It began as an occasional single drop of fuel from a brass fuel shutoff valve at the lowest point of the fuel system on a weight-shift-control experimental light-sport aircraft. It was rarely noticed, and never apparent when operating from sod airstrips. The owner considered it to be little more than an inconvenience for months, until it was parked for a time on a concrete tarmac for breakfast at a local airport restaurant. Read more

 
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Engines
Q. What are the common sources of fuel contamination?

A. Clean fuel is imperative for the safe operation of an aircraft. Of the accidents attributed to powerplant failure from fuel contamination, most have been traced to:

• failure to remove contamination from the fuel system during preflight
• servicing aircraft with improperly filtered fuel from small tanks or drums
• storing aircraft with partially filled fuel tanks
• lack of proper maintenance.

Rust is common in metal fuel containers and is a common fuel contaminant. Metal fuel tanks should be filled after each flight, or at least after the last flight of the day to prevent moisture condensation within the tank. Another way to prevent fuel contamination is to avoid refueling from cans and drums. Use a water-filtering funnel or a funnel with a chamois skin when refueling from cans or drums. However, the use of a chamois will not always ensure decontaminated fuel. Worn-out chamois will not filter water; neither will a new, clean chamois that is already water-wet or damp. Most imitation chamois skins will not filter water.

Powered Parachute
Q. Where can I fly my powered parachute?

A. The powered parachute can be transported by trailer from one flying field to the next. For as many benefits as this provides, transporting the powered parachute into unfamiliar territory also includes some safety and operational issues.

Make contact with the airport management to inquire about any special arrangements that may need to be made prior to departing from an unfamiliar airport. Check the Airport/Facility Directory (A/FD) for traffic pattern information, no-fly zones surrounding the airport, and special accommodations that may need to be arranged.

While in the vicinity of an airport within Class G airspace, FAR 91.126 states that powered parachutes must avoid the flow of fixed wing aircraft. In addition, you should inform local pilots about some of the incidentals of powered parachute flight (such as flying low and slow); the more information that other category pilots know about powered parachute flight characteristics, the more they will understand the specific needs of the powered parachute in flight. Sharing the same airspace with various aircraft categories requires pilots to know and understand the rules, and understand the flight characteristics and performance limitations of the different aircraft.

Weight Shift Trike
Q. What are the battens?

A. Stiff preformed battens are parts of the wing that create and maintain the airfoil shape from the root to the tips of the wing. They serve a similar purpose and are like a rib in a fixed wing airplane. Battens are removable so the wing can be taken apart for storage or transporting. Additionally, a foam or Mylar stiffener is inserted in a pocket at the leading edge to keep a rigid airfoil shape between the battens from the leading edge up to the airfoil high point. Double surface wings have additional ribs on the bottom surface that are straight or formed to maintain the bottom surface camber.

Fixed-Wing Airplane
Q. What is an effective visual scanning technique?

A. Effective scanning is accomplished with a series of short, regularly spaced eye movements that bring successive areas of the sky into the central visual field. Each movement should not exceed 10 degrees, and each should be observed for at least one second to enable detection. Although back-and-forth eye movements seem preferred by most pilots, each pilot should develop a scanning pattern that is most comfortable and then adhere to it to ensure optimum scanning. Even if entitled to the right-of-way, a pilot should yield if another aircraft seems too close.

Rotorcraft
Q. What is a slip in the helicopter?

A. A slip occurs when the helicopter slides sideways toward the center of the turn. It is caused by an insufficient amount of antitorque pedal in the direction of the turn, or too much in the direction opposite the turn, in relation to the amount of power used. In other words, if you hold improper antitorque pedal pressure, which keeps the nose from following the turn, the helicopter slips sideways toward the center of the turn.

Dennis Souder of Kolb Aircraft explains how the Kolb Firefly ultralight evolved from the earlier Kolb Firstar model. The Firefly has a reduced wing area but employs wing flaps specifically to comply with the requirements of ultralight advisory circular AC 103.7. The design goal was to produce an FAR103 legal ultralight that could be powered with the popular Rotax 447 twin-cylinder engine. Read the article.