True Airspeed Calculations

APPENDIX D

T-6A INSTRUMENT NAVIGATION

Head or Tailwind. Compare GS to TAS to determine if there is a head or tailwind.

Assuming TAS is 210, if GS is greater than 3.5, there is a tailwind. If it is less than 3.5, there is

a headwind. To find the magnitude of the winds, take the larger component and add it to 1/2 of

the smaller component to get the total wind velocity.

Wind magnitude = bigger component + 1/2 the smaller

TRUE AIRSPEED CALCULATIONS

You are familiar with the procedures for computing TAS. TAS is important mainly for flight

planning. However, in the air it is also mandatory to report any TAS change of 10 KIAS or 5%,

whichever is greater. Your proficiency in TAS calculation will be checked periodically

throughout the instrument stage.

FUEL MANAGEMENT

Fuel management is accomplished in two phases.

1. Preflight planning. Preflight planning may be accomplished using the jet log fuel plan

taught in IFR ground school. Additionally, refer to the T-6A manual concerning aircraft

performance data. Utilize the performance data section as necessary in your planning.

2. In-flight monitoring and updating. During the flight, check the accuracy of your fuel

planning by comparing the fuel on board with the jet log estimates for enroute fixes. Re-

compute the fuel plan if predicted and actual fuel usage vary significantly. Monitor the fuel flow

indicator and compare it with the predicted flow. Check for fuel splits and take corrective action

as necessary.

If at any point you doubt your ability to reach your destination (or alternate) with required

reserves, inform your IP of the situation and provide a solution. This may include the need to

modify your flight plan or request ATC assistance as necessary.

EMERGENCY FIELD SELECTION

As in VFR flying, a good aircrew always looks for suitable landing fields in the event of an

emergency. Under IMC, factors determining field suitability include approach availability,

lighting (if at night), runway length, and availability of maintenance services (depending on the

urgency of the situation). The IFR enroute chart depicts those aerodromes with a DoD published

IAP in dark blue. The chart also gives field elevation, runway length, and lighting information.

To further determine whether the approaches are compatible with your NAVAIDs you should be

aware of the suitable fields that lie along your intended route of flight. If an emergency occurs,

after taking the immediate action prescribed by NATOPS, contact ATC with your situation and

intentions. If necessary, ATC can assist in selection of and navigation to the nearest suitable

field. Performing accurate operations checks can lead to early detection of potentially large

problems and help to keep them smaller and manageable.

D-2 SUPPLEMENTAL AND EMERGENCY PROCEDURES