Specifications

SECTION IV
OPERATING INFORMATION
MODEL 560
ADVERSE FIELD CONDITIONS
All flight manual field length data assumes a dry, hard surface runway except where otherwise noted.
Precipitation-covered runway conditions will degrade braking effectiveness and will require significantly
greater actual takeoff and landing field lengths.
Considerations for landing on a precipitation-covered runway are similar to those for short field
operations where speed is minimized and maximum roll out distance is made available. Runway
composition, condition and construction, the amount of precipitation and the depth of main landing gear tire
tread remaining affect the magnitude of braking degradation, so it is impossible to apply a fixed factor to
cover all conditions. Again, maximizing rollout runway available and touching down at minimum safe speed
will provide the greatest possible margin.
Use of the thrust reversers on precipitation-covered runways is the same as that for a landing on a
normal or dry runway. Cockpit visibility is not hampered by blowing rain, snow, or ice thrown forward by the
thrust reversers except at low speed with idle reverse. Single-engine reversing during crosswind landings
on precipitation-covered runways should be used with discretion.
Precipitation covered and icy runways present particular hazards which must be understood in order to
achieve effective braking. Under normal braking conditions the antiskid system is very effective in
preventing skids and in producing minimum stopping distances, with the pilot applying and maintaining
steady maximum pressure. However, on a precipitation or ice covered runway, the phenomenon of
dynamic hydroplaning may greatly reduce the antiskid effectiveness, because the wheels either do not spin
up equally or do not spin up to the antiskid threshold speed. With 130 psi tires, hydroplaning may occur
above approximately 80 knots ground speed. It is important to maintain properly inflated tires with good
tread depth, and because ground speed is critical, to avoid tailwinds when operating in these conditions.
When braking on precipitation covered runways ensure that the wheels are down and tracking prior to
applying brakes. This will give the wheels time to spin up. Ensure that maximum weight is on the wheels,
i.e., deploy speed brakes. If runway permits, utilize maximum aerodynamic braking and thrust reversers to
slow the airplane prior to braking.
When braking is commenced, apply and maintain steady maximum pressure to the brake pedals.
Longer or more frequent antiskid pressure dumps may be experianced due to the precipitation-covered
surface, but this technique will produce the best overall stopping performance. Initial deceleration rate may
appear tobe weak, but will improve noticeably as the airplane groundspeed reduces.
After landing on ice or slush, a complete check of the airplane, including overboard vents and control
surfaces, should be conducted.
I 4-20 Configuration AA 56OMB-01