Chapter 5 Operating Limits And Restrictions; General; System Limits - Beechcraft C-12C Operator And Technical Reference Manual

5-1. PURPOSE.
This chapter identifies or refers to all important
operating limits and restrictions that shall be observed
during ground and flight operations.

5-2. GENERAL.

The operating limitations set forth in this chapter
are the direct result of design analysis, tests, and
operating experiences. Compliance with these limits
will allow the pilot to safely perform the assigned
missions and to derive maximum utility from the
aircraft. Limits concerning maneuvers, weight, and
center of gravity are also covered in this chapter.
5-5. INSTRUMENT MARKINGS.
Figure 5-1 illustrates instruments that display
operation limitations.
color coded on the instrument faces. Color coding of
each instrument is defined in the illustration.
5-6. INSTRUMENT MARKING COLOR CODES.
Operating limitations and ranges are illustrated
by the colored markings that appear on the dial faces
of engine, flight, and utility system instruments. Red
markings indicated the limit above or below which
continued operation is likely to cause damage or
shorten life. The Green markings indicate the safe or
normal range of operation.
indicate that the range of the operation covered by the
instrument requires special attention.
permissible in the yellow range, but should be avoided.
White arcs on the airspeed indicator indicate the flap
operating range. The Blue marking on the airspeed
indicator indicates best rate of climb with one engine
inoperative, at maximum gross weight, forward gross
loading, i.e., sea level standard day conditions.
OPERATING LIMITS AND RESTRICTIONS
Section I. GENERAL
Section II. SYSTEM LIMITS
The operating limitations are
The Yellow markings
Operation is
CHAPTER 5
5-3. EXCEEDING OPERATIONAL UNITS.
Anytime an operational limit is exceeded, an
appropriate entry shall be made on DA Form 2408–
13–1. Entry shall state the limit or limits that were
exceeded, range, time beyond limits, and any
additional data that would aid maintenance personnel
in the maintenance action that may be required.
5-4. MINIMUM CREW REQUIREMENTS.
The minimum crew required for flight operation is
two pilots. Additional crewmembers will be added, as
required, at the discretion of the commander, in
accordance with pertinent Department of the Army
regulations.
5-7. INSTRUMENT GLASS ALIGNMENT MARKS
Limitation markings consist of strips of semi–
transparent color tape which adhere to the glass
outside of an indicator dial. Each tape strip shall align
to increment marks on the dial face so correct
operating limits are portrayed.
occasionally verify alignment of the glass to the dial
face. For this purpose, some engine instruments that
have limitation markings shall have short, vertical,
white alignment marks extending from the bottom part
of the dial glass onto the fixed base of the indicator.
These slippage marks appear as a single vertical line
when limitation markings on the glass properly align
with reading increments on the dial face. However,
the slippage marks appear as separate radial lines
when a dial glass has rotated.
5-8. PROPELLER LIMITATIONS.
The maximum propeller overspeed limit is
2200 RPM.
indicate failure of the constant speed (primary)
governor. Propeller speeds above 2120 RPM indicate
failure of both primary and overspeed governors.
Torque is limited to 81%, for sustained operation
above 2000 RPM.
TM 1-1510-218-10
The pilot should
Propeller speeds above 2000 RPM
5-1