曝光台 注意防骗
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precipitation conditions exist, if the aircraft is not airborne within 5 minutes of
the beginning of the final application of anti-icing fluid (time reported), a
pretakeoff contamination check is required. The pretakeoff contamination
check, when required, must also be accomplished within 5 minutes of the
commencement of the takeoff roll.
A pretakeoff contamination check is a close visual check by a qualified flight
deck crewmember or qualified ground personnel, of wing surfaces, leading
edges, engine inlets, and other critical surfaces of the aircraft that are in view
either from the flight deck or cabin (whichever provides maximum view). If
surfaces have not been treated with FPD (Freezing Point Depressant) fluid,
evidence of melting snow and possible freezing is sought. Also, evidence of any
ice formation that may have been induced by taxi operations is sought. If the
aircraft has been treated with FPD fluids, evidence of a glossy smooth and wet
surface is sought. If, as a result of these checks evidence of ice, snow, slush or
frost formations is observed, the aircraft should be returned for additional
deicing.
The crewmember should perform the pretakeoff contamination check from the
best vantage point available under the current conditions of the aircraft. There
is no best vantage point under all conditions.
The aircraft must be parked and not in motion for the entire time that the flight
deck crewmember is not at his or her station.
In some cases, it may become necessary to unseat passengers in the vicinity of
the overwing vantage point area to conduct the pretakeoff contamination check.
The flight deck crewmember making the check must ensure that all unseated
passengers are reseated with seatbelts fastened before returning to the flight
deck.
The exterior surface areas that may be viewed from inside the aircraft are deiced
or anti-iced first so that during the pretakeoff contamination check it can be
determined that other areas of the aircraft are clean since areas deiced or antiiced
first will generally freeze first.
In the darkness of night, the crewmember should use wing and other aircraft
illumination lights on the outside of the aircraft. All lighting inside the cabin
should be dimmed to improve the visibility through the cabin windows. The
crewmember may, where practical, call upon the assistance of qualified ground
personnel. If under any circumstance, the pilot in command cannot ascertain
that the aircraft is clean, takeoff should not be attempted.
The decision to takeoff, following pretakeoff contamination check remains
the responsibility of the pilot in command.
737
Flight Manual Continental
Sec. 3 Page 327
Rev. 11/15/02 #41
Anti-Icing Fluid Holdover Times
Holdover time is the estimated time an application of an anti-icing fluid will
prevent the adherence of frost, ice, snow, or slush on the treated surfaces of an
aircraft. Holdover time is obtained by anti-icing fluids remaining on the aircraft
surfaces. Holdover time begins when the final anti-icing application
commences, and expires when the anti-icing fluid applied to the aircraft wings,
control surfaces, engine inlets, and other critical surfaces loses its effectiveness.
Due to their properties, SAE Type I fluids form a thin liquid wetting film, which
provides limited holdover time, especially in conditions of freezing
precipitation.
SAE Type II and IV fluids contain a pseudoplastic thickening agent, which
enables the fluids to form a thicker liquid wetting film on external aircraft
surfaces. This film provides a longer holdover time, especially in conditions of
freezing precipitation.
The “Guidelines to Holdover Times” table gives an indication as to the time
frame of protection that could reasonably be expected under conditions of
precipitation. However, due to the many variables that can influence holdover,
these times should not be considered as minimums or maximums, as the actual
time of protection may be extended or reduced, depending upon the particular
conditions existing at the time.
Sec. 3 Page 328
Rev. 11/15/02 #41 Continental
737
Flight Manual
Holdover Times
The responsibility for the application of this data remains with the user.
Caution: This Table is for use in departure planning only, and should be
used in conjunction with pre-takeoff contamination check
procedures.
Caution: The time of protection will be shortened in heavy weather
conditions. Heavy precipitation rates or high moisture content,
high wind velocity and jet blast reduce holdover time below the
lowest time stated in the range. Holdover time may be reduced
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