Section 12: Maintenance & Inspections — Preflight Discipline, Battery Fires, and the Flyaway Plan

107.15 requires the preflight condition check; structure beyond that comes from the manufacturer or from you - and the exam's tested ordering is manufacturer FIRST, self-built only in its absence. The FAA's six tracked categories: overhaul, repairs, inspections, modifications, part replacements, software upgrades. His manned-aviation upgrade: a logbook per life-limited part (motor, prop, airframe), scheduled inspections at 50 hours, 100 hours, annually, and age-at-swap entries that surface failure TRENDS - props dying around hour 50 become predictable replacements instead of inflight failures. The receipt: DJI's Inspire TB50/TB55 cell-weakness saga, catchable early by exactly this tracking. Hours logging gets a forward-looking nudge: no minimums exist today, 'but who knows, in the future.'

The AC 107-2 list, condensed: visual condition - registration marking visible externally, control surfaces and linkages, props and motors ('power plants'); the control station - antennas and sticks; adequate energy across ALL systems; transceiver and control link including camera feed; ground gear (retractable landing gear on the bigger craft). The flagged trap: compass calibration is NOT routine - only when the manufacturer's system prescribes it or after significant travel. Configuration checks: RTH/flight-termination altitude set; payload secured; GPS acquired - four satellites minimum for a 3D fix, more for precision.

Then the live checks: spin the props listening for imbalance, vibration, uneven noise; confirm heading and altitude read sensibly (zero on the ground); scan for obstructions; and fly a LOW-ALTITUDE stability and range check before climbing - 'don't just go and gun it and then go all the way up.'

Thermal runaway: one overheated cell starts a chemical fire, and 'once one of these cells goes off, then it triggers all of the other ones' - the hoverboard-video mechanism. Because it's heat-driven, extinguishing the FLAME isn't extinguishing the FIRE: Halon removes oxygen and stops flames but leaves the cell hot; water both extinguishes and COOLS - which is why it's preferred, and why even after Halon you still pour water. The exam's sharpest trap: never ice - it insulates, trapping the heat that drives the runaway, and the fire relights beneath it. Handling rule verbatim: don't pick up a smoking or burning battery - water it where it lies.

Preflight the batteries themselves: crushing, bad charging, and defects all breed fire risk, and BLOAT is the visible verdict - a puffed pack that no longer fits is dead, never forced, never flown, disposed per local regulation. The travel rule with a fatal history: lithium flies CARRY-ON only, never checked - a thermal runaway in a cargo hold is unreachable and has brought down aircraft.

The radio reality: most UAS split 2.4 GHz (usually video) and 5.8 GHz (usually control) - shared consumer bands, line-of-sight physics; an obstacle between you and the aircraft IS a signal event. Loss-of-link planning means knowing the specific behavior: hover, RTH (at what climb altitude?), mission-continue, land, or motor cut. The cautionary tale from his news beat: an unreported flyaway that dead-sticked onto Las Vegas airport property, traced by the FAA, fined five figures - flyaways in controlled airspace get REPORTED, always.

The counterweight power: in a genuine emergency the remote PIC 'is actually allowed to deviate from any of the regulation to respond' - break the rule, save the person, file the paperwork after. Emergency procedures get briefed to every crew member before launch, not invented during.