How to buy a helicopter
Category A or Category B decides what missions the aircraft can fly, and the retirement times on rotating parts decide what it costs to keep. Both are readable before you call a salesman.
This category holds the manufacturers of helicopters, tiltrotors and other vertical lift aircraft. Maintenance on them is a separate guide, and a company that adds a hoist, a camera turret or a medical interior to somebody else's airframe is a modification house. What follows is the part of the purchase that is fixed by the certification basis, which is to say the part a buyer cannot negotiate afterwards.
Normal category and transport category are different aircraft
Part 27 prescribes the standards for normal category rotorcraft with a maximum weight of 7,000 pounds or less and nine or fewer passenger seats, and a multiengine rotorcraft may be type certificated as Category A where the requirements referenced in the part's own appendix are met.1 Part 27 does not force it. Part 29 covers transport category rotorcraft, which must be certificated as Category A or Category B, and a multiengine machine may hold both with different operating limitations for each.2 Above 20,000 pounds with ten or more passenger seats, Category A is mandatory.2 Category A is the engine-out case, and the part writes it out in its own sections: takeoff decision point, rejected takeoff, takeoff path and elevated heliport takeoff path.2 If your plan puts the aircraft on a rooftop, an oil platform or a confined site, read the flight manual's Category A charts at your real weights and temperatures before anything else in the pitch.
The mission drives equipment that is not free
External load work is its own certificate. Part 133 prescribes both the airworthiness certification rules for rotorcraft used in external-load operations and the operating and certification rules for the work itself.3 Air ambulance work is heavier still: a helicopter in air ambulance operations must carry an approved flight data monitoring system capable of recording flight performance data, and the subpart adds terrain awareness and warning equipment, VFR ceiling and visibility minimums in Class G airspace, a pre-flight risk analysis, and an operations control centre once a certificate holder has ten or more air ambulance helicopters on its operations specifications.4 None of that is optional, all of it has weight and cost, and much of it must be installed under an approval somebody holds. Specify the aircraft against the mission rule, not against the base model.
Retirement times are the real operating cost
A helicopter's direct cost is dominated by components that come off on a calendar or a count, not on condition. Those replacement times and inspection intervals live in the airworthiness limitations section of the rotorcraft maintenance manual, and a type certificate holder that gets a change to any replacement time or interval approved must make it available on request to any operator of the same type of rotorcraft.5 So ask for the current airworthiness limitations, build the retirement schedule for the serial numbers you are being offered, and price it over your planned hours. Two used aircraft at the same price are rarely the same purchase once that table is filled in.
Questions that sort sellers
Ask which category the aircraft is certificated in and what performance class your operation actually requires. Ask for the hover performance at your density altitude and mission weight, from the flight manual. Ask which mission equipment is installed under whose approval, and whether it is approved on this model and this configuration. Ask for the component retirement list with hours and dates remaining, and for the last three unscheduled removals.
The companies below are listed on public facts, each with its source linked.
Sources, in the order cited
- 1Electronic Code of Federal Regulations · 14 CFR Part 27, Airworthiness Standards, Normal Category Rotorcraft
- 2Electronic Code of Federal Regulations · 14 CFR Part 29, Airworthiness Standards, Transport Category Rotorcraft
- 3Electronic Code of Federal Regulations · 14 CFR Part 133, Rotorcraft External-Load Operations
- 4Electronic Code of Federal Regulations · 14 CFR Part 135 Subpart L, Helicopter Air Ambulance Equipment and Operations
- 5Electronic Code of Federal Regulations · 14 CFR 21.50, Instructions for Continued Airworthiness and airworthiness limitations