Why is the commercial chain the heaviest? Because commercial air transport is the case where a member of the public pays a stranger's organisation and entrusts it with their life, sight unseen. The passenger cannot inspect the training records or the maintenance release; the regulation inspects them instead, and every duty in this lesson exists so that the trust a ticket represents is earned by a system rather than by luck. That is the sense in which CAT flights must meet the applicable operational requirements: compliance is the product being sold.
What counts as commercial air transport
A commercial air transport operation is an aircraft operation to transport passengers, cargo or mail for remuneration or other valuable consideration, a definition the Air Law course located in Article 2 of the regulation. Money changing hands is the trigger, and that is exactly where the exam digs, because Article 6 carves out flights that look paid-for yet may be flown under the light Part-NCO regime instead:
Cost-shared flights — by private individuals, on the condition that the direct cost is shared by all the occupants, pilot included, and no more than six persons share it. Direct cost means what the flight itself costs, fuel, airfield charges and aircraft rental, with no element of profit.
Competition flights and flying displays — provided the payment is limited to recovery of direct costs plus a proportionate contribution to annual costs, and prizes stay under a value set by the competent authority.
Introductory flights, parachute dropping, sailplane towing and aerobatic flights — performed by a training organisation or by a non-profit body created to promote aerial sport or leisure aviation, provided the organisation owns or dry-leases the aircraft, distributes no profit outside itself, and keeps flights involving non-members a marginal activity: a very minor part of what it does, flown to promote itself or attract members, never a regular income line.
A separate derogation covers flights that carry no passengers or cargo while an aeroplane is ferried for refurbishment, repair, inspection, delivery or export, together with type-development flights by design and production organisations: provided the aircraft is not listed on an AOC or a declaration, these run under the national law of the state where the operator has its principal place of business. Notice what the carve-outs have in common: either nobody is buying transport, or the money is capped at cost. The moment profit enters, the operation is CAT and the whole commercial chain applies.
The management system
Part-ORO's central demand is that safety be run as a management system, not as good intentions. This is the safety management system the previous lesson met in Annex 6, under the shorter name the EU rules give it. The operator shall establish, implement and maintain a system that includes:
Lines of responsibility — clearly defined throughout the operator, including a direct safety accountability of the accountable manager, the person who answers for safety with the authority.
A safety policy — the description of the operator's overall philosophies and principles with regard to safety.
Hazard identification and risk management — identifying the aviation safety hazards the operator's activities entail, evaluating them, managing the associated risks, and verifying that the mitigating actions work.
Trained and competent personnel — maintained so, as a system obligation rather than a hiring hope.
Documentation of key processes — including the process for making personnel aware of their responsibilities and the procedure for amending the documentation itself.
Compliance monitoring — a function that checks the operator against the requirements and feeds findings back to the accountable manager, so corrective action actually happens.
One qualifier keeps the system honest at both ends of the industry: it shall correspond to the size of the operator and the nature and complexity of its activities. A two-aeroplane island carrier and a global network airline both need all six elements; what scales is the machinery, not the obligation.
Accident prevention and the flight safety programme
Inside the management system, the safety-risk element is the operator's accident-prevention and flight-safety programme, and the rules spell out its working parts. Hazards are found by reactive and proactive schemes that formally collect, record, analyse, act on and feed back what is learned. Reporting systems, confidential ones included, must close the loop back to the reporter. Risks found are put through a formal process: analysed for likelihood and severity, assessed for tolerability, and controlled down to an acceptable level, with the management levels who may accept a risk named in advance.
The programme then watches itself. Internal safety investigations extend beyond the occurrences that must be reported to the authority; safety performance is monitored through reporting, studies, reviews, audits and surveys; change is managed as its own documented process, since new routes, fleets and procedures import new hazards; and the whole system aims at continuous improvement. The flight data analysis programme of the previous lesson plugs straight into this machinery: its trend findings are exactly the proactive hazard feed the schemes exist to consume.
Crew, cabin and conduct
A cluster of Part-CAT rules governs people, and each is a favourite one-liner in the exam. The operator shall ensure that all crew members can communicate with each other in a common language, and that all personnel can understand the language of the operations-manual parts that concern their duties, written in a form that observes human-factors principles.
