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Thursday, September 1, 2005

Tool Crib

Be Cool with Big Ass Fans

Building 1244 at NASA's Langley Research Center is a large facility housing a docking simulator once used to teach astronauts of the Gemini Project how to dock the lunar module. Cutting-edge technology still happens on the floor of this building located in Hampton, Virginia, which is known for hot, humid summer days. Because air-conditioning was impractical for the 90,000 square foot facility with 100 foot ceilings, the facility coordinator went looking for a solution to help deal with the hot summer temperatures.

The Big Ass Fan's unique design creates large volumes of air to move off the fan blade and allows the fans to operate efficiently at lower speeds. These slow-moving fans generate a large column of air equal to the diameter of the fan. The air columns are pushed downward then hit the floor, and the air radiates outward until it hits a wall and is pushed back up to the ceiling. Over time that airflow gains momentum and creates a continuous breeze.

The fans use just five cents of electricity per hour with their one-horsepower motor. The variable speed controls preserve the life of the motor by reducing torque on start-up. Butch Lilly, senior facilities system engineer at Langley, said the fans were easy to install and added, "We had dead air." Once the fans were installed, he said, "Now there's an actual light breeze in the building and the breeze gets into all the corners." Big Ass Fans, 877-244-3267, www.bigassfans.com

DASSAULT DA50: The writer stated that the "...crew had power on the aircraft and noticed an electrical burning smell from the cabin. After investigating, they found the cabin indirect lighting circuit breaker popped. The maintenance facility troubleshot the problem to a power supply (P/N 18-941-1) that burned up." This report recommends further inquiry into this power supply to determine suitability for its continued use. "Dassault Aviation issued a `RECOMMENDED' Service Bulletin F50-335 for replacing the power supplies with an improved power supply that incorporates a protection circuit. This aircraft will have SB -335 installed as soon as parts can be procured."

CESSNA 550: While lowering the landing gear the pilot noticed the "anti-skid inop" light illuminated. Pilots made an uneventful landing, however, the emergency brake system had to be used to stop the airplane. Mechanics started troubleshooting procedures and discovered the power brake pump seized, causing the motor to trip the circuit breaker. The motor was tested on a bench and found to be working properly. At time of writing, the power brake pump and motor assembly have been sent out for repair/overhaul. Because Cessna does not have a TBO on either the motor or the pump, it is suggested that a TBO of 500 to 600 landings be applied to these components.

HONEYWELL TPE 331: The respondent stated that this destroyed engine's turbine bearing (P/N 3101092-1) has identification markings from the vendor that reworked and overhauled this part in 1995. "Rework and overhaul of this bearing is no longer approved by the manufacturer's current TBO program (SB 72-0180, R31) and requirements now call for replacement of this bearing at each hot-section inspection. Evidence leads to the belief that the bearing rollers turned in their cage, thus allowing the rotating group to move off center and contact the turbine housing--resulting in catastrophic failure."

RAYTHEON (BEECH) 1900D: "During an `I' check inspection, the upper and lower horizontal spar caps were found with corrosion in the area of the elevator hinges," stated the technician. "This area was not treated or primed by the factory during aircraft manufacture and thus was conducive to corrosion." The submitter recommended that: "1. Beechcraft (Raytheon Aircraft) add details of damage allowance to the structural repair manual, and 2. Recommend all areas of the airframe to be treated to prevent further corrosion."

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