MODULE 7 · SYLLABUS 7.19 · LEVEL 2

Chapter 19: Abnormal Events

Event reporting and special inspections after lightning, HIRF, heavy landing, turbulence and other abnormal loads.

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B1 syllabus coverage

Supplied B1 Module 07A textbook: PDF pages 493–500.

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🎯 What you'll learn
  • Event information and aircraft status
  • Lightning damage assessment
  • HIRF and electrical-system effects
  • Heavy landing and overload paths
  • Turbulence and flight-load events
  • Other events and controlled release
📖 The lesson

Supplied B1 Module 07A textbook: PDF pages 493–500.

Abnormal Events EVENT Crew + recorded data → INSPECT Approved scope → ASSESS Damage + systems → RELEASE Evidence + records Visible marks may not represent the complete damage
Conceptual illustration. Use the applicable maintenance data for actual limits.

Event information and aircraft status

A special inspection responds to conditions outside normal operation. Record crew reports, parameters, event timing and affected systems; do not reduce a detailed report to a vague 'hard landing'. Establish the aircraft's maintenance status and use the manufacturer's event procedure. Some inspections are triggered by recorded loads or operational criteria even if damage is not immediately visible. Where instructions do not cover the event, obtain the required technical direction. A normal postflight walk-around is not automatically a complete abnormal-event inspection.

Recall check

What determines a special-inspection requirement? The event information and applicable manufacturer procedure.

Lightning damage assessment

A strike can cause local thermal damage and indirect electrical effects. Inspect likely attachment and exit areas, adjacent structure, bonding and lightning-protection features as directed. Metal may show pitting or burns; composite protection and underlying laminates can be affected. Check required systems and recorded faults, not just static wicks. Lightning and static electricity protection are related but distinct: static wicks are not the sole path for a lightning strike. Apply the aircraft's zones and inspection criteria to define coverage.

Recall check

Why inspect beyond visible lightning marks? Hidden structural and indirect system damage may exist.

HIRF and electrical-system effects

High-intensity radiated fields can disturb electronic systems without the local burns associated with a direct strike. Use event reports, BITE records and required functional checks to assess possible effects. Inspect shielding, bonding and installation integrity where the procedure calls for them. Interference symptoms may be intermittent and can involve several systems. Do not invent a universal HIRF inspection from a generic description. The applicable maintenance instructions define which tests and dispositions are needed before release.

Recall check

What may HIRF exposure affect? Electronic operation and electromagnetic compatibility.

Heavy landing and overload paths

Landing loads pass through tyres, wheels, gear, attachments and surrounding structure. The required inspection can extend to wings, fuselage, engines and other installations depending on the aircraft and event. Check deformation, leakage, cracks, alignment and the specified measurements. A sound-looking tyre does not prove that hidden attachments are undamaged. Use event thresholds and staged inspection requirements rather than deciding from passenger discomfort alone. Record the inspection scope and results so the release decision rests on evidence.

Recall check

Why can heavy-landing inspection extend beyond the landing gear? Loads are transmitted into connected aircraft structure.

Turbulence and flight-load events

Severe turbulence, overspeed or excessive manoeuvre loads may affect lifting surfaces, attachments and installed equipment. Use the crew report and recorded data where available to identify the event and required inspection. Check the relevant control surfaces, hinges, structure and systems using the prescribed method. Some damage may be internal or evident only from dimensional checks. Normal appearance after landing does not eliminate an inspection triggered by a documented limit exceedance. Coordinate technical assessment with operations and maintenance control.

Recall check

What is useful when assessing a flight-load event? Crew reports and relevant recorded parameters.

Other events and controlled release

Bird strikes, tail strikes, engine ingestion, fire, fluid spills and ground collisions each need appropriate event-specific assessment. Secure the aircraft, preserve useful evidence and use approved instructions for the affected systems and structure. Complete repair, follow-up inspections and tests, then document the work. Do not release the aircraft merely because the reported symptom has stopped. The authorised release process must consider the whole required inspection scope and any remaining limitations or deferred items.

Recall check

What is required for release after an abnormal event? Completion and recording of the required assessment, correction and checks.

Apply the knowledge

Work through these examples before starting the quiz. Explain why the other choices would not meet the requirement.

A lightning strike leaves one visible mark. What is appropriate?

Follow the full specified strike inspection scope — Visible marks may not represent all structural or system effects.

Crew report severe turbulence but no exterior damage is obvious. What should happen?

Apply the event criteria and required inspection procedure — Documented load events can require inspections without visible damage.

A heavy-landing inspection finds gear attachment deformation. What is correct?

Obtain the applicable repair or disposition before release — Attachment deformation requires structural assessment.

An intermittent system fault follows suspected HIRF exposure. What evidence is useful?

Fault records and prescribed system tests — HIRF can affect electronics without direct thermal marks.

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