, Philippines - The Civil Aviation Authority of the Philippines (CAAP) posted in their bulletin board that they are offering a one-year contract worth P40 million for a flight check aircraft to calibrate some 118 navigational aids (navaids) installed nationwide, CAAP source said.
A flight check aircraft is a specially designed airplane, full of devices to calibrate the navaids every six months to make sure they are beaming the correct signals for safe navigation.
CAAP maintains the following navaids: 19 DVOR, a combination of Distance Measuring Equipment (DME) and Very High Frequency Omni Directional Range (VOR); eight regular VOR; 15 non-directional beacons; 16 Instrument Landing System (ILS) with localizer; 15 ILS with Global Positioning and 45 DME.
The CAAP leases a foreign flight check aircraft to calibrate several navaids, sometimes costing P3 million to P5 million when their own flight check plane is under maintenance.
The last time the agency needed one it rented from a New Zealand company to perform the flight checks for a week.
Because of the high cost involved, the CAAP has its own flight check aircraft, a twin-engine Beechcraft King Air.
However, the plane has been out of commission for years after its two engines needed overhauling, the CAAP said.
The engines were eventually repaired in India at a cost of P43 million, but there are still some problems that should be fixed before they could be made operational.
Alger Ramo, a senior airport ramp controller, said that like any electronic equipment, navaids are subject to the changing weather; lightning, thunderstorms and constant use – they are on the air 27/7 – and they often get misaligned or deviate from their setting.
Improperly aligned signals emitted by a navaid could lead an aircraft away from established air routes, which could spell disaster if not corrected on time, Ramo added.
On the other hand, airplanes could also fail to be brought into a proper alignment with the runway during instrument landing approaches if the ILS signals are incorrect.
There are several types of navaids that the CAAP maintains, providing aid to navigation and landing. They differ only in the accuracy and the availability of signals they emit within a given area.
Clark, Subic and the Mactan-Cebu international airports maintain their own navaids. These airports are designated alternate airports.