No person may be in any part of an aircraft in flight that is not designed for the accommodation of persons, with one gatekeeper for the exceptions: the commander may grant temporary access for action necessary for the safety of the aircraft or of any person, animal or goods, or to a cargo part designed to be accessible in flight.
For portable electronic devices, the operator shall not permit the use of any PED that could adversely affect the performance of the aircraft's systems and equipment, and shall take all reasonable measures to prevent such use. The operator decides which devices may be used in which phase; the commander may, for any reason and during any phase of flight, require devices to be deactivated and stowed.
For psychoactive substances the rule has four layers:
The door — the operator takes all reasonable measures to ensure no person enters or is in an aircraft under an influence likely to endanger the aircraft or its occupants; that covers passengers at the boarding door as much as crew.
A policy — prevention and detection of misuse, covering flight and cabin crew and other safety-sensitive personnel under the operator's direct control.
A testing procedure — objective, transparent and non-discriminatory.
Reporting — a confirmed positive test is not an internal matter: the operator informs its competent authority and the authority responsible for the person, such as the medical assessor of the licensing authority.
The endangerment rule closes the cluster with the widest net: no person may recklessly, intentionally or negligently act, or fail to act, so as to endanger an aircraft or a person in it, or cause an aircraft to endanger any person or property. The omission half matters: not securing a lock, not reporting a defect, not speaking up can each qualify. The same rule is where Europe placed the post-Germanwings requirement that flight crew undergo a psychological assessment before commencing line flying; a smaller operator may replace it with an internal assessment, scaled to its size, nature and complexity.
The paperwork that flies with you
Part-CAT then lists what must be carried on each flight, as originals or copies unless a form is specified, and the exam trades heavily on which is which. First the certificates and the aircraft's own papers:
The certificate of registration — as the original.
The certificate of airworthiness — as the original.
The aircraft radio licence — as the original, where one applies.
The AOC and its operations specifications — as a certified true copy, each with an English translation when issued in another language.
The noise certificate — including its English translation where the issuing authority provided one.
The third-party liability insurance certificate — proof the operator can answer for damage on the ground.
The journey log and the aircraft technical log — the aircraft's running records, the technical log kept per the continuing-airworthiness rules.
Then the manuals, which must be current and within the crew's reach:
The aircraft flight manual — or equivalent documents carrying the information required to operate within the certificate of airworthiness.
The operations-manual parts relevant to the crew's duties — easily accessible to the crew members.
The MEL — the minimum equipment list, whose workings get a lesson of its own later in the course.
And the information and forms assembled for this particular flight:
The operational flight plan and the filed ATS flight plan details — where applicable.
Current and suitable charts — for the route and every route a diversion may reasonably reach.
Interception procedures and visual signals — for use by intercepting and intercepted aircraft.
Search and rescue information — for the area of the flight, easily accessible in the flight crew compartment.
NOTAM and AIS briefing documentation, and the meteorological information — the briefing that flight preparation was built on.
Mass and balance documentation, and any manifests — cargo or passenger manifests where applicable.
Notification of special categories of passenger and special loads — where applicable, plus anything else the states concerned require.
Two reliefs soften the list. For day-VFR operations with other-than-complex aircraft that stay at one aerodrome or within a local area defined in the operations manual, several items, among them the noise certificate, radio licence, logs, briefing documentation and mass and balance papers, may be retained at the aerodrome instead of carried. And if the certificates or other listed papers are lost or stolen, the operation may continue to its destination, or to a place where replacement documents can be provided; an airliner is not grounded abroad by a stolen briefcase.
What stays on the ground
Mirror-imaging the flight file, the operator must keep information about the flight on the ground for at least the duration of each flight or series of flights: a copy of the operational flight plan, the relevant technical-log pages, route-specific NOTAM documentation the operator itself edited, mass and balance documentation and any special-loads notification. The point is grim and practical: if the aircraft is lost, the investigation must still be able to read what the flight intended. The information is kept until it has been duplicated at its permanent storage place, or, where that is impracticable, the same information flies in a fireproof container aboard the aircraft.
Access closes the loop. The commander shall, within a reasonable time of being asked by a person authorised by an authority, produce the documentation required to be carried. On the operator's side, every holder of operations-manual parts keeps a personal copy amended and up to date, and all operations personnel have easy access to the portions relevant to their duties: paperwork that cannot be produced, for a ramp inspector or for a crew member mid-briefing, might as well not exist.