FAA Supplemental Type Certificate Overview

Supplemental Type Certificate (STC)

• An STC outlines methods and techniques for aircraft return to service without additional engineering or flight testing.
• A list of approved STCs can be found on the FAA website under the Summary of Supplemental Type Certificates
• After obtaining an STC, follow instructions precisely and document all changes on FAA Form 337.
• Prior to returning an aircraft to service, ensure all STC conditions are met through inspection by an FAA Inspector, IA-holding technician, certified repair station, or another approved entity.
• Keep installation and maintenance instructions for each STC with the aircraft records.

FAA Forms and Records

• Commonly used FAA forms for maintenance include:
  • FAA 337 - Major repair & Alteration (Airframe, Powerplant, Propeller or Appliance)
  • 8130-3 - Authorized Release Certificate
  • 8130-6 - Application for Airworthiness Certificate
  • 8610-1 - Mechanic's Application for Inspection Authorization
  • 8120-11 - Suspected Unapproved Parts Report
  • 8710-1 - Airman Certificate and/or Rating Application

Maintenance Release

• A person authorized by the national airworthiness authority signs a maintenance release, certifying maintenance compliance with applicable requirements.
• For certified aircraft, this may be an Aircraft Maintenance Engineer or Technician.
• For amateur-built aircraft, the owner or builder may sign the release.
• A maintenance release can be known as a certificate of release to service (CRS).

Maintenance Record Entries

• Federal Aviation Regulations mandate a permanent maintenance record for aircraft, with entries made for each completed inspection.
• The maintenance program for commercially operated aircraft is detailed in the operator's approved specifications (Op Specs).
• Airlines use a continuous maintenance program with routine and detailed inspections.
• "Checks" (A-check, B-check, C-check, and D-checks) involve increasing levels of detail.
  • A-checks are least comprehensive and occur frequently.
  • D-checks are highly comprehensive, involving disassembly, overhaul, and system/component inspection. They occur less frequently, typically three to six times throughout an aircraft's service life.

Non-routine Inspection

• A non-routine inspection is required following component failures or incidents that could potentially damage an engine.
• Triggering events include:
  • Ingestion of birds, ice, or foreign objects.
  • Temperature or RPM over limit incidents.
• Even if immediate engine performance issues are not evident, an inspection is vital.
• Delayed inspection of foreign object damage, for instance, can result in blade failure, causing further damage or engine destruction.

Methods of Inspection

• Engine part inspection during maintenance/overhaul is categorized into three types:
  • Visual
  • Dimensional
  • Structural NDT (Non-destructive Testing)

Visual Inspection

• Visual inspection is often sufficient for detecting many defects on engine components, allowing for an airworthiness determination.

Magnetic Particle Inspection

• Magnetic particle inspection uses a magnetic field and ferromagnetic particles to detect surface and subsurface discontinuities in ferrous materials.
• The inspection process involves magnetizing the part and applying a magnetic powder.
• Discontinuities disrupt the magnetic field, causing particles to accumulate, creating an indication of the defect.
• This method is effective for identifying cracks, seams, porosity, and other flaws.

Magnaglo Inspection

• Magnaglo inspection involves using a fluorescent particle solution under black light, enhancing visibility and detection of smaller flaws.
• This method is particularly suitable for gears, threaded parts, and aircraft engine components.

Liquid Penetrant Inspection

• Penetrant inspection is a nondestructive testing method used to detect surface defects in nonporous materials like aluminum, magnesium, brass, copper, cast iron, stainless steel, titanium, ceramics, plastics, rubber, and glass.
• It can detect cracks, porosity, and lack of bond between joined metals.
• Since penetrant inspection relies on the penetrant entering open surface defects, magnetic particle inspection is generally preferred for magnetic materials.
• Penetrant inspection involves applying a penetrating liquid that enters surface openings, becoming visible after processing.
• The inspection is enhanced by using visible or fluorescent dyes.

Dye Penetrant Inspection

• Dye penetrant inspection serves the same purpose as fluorescent penetrant inspection, but without requiring specialized UV light equipment.
• It uses a penetrating liquid that is clearly visible to the inspector.

Fluorescent Penetrant Inspection

• Fluorescent penetrant inspection utilizes a black light (UV lamp) to illuminate the fluorescent dye making defects more visible.
• The process includes:
  • Thorough surface cleaning.
  • Penetrant application.
  • Penetrant removal with cleaner or emulsifier.
  • Part drying.
  • Developer application.
  • Inspection and interpretation of results.

This quiz covers the key aspects of Supplemental Type Certificates (STC) related to aircraft return to service without additional flight testing. You will learn about the necessary FAA forms, documentation procedures, and the roles of various approved entities in ensuring compliance with STC conditions. Test your knowledge on FAA regulations and procedures regarding aircraft maintenance.