Issue Number 273 |
May
2002
|
|||||||
P.O. Box 189, Moffett Field, CA 94035-0189 |
||||||||
|
||||||||
All pilots are taught to be wary of wake turbulence, the "horizontal tornadoes" that trail behind the wingtips of any aircraft in flight, especially larger and heavier aircraft. The greatest hazard from wake turbulence is induced roll and yaw, particularly during the takeoff and landing phases where there is little altitude for recovery. A Captain's recent report to ASRS offers a graphic example of wake turbulence hazard:
The Aeronautical Information Manual (Chapter 7, Section 3) and Order 7110.65N, Air Traffic Control (Paragraphs 2-1-19 and 2-1-20) explain the respective pilot and controller responsibilities for wake turbulence avoidance. ATC is responsible in both VFR and IFR conditions for issuing wake turbulence advisories. An airport's air traffic controllers will provide an advisory to any VFR aircraft on its frequency that may, in the controller's opinion, be adversely affected by wake turbulence from a larger aircraft. This advisory will give the position, altitude (if known) and direction of flight of the larger aircraft, followed by the phrase, "Caution - Wake Turbulence." However, if a pilot accepts a visual approach clearance to follow an aircraft, the pilot accepts responsibility for separation and wake turbulence avoidance. Because wake turbulence is unpredictable, the controller is not responsible for predicting its existence or effect. When any doubt exists about maintaining safe separation distances between aircraft during approaches, pilots should ask the Tower controller for updates on separation distance and aircraft ground speed. Respect Rotary Wing Wake Helicopter wakes may be of significantly greater strength than those from a fixed wing aircraft of the same weight. The strongest wake can occur when the helicopter is operating at lower speeds (20-50 knots), as discovered by this General Aviation fixed wing pilot:
This event was classified as an incident rather than an accident. Rotor vortices circulate outward, upward, around, and away from the main rotor(s) in all directions. Pilots of small aircraft should operate three or more rotor diameters away from any helicopter in a slow hover taxi, or stationary hover. |
||
A Cessna pilot influenced by "get-home-itis" ignored obvious signs during a run-up and takeoff that all was not right with the prop control.
Procedures not recommended: Use of force on a cockpit control, and ignoring a low RPM setting during takeoff.
A General Aviation pilot landed at an airport in the early evening to refuel his airplane on a cross-country flight. All proceeded normally until it was time to restart the engine.
Most hand-propping accidents occur either because an airplane is left unattended, or because an unqualified person is at the controls. Pilots who undertake this procedure should always assume that the propeller is "hot" (will start of its own volition) and have a qualified, fully briefed person at the controls. The FAA also recommends that prior to start-up, the aircraft rotating beacon or strobe should be turned on to alert persons nearby that the propeller will be set in motion. |
|||
An air carrier Captain recently filed this report with ASRS describing "electronic sensory saturation during a critical phase of flight."
|
||
|
|
||||||||||||||||||||