SUPPLEMENTARY FLIGHT PROCEDURES AND EMERGENCY PROCEDURES
A100. FUEL, POSITION REPORTS
As in Contact Stage, check and report pounds of fuel remaining in each wing every 15 to 20
minutes during the flight. Include with your report an estimated position from the navigational
facility in use, e.g., "Instruments checked, fuel quantity, 300 left, 280 right, on the Crestview
270º radial at 10 DME."
A101. GROUNDSPEED CALCULATIONS
A knowledge of groundspeed is essential to you as a pilot. Knowing your groundspeed will
enable accurate determination of ETAs and facilitate fuel planning. Comparing true airspeed and
groundspeed gives you wind information. All methods of determining groundspeed are similar
in that they measure the amount of time required to cover a known distance or determine the
distance traveled in a known amount of time. When tracking on a TACAN radial, the DME may
be used to determine distance covered and the aircraft clock can keep track of elapsed time. In
such a case, groundspeed is determined as follows:
Start the clock's sweepsecond hand and note DME.
After six minutes have elapsed note DME and determine distance flown.
Multiply this distance by ten. The result is groundspeed in knots.
More accurate groundspeed checks can be obtained by timing for periods greater than six
minutes. (For more than six minutes, the multiplier in step c. must be changed.)
At 150 knots indicated airspeed (at low altitudes), you are
traveling at approximately 2½ miles per minute, no wind. This
fact allows you to make reasonably accurate ETAs until the refined
procedures above can be accomplished.
Most Air Route Traffic Control Centers will be able to
provide you with a groundspeed readout if you are in radar contact.
This information can be used to check your own calculations and
also those derived from GPS.
A102. TRUE AIRSPEED CALCULATIONS
You are familiar with the procedures for computing true airspeed as taught in IFR ground school.
True airspeed is important mainly for flight planning. However, in the air it is also mandatory to
report any true airspeed change of 10 knots or 5%, whichever is greater. Your proficiency in
true airspeed calculation will be checked periodically.
SUPPLEMENTARY FLIGHT PROCEDURES AND EMERGENCY PROCEDURES A-1