8.3 Fuel Systems, Launch & Recovery Systems, Payloads & Maintenance Records

8.3 Fuel Systems, Launch & Recovery Systems, Payloads & Maintenance Records

Exam Focus: Most Small Basic candidates fly an electric multirotor that hand-launches and lands on its own legs, so they skip this material entirely. That is a mistake: TP 15263 ticks fuel systems, launch and recovery systems, payloads, and maintenance and record keeping in the Basic column. Expect questions on fuelling hazards, launcher and recovery safety areas, the payload prohibitions in CAR 901.43, and who may sign off which class of maintenance task.

---

Fuel Systems on Remotely Piloted Aircraft

Heavy-lift and long-endurance RPAs — agricultural sprayers, survey fixed-wings, hybrid VTOLs — often burn fuel rather than electrons, because liquid fuel carries roughly 40 to 50 times the energy per kilogram of a lithium-polymer cell.

Fuel System Types

Two fuel families dominate: glow fuel (methanol with nitromethane and lubricating oil, used in small two-stroke glow engines) and gasoline/oil premix (used in larger two-strokes). Both are far more flammable than automotive petrol in an enclosed space, and methanol burns with an almost invisible flame in daylight — a fire you cannot see is a fire you cannot back away from.

Fuel Quantity Measurement

Never infer remaining fuel from elapsed time alone; throttle setting, headwind, and payload all change consumption. Acceptable methods:

• Sight tube or translucent tank read at a known attitude on level ground.
• Calibrated dipstick for opaque tanks.
• In-line flow meter with a totalizer, cross-checked against a physical dip before every sortie.
• Weighing the aircraft before and after, for very small tanks.

Always plan a reserve — a minimum fuel state at which you break off the mission and recover — exactly as you plan a battery reserve.

Fuelling and Storage Technique

1. Stop the engine. Never refuel a running or hot engine.
2. Bond and ground. Flowing fuel generates static. Bond the container to the airframe and both to ground before opening the filler.
3. Move away from the launch point. Fuel at a designated fuelling area, downwind of and well clear of the take-off site, the crew, and the control station.
4. Approved containers only, clearly labelled, never glass, stored out of direct sun and away from ignition sources.
5. No smoking, no running generators, no hot work in the fuelling area; keep a suitable extinguisher within arm's reach.
6. Drain before transport. Fuel left in a tank inside a vehicle is a dangerous-goods problem and a vapour hazard.
7. Beware carbon monoxide. A running engine near a vehicle-based control station can fill that vehicle with CO. Position the ground station upwind of any running engine.

---

Launch and Recovery Systems

TP 15263 asks you to recognize the types and — more importantly — the safety areas and templates that surround them.

Types of Launchers

• Hand launch: the crew member becomes part of the hazard zone; brief a throw direction and a clear run-out lane.
• Bungee or elastic catapult: stores large energy in a stretched cord. A cord failure whips along the launch axis.
• Pneumatic or rail catapult: a compressed-air ram accelerates a carriage along a rail. The release corridor ahead of the rail and the carriage arrest zone are both lethal.
• VTOL / rotary launch: no launcher, but the rotor disc itself is the hazard.

Types of Recovery Systems

• Conventional landing on a prepared strip or pad.
• Deep stall: the aircraft is flown to a very high angle of attack so it descends steeply with low forward speed — a small footprint, but a high sink rate.
• Net or arresting system (hook and cable): stops the aircraft abruptly; the stanchion arc and the cable snap-back path are the hazards.
• Parachute recovery: deploys a canopy and descends under it. The drift cone is the critical planning item — descent footprint grows with deployment altitude and wind speed, so a 400 ft deployment in a 15 kt wind can drift the airframe well outside your fenced site.

Safety Template Rule: Draw the hazard geometry before the flight, not after the accident. For a catapult, the template is a cone extending forward along the launch axis. For a net, it is the arc swept by the stanchions plus the cable path. For a parachute, it is the downwind drift ellipse measured from the highest planned altitude. No crew member and no bystander stands inside a template.

---

Payloads

Sensor Types

The Payload Prohibitions (CAR 901.43)

No pilot shall operate an RPAS carrying a payload that:

• (b) includes weapons, ammunition or other equipment designed for use in war;
• (c) could create a hazard to aviation safety or cause injury to persons; or
• (d) is attached to the aircraft by means of a line, unless the operation is conducted in accordance with the applicable operating manuals.

CAR 901.43(2) allows any of these only under a special flight operations certificate — RPAS. Note the practical trap in paragraph (d): a slung camera on a lanyard, a tethered sampling hose, or a banner on a line is a line-attached payload. If the manual is silent, it is not permitted. Separately, CAR 901.50 prohibits creating a hazard to persons or property on the surface by dropping an object from an RPA in flight.

---

Maintenance, Task Classes and Record Keeping

The Three Task Classes

The Two-Person Perform/Verify Practice

For a critical task, one person performs the work and a second, independent person verifies it before flight. The point is not distrust — it is that assembly errors on control linkages and primary structure are frequently invisible on a single-person walk-around and fail catastrophically in flight. Record both names.

The Technical Log and Records

• CAR 901.29 bars take-off unless the aircraft is serviceable, all mandatory actions are complete in accordance with the manufacturer's (or declarant's) instructions, and all required equipment is installed and serviceable.
• CAR 901.48(1)(b) requires a record of any mandatory action and any other maintenance action, modification or repair, with who did it, when, and for a modification the manufacturer, model and description of the part — retained 24 months.
• CAR 901.48(3) requires the seller to deliver those maintenance records to the buyer at the time of transfer.
• CAR 901.51 requires the pilot of a declared model (one covered by a CAR 901.194 declaration with an acceptance letter under CAR 901.196) to report any reportable service difficulty to the declarant as soon as feasible.

Software and Firmware Version Control

Firmware on the aircraft and software on the control station form a tested pair. Two disciplines follow:

1. Log every version. Record the aircraft firmware and control-station app version in the technical log alongside the date.
2. Never update on site. Update at base, then fly a functional check flight over a safe area before committing the combination to a paying job. A mid-season firmware push that changes RTH behaviour is a genuine flight-safety event.

Flight simulation