.
Extending the landing gear early during the approach provides
additional cooling for tires and brakes.
.
In–flight cooling time can be determined from the “Brake Cooling
Schedule” in the Performance–Inflight section. During flight planning consider the following:
.
High temperatures inflict performance penalties which must be
taken into account on the ground before takeoff.
.
Alternate takeoff procedures (No Engine Bleed Takeoff, Improved
Climb Performance, etc.)
Moderate to Heavy Rain
Flights should be conducted to avoid thunderstorm or hail activity by overflight or circumnavigation. To the maximum extent possible, moderate to heavy rain should also be avoided.
If heavy rain is encountered:
ENGINE START switches ....................................................... CONT
Thrust Levers ............................................................... Adjust Slowly If thrust changes are necessary, move the thrust levers slowly. Avoid changing thrust lever direction until engines have stabilized at a selected setting.
Copyright . The Boeing Company. See title page for details.
Supplementary Procedures -Adverse Weather 737 Flight Crew Operations Manual
Turbulence
During flight in light to moderate turbulence, the autopilot and/or autothrottle may remain engaged unless performance is objectionable. Increased thrust lever activity can be expected when encountering wind, temperature changes and large pressure changes. Short–time airspeed excursions of 10 to 15 knots can be expected.
Passenger signs ...................................................................................ON Advise passengers to fasten seat belts prior to entering areas of reported or anticipated turbulence. Instruct flight attendants to check that all passengers' seat belts are fastened.
Severe Turbulence
Autothrottle........................................................................DISENGAGE
AUTOPILOT ................................................................................... CWS A/P status annunciators display CWS for pitch and roll.
Note: If sustained trimming occurs, disengage the autopilot.
ENGINE START switches ................................................................ FLT
Thrust ...................................................................................................Set Set thrust as needed for the phase of flight. Change thrust setting only if needed to modify an unacceptable speed trend.
Copyright . The Boeing Company. See title page for details.
Supplementary Procedures -Adverse Weather 737 Flight Crew Operations Manual
PHASE OF FLIGHT AIRSPEED
CLIMB 280 knots or .76 Mach
CRUISE Use FMC recommended thrust settings. If the FMC is inoperative, refer to the Unreliable Airspeed page in the Performance–Inflight section for approximate N1 settings that maintain near optimum penetration airspeed.
DESCENT .76 Mach/280/250 knots. If severe turbulence is encountered at altitudes below 15,000 feet and the airplane gross weight is less than the maximum landing weight, the airplane may be slowed to 250 knots in the clean configuration.
Note: If an approach must be made into an area of severe turbulence, delay flap extension as long as possible. The airplane can withstand higher gust loads in the clean configuration.
Copyright . The Boeing Company. See title page for details.
Supplementary Procedures -Adverse Weather 737 Flight Crew Operations Manual
Windshear
Windshear is a change of wind speed and/or direction over a short distance along the flight path. Indications of windshear are listed in the Windshear Escape Non-Normal maneuver in this manual.
Avoidance
The flight crew should search for any clues to the presence of windshear along the intended flight path. Presence of windshear may be indicated by:
.
Thunderstorm activity
.
Virga (rain that evaporates before reaching the ground)
.
Pilot reports
.
Low level windshear alerting system (LLWAS) warnings. Stay clear of thunderstorm cells and heavy precipitation and areas of
known windshear. If the presence of windshear is confirmed, delay takeoff or do not continue an approach.
Precautions
If windshear is suspected, be especially alert to any of the danger signals and be prepared for the possibility of an inadvertent encounter. The following precautionary actions are recommended if windshear is suspected:
Takeoff
.
Use maximum takeoff thrust instead of reduced thrust
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