TM 1-1520-240-10
7-1-2
b. Calculated Data. Data based on tests, but not on
flight test of the complete aircraft.
c. Estimated Data. Data based on estimates using
aerodynamic theory or other means but not verified by
flight test.
7-1-6. Specific Conditions.
The data presented is accurate only for specific condi-
tions listed under the title of each chart. Variables for
which data are not presented, but which may affect that
phase of performance, are discussed in the text. Where
data is available or reasonable estimates can be made,
the amount that each variable affects performance will be
given.
7-1-7. General Conditions.
In addition to the specific conditions, the following gener-
al conditions are applicable to the performance data.
a. Rigging. All airframe and engine controls are
assumed to be rigged within allowable tolerances.
b. Pilot Technique. Normal pilot technique is
assumed.
c. Aircraft Variation. Variations in performance
between individual aircraft are known to exist: however,
they are considered to be small and cannot be accounted
for individually.
d. Instrument Variations. The data shown in the
performance charts does not allow for instrument
inaccuracies or malfunctions.
e. Airspeed Calibrations. The airspeed calibration
chart presents the difference between indicated airspeed
(IAS), and calibrated airspeeds (CAS) for different flight
conditions.
f. Except as noted, all data is for clean configuration
(all doors installed, without armament).
g. Types of Fuel. All flight performance data is based
on JP-5 fuel. The change in fuel flow and torque
available, when using JP-4, JP-8, Aviation gasoline or
any other approved fuels, is insignificant.
7-1-8. ERFS II Performance Data.
Use of the performance data will enable the operator to
receive the maximum safe utilization of the ERFS II and
FARE kit.
7-1-9. ERFS II Tank Capacity.
The capacity of the ERFS II tank using pressure refueling
is 805.5 US gallons. If filled using gravity refueling, the
capacity is 825.5 US gallons (In both cases 5.5 GALS will
be unusable).
7-1-10. Amount of Unusable Fuel.
7-1-11. Fuel Transfer Rate.
The amount of unusable fuel in each of the ERFS II tanks
is 5.5 US gallons of JP-8.
The rate at which fuel is transferred from the ERFS II
tanks to the helicopter main tanks is 23 GPM.
7-1-12. FARE Transfer Rate.
The FARE kit pump is rated at 120 GPM. However, the
configuration of the FARE fuel transfer hose assembly
affects this transfer rate. Pressure losses across cou-
plings, filters, and nozzles reduce the flow rate below the
rated value. The rate at which fuel is transferred from the
ERFS II tanks using the FARE pump and standard con-
figuration of the FARE fuel transfer hose assemble is 84
to 88 GPM.
7-1-13. Performance Discrepancies.
Regular use of this chapter will allow you to monitor in-
struments and other aircraft systems for malfunction by
comparing actual performance with planned perfor-
mance. Knowledge will also be gained concerning the
effects of variables for which data are not provided,
thereby increasing the accuracy of performance predica-
tions.
7-1-14. Definitions of Abbreviations.
Capitalization and punctuation of abbreviations varies,
depending upon the context in which they are used. In
general, full capital letter abbreviations are used in text
material, charts and illustrations. Periods do not usually
follow abbreviations; however, periods are used with ab-
breviations that could be mistaken for whole words if the
period were omitted.
