Obtaning Weather Enroute

CHAPTER THREE

RADIO INSTRUMENTS

Mentally move the line to the center of the BDHI.

Read the heading to the target fix.

The key to this procedure is in learning to visualize the location of the aircraft and the "target"

fix on the compass card of the BDHI. The following steps will aid in developing this ability:

Envision the TACAN station at the center of the compass card. The compass card is merely a

compass rose around the station. The fix having the greater distance is always established on its

radial at the outer edge of the compass card. The remaining fix is established along its radial at a

distance from the center of the card proportional to the distance represented by the outer edge of

the compass card. Follow these steps:

Determine the general direction and turn toward the target fix.

Establish the fix with the greater distance on the edge of the card at its radial.

Establish the remaining fix along the fix radial at a proportionate distance.

4. Connect the two fixes with an imaginary line or with the aid of a pencil or other straight

edge. Move the "line" to the center of the compass card so that it is parallel to the original line.

Read the no-wind heading at the point where the moved line crosses the compass card.

NOTE

Always read direction from the aircraft position (tail of the needle)

to the desired fix. Turn to this heading and apply wind correction.

6. Repeat the entire procedure while en route to the target fix. Remain alert to repeated

corrections in the same direction, which would be indicative of a crosswind.

OBTAINING WEATHER ENROUTE

Enroute weather is available from a number of sources, including Flight Service Stations and

Pilot to METRO Services (PMSV). Military aircrews most commonly use PMSV services.

OPNAVINST 3710.7, par. 1.2.4 states that "The procedures, special notices, and instructions

contained in the FLIPs and NOTAMS are mandatory for all pilots flying naval aircraft." This

means the correct way to obtain terminal weather information is to "advise the

forecaster/observer of ETA when terminal weather is requested," in accordance with FLIP Flight

Information Handbook, Section C. Since weather reports and forecasts, as well as aircraft flight

plans, are all in UTC (ZULU) time, an enroute request for terminal weather would sound like:

"Cairns METRO, Rocket 205, request the forecast for Navy Meridian at 1730 ZULU, and the

forecast for Maxwell Air Force Base at 1830 ZULU."

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RADIO INSTRUMENTS