7.19 Abnormal Events Flashcards
Where does most lightning occur?
Most lightning occurs in the tropics.
At what altitudes is lightning most likely to hit an aircraft?
Lightning is most likely to hit an aircraft at altitudes of 8000 ft to 14,000 ft.
What causes lightning strikes on aircraft?
Lightning strikes are often caused by the aircraft flying through areas where large charges have built up, such as within clouds or in areas of precipitation.
What types of damage can lightning strikes cause to aircraft?
Lightning strikes can cause direct damage to metallic and non-metallic structures and indirect damage to electrical/electronic systems.
What is direct damage from lightning strikes?
Direct damage is defined as metallic structures burned, melted, or distorted, and non-metallic structures burned, punctured, or delaminated.
What is indirect damage from lightning strikes?
Indirect damage is identified as damage to electrical/electronic systems, wires, shielding, and shield terminations caused by large electrical transients.
What are common areas where lightning strike damage occurs?
Common areas include the nose section, engine nacelles, wing tips, horizontal stabiliser tips, and vertical fin tip.
What should flight crews do after a lightning strike?
Flight crews must report all lightning strikes via the tech log to ensure an inspection can be carried out.
What should be inspected if a lightning strike area is known?
A careful inspection is required to assess the type and quantity of damage that has occurred.
What are signs of direct damage on a metal structure?
Signs include small circular melt marks or pitting, burned or discoloured paint, and damaged fasteners.
What is the purpose of lightning strike diverter strips?
Diverter strips are bonded to the airframe to protect composite structures from catastrophic damage caused by lightning strikes.
What is the procedure for inspecting an aircraft for direct damage?
Examine external and internal areas for damage, check metallic structures for holes or pits, and inspect the radome and composite components.
What can high-intensity lightning strikes cause?
They can cause problems to electrical/electronic equipment due to induced voltages.
What should be checked for indirect damage after a lightning strike?
Inspect external lights, standby magnetic compass, fuel quantity system, fly-by-wire systems, and all radio/navigation systems.
What happens to ferrous components after a lightning strike?
They can become magnetised, affecting magnetic instruments like compasses.
What is the function of static dischargers?
Static dischargers dissipate static charge that builds up on the aircraft to prevent interference with radio receivers.
What are High Intensity Radiated Fields (HIRF)?
HIRF are electromagnetic radiation that can potentially affect an aircraft’s electrical and electronic systems.
What can cause HIRF in aircraft?
HIRF can be caused by external sources like radio transmitters, internal transmitters, and high power circuits switching on or off.
What is essential for maintaining electromagnetic protection in aircraft?
A thorough visual inspection is crucial to identify and rectify any degradation of electromagnetic protection.
What checks are required after a pilot reports HIRF effects?
Functionally test all systems and inspect the electrical bonding system, static dischargers, and built-in shielding.
What factors affect structural stresses during landing?
The structural stresses encountered during landing depend on the aircraft’s gross weight and the severity of the landing impact.
What is a special inspection required for?
A special inspection must be performed if the flight crew reports a heavy or rough landing.
What is the Maximum Design Landing Weight (MDLW)?
MDLW is the maximum weight at which an aircraft is designed to land safely.
What is a common sign of a heavy landing?
A wrinkled or creased wing skin is the most easily detected sign of a heavy landing.
What are potential areas of damage after a heavy landing?
Potential areas of damage include spar webs, bulkheads, nacelle skin, firewall skin, wing, and fuselage stringers.
What is a Phase I inspection?
A Phase I inspection is applicable after a hard landing or high drag/side-load landing to determine if further inspections are necessary.
What does a Phase I inspection focus on?
Phase I inspection focuses on vulnerable areas, especially those prone to damage during hard landings.
What areas are commonly checked during a Phase I inspection?
Common areas include Main Landing Gear (MLG) struts and various structural components for signs of damage.
What happens if damage is detected during Phase I inspection?
If damage is detected, a Phase II inspection is necessary.
What defines an overweight landing?
An overweight landing is defined as landing at a gross weight exceeding the maximum design landing weight.
What inspections are required after an overweight landing?
Common areas checked include wrinkled wing skin, fuel leakage, and various structural components for damage.
What is the purpose of inspecting after severe turbulence?
The inspection focuses on checking for structural damage due to excessive loads on the wings.
What should be inspected after fire damage?
Any visible or non-visible damage requires repair or replacement, as structural integrity may be compromised.
What is required for parts that were totally submerged in flood water?
They must be completely disassembled, cleaned, dried, and treated with a corrosion inhibitor.
