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led the pilot to further investigate, preventing a possible control surface jam in flight. Pay specific attention to areas prone to corrosion: external skin areas, wheel wells, landing gear, wing flaps, spoiler recesses, battery compartments, and areas near lavatories and galleys. Related to corrosion is atmospheric degradation of polymers, such as those used in aircraft hoses and seals. Those will be evident by stiffness and cracking of the rubber and, left unchecked, as leaks.
Chafing is another cause of failure that, in many cases, can be detected early. Last year, an aircraft at my home field had to land on its nose due to a nose gear malfunction. A prop strike ensued. The culprit was an improperly long screw installed on a gear door, which jammed a compo- nent of the nose wheel. Long scratches on that component indicated that the interference existed over several flights. Chafing will show as scratches or wear on moving compo- nents such as landing gear and flaps. Chafing may also be a result of components that contact each other due to aircraft vibrations. Figure 6 shows a broken aspirator high-pressure tube that a pilot found while inspecting the environmental control system in his Citation. Flying with the line broken would have resulted in pressurization issues.
If the engine cowl or inspection covers to the APU, ECS, etc., can be opened easily, it is a good idea to open those as part of a thorough preflight inspection. Look for leaks and loose components. In a turbine engine, inspect the bleed lines for looseness and cracks. In a reciprocating engine,
Figure 6
pay particular attention to the exhaust system and the turbochargers (if equipped), as those are subject to high temperature and stress. Exhaust leaks will show as white streaks near joints or cracks in the system.
Preflight an Aircraft Post-Maintenance
The other week I was at the shop and observed a customer arriving to pick up their high-performance turbine aircraft after an annual maintenance event. The pilot loaded up
12 • TWIN & TURBINE / July 2022
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