Power Assurance Check - Bell BHT-206L3-FM-1 LongRanger-III Flight Manual

DOT APPROVED
BHT-206L3-FM-1
4-1.
POWER ASSURANCE
CHECK
A Power Assurance Check chart is
provided for the Allison Model 250-C30P
engine (refer to figure 4-l). The Power
Assurance Check chart indicates the
minimum percent torque that must be
available from an engine meeting the
minimum Allison specification. The engine
must develop these values in order to
meet the performance data contained in
this flight manual.
Figure 4-1 may be used to monitor the
engine performance periodically.
To perform power assurance check, turn
off all sources of bleed air, including
ENGINE ANTI-ICING. Establish level flight
at an AIRSPEED of 65 to 105 KIAS or Vne,
whichever is lower.
NOTE
For altitudes above approximately
6000 feet, it may be desirable to
check engine power during IGE
hover prior to takeoff. The Power
Assurance Check chart can be
-
used to accomplish this
procedure. The IGE hover
installation losses require as
much as 2% more power than in
flight. Therefore, the hover power
check may be 2% below that
shown on-figure 4-1, and still
achieve predicted flight manual
performance.
Record the following information from
cockpit instruments:
HP
(Example
10,000 ft)
I
OAT
(Example
25°C)
TOT
(Example
720°C)
TORQUE
(Actual
reading)
Enter Power Assurance Check chart at
observed OAT (Example 25°C), proceed
vertically to intersect indicated TOT
(Example 720°C), follow horizontally to
intersect HP (Example 6000 feet), then drop
vertically to read minimum torque
available (61%).
I
NOTE
If cruise power check cannot be
accomplished below helicopter
65% torque/64 KIAS V,, limitation,
perform check at a higher altitude
or in a stabilized 57 KIAS climb
and subtract 1% from the chart
percent torque reading. For the
previous example, the chart
percent torque would become
96%.
If actual torque indication is the same or
greater than the required chart torque,
engine power equals or exceeds minimum
performance specification and the
performance data contained in this manual
can be achieved.
If actual torque indication is less than the
required chart torque, engine power is less
than minimum specification and all
performance data contained in this manual
Rev. 4 4-3