AFS7

Inspection

• An inspection is a visual or physical verification that a task/component conforms to a prescribed standard.
• Inspections reduce the likelihood of errors that could affect airworthiness.
• Inspections include activities conducted during or after a task to review the work carried out by a tradesperson.

Hydraulic System Maintenance

• Leakage from any stationary connection is not permitted and must be rectified.
• A small amount of fluid seepage may be permitted on actuator piston rods and rotating shafts.
• Internal leakage beyond allowable limits must be rectified according to the relevant publication.

Leak Classification

• A stain does not wet an area around the leak source of more than ¾ of an inch in diameter within a 30-minute period.
• A seep won’t wet an area of more than 1.5 inches in diameter within a 30-minute period.
• A heavy seep fuel leak soon reappears after being wiped away and will spread over an area of up to 4 inches within 30 minutes of being wiped.
• A running leak quickly reappears after being wiped away and quickly spreads onto surrounding surfaces.

Locating External Point of Leak

• Loose fasteners such as rivets, screws, or bolts are the most common source of fuel leaks in integral tanks.
• Fuel can channel between attaching structural members and tank sealant.
• Start examinations from the point where the leak appears externally, usually at the lowest point of the wing or nearby fuselage.

Fuel Leak Disclosing Agents

• Fuel leak disclosing agents such as Semco 419 can be used to highlight the presence of fuel.
• Dust the area with Semco 419 immediately after drying the surface.
• Continue dusting while working toward the external point of fuel leak.

Welded Fuel Tanks

• Leaks in welded tanks can be caused by cracking or damage.
• These tanks must be drained and removed from the aircraft, and the leak repaired by welding.
• The tank must be thoroughly purged of all explosive fumes by steaming before welding.

Bladder Tanks

• Damaged bladder tanks are removed from the aircraft and repaired using an approved repair kit.
• All bladder tanks have a finite life and will eventually develop leaks.
• A leaking bladder tank is removed from the aircraft and replaced with a new or reconditioned tank.

Abrasive Wear and Other Gear Damages

• Abrasive wear includes scratching and scoring, dependent on the size of particles carried in the lubricant.
• Scoring is the heavy gouging of metal from the tooth surface as the temperature rises and the lubricant thins out.
• Pitting and spalling are associated with thin oil films and high temperatures.
• Cracking and breakage can be caused by faulty heat treatment or improper machining during manufacture.

Spring Inspection, Testing, and Adjusting

• Inspection and testing of springs are carried out according to the Maintenance Manual applicable to the major assembly the spring is part of.

Quiz on inspection procedures in aviation maintenance, including visual and physical verification, error reduction, and hydraulic system maintenance.