Aircraft Engineering Practice - Discipline Requirements
This domain tests aircraft engineering practice under Hong Kong's regulatory framework: how you classify work, select the approval route, release aircraft to service, and account for your signature. The exam favours applied judgement over recall.
Regulatory architecture
Hong Kong aircraft engineering is governed by the Civil Aviation Ordinance (Cap. 448) and CAD-issued HKARs. HKAR-21 covers design, production and changes; HKAR-145 approved maintenance organisations; HKAR-66 certifying staff; HKAR-147 training; and HKAR-M continuing airworthiness. ICAO Annex 8 is the international baseline, but the HKAR is the enforceable local requirement.
Airworthiness and release
A valid Certificate of Airworthiness depends on compliance with the approved type design, the approved maintenance programme, and Airworthiness Directives (ADs). ADs are mandatory; Service Bulletins are not, unless an AD or the approved programme makes them so. Maintenance must be released by a Certificate of Release to Service (CRS) issued by authorised certifying staff. Physical completion without a CRS is not release to service.
Changes and repairs
Classify first. A major modification or repair changes the type design or appreciably affects airworthiness - structure, performance, systems, or flight characteristics. It needs approved design data: an STC, major change approval, or CAD acceptance. A minor change may be approved under an approved design organisation's procedures. Design approval is separate from approval to embody: the installer needs the correct HKAR-145 scope and approved data.
Worked example
A Hong Kong-registered aircraft is offered a satcom installation that increases electrical load and alters the flight deck. It changes type design and affects electrical load and crew workload, so classify it as major. Route: obtain approved design data (STC or CAD major change approval); verify structural and electrical substantiation; embody under an HKAR-145 organisation with the right scope; update the AFM supplement, W&B, MEL and maintenance programme; conduct ground/flight tests; issue the CRS; and have CAD amend the C of A if required. Treating it as minor and issuing an internal engineering order is a mark-losing error.
Traps that cost marks
Common traps: treating all Service Bulletins as mandatory; using an HKAR-145 approval as if it were a design approval; assuming FAA or EASA approval is automatically valid in Hong Kong; issuing a CRS without approved data and inspection; and ignoring operational interfaces such as MEL, AFM, mass and balance, and crew training. Sign only for work you have verified; the HKIE Code of Conduct and CAD both attach accountability to the signature.