What are the CRITICAL SURFACES AND RISKS


1 Wing: Performance Loss


A contaminated wing can increase both drag and the stall speed by unknown amounts. This means the length of your takeoff roll may increase. At rotation speed, the aircraft may not be ready to fly. Your normal climb rate might exceed the contaminated wing stall angle, possibly without triggering the stall warning device. If you get out of ground effect, your rate of


climb may also decrease.


2 Wing: Control Degradation Contamination can lead to altered flight characteristics, and asymmetric contamination can lead to asymmetric lift, which can cause a roll upset.


3 Wing: Aileron Gap Contaminants can slide into the gap and restrict aileron movement.


4 Jet Engine Contaminants can break away during takeoff, and be ingested into the engine(s). This can cause the engine to flameout, or damage the fan and/or compressor blades, which could subsequently cause


the engine to fail.


5 Horizontal Stabilizer, Elevator Gap Contamination on the topside of the tail can lead to a slight drag increase. Also, contaminants can slide into the gap and restrict elevator movement.


6 Horizontal Stabilizer: Control Degradation


Contamination, particularly a spanwise ridge, near the leading edge on the lower surface of the tail, may cause a pitch upset.


7 Instruments and Sensors Contaminants forming on or blocking pitot tubes, static ports, angle-of-attack vanes, or engine probes may give false airspeed, attitude, angle of attack or engine power indications. If you suspect your airspeed indicator and/or AOA instruments are giving you incorrect readings, reject the takeoff. If it is too late to reject


takeoff, fly pitch attitude and power. Do not rely on suspicious instrumentation.


8 Fuselage A big concern is the drag increase. The weight of contamination is insignificant compared to the maximum takeoff weight of the aircraft. For example, coating the top surfaces of a light twin with one half-inch of ice adds about 40 pounds (18 Kg). This is negligible compared to the lift and drag penalties. Also, for aircraft with aft-mounted engines, contamination may break off the fuselage and impact or be ingested by an aft-mounted


engine. 5 Surface Contamination


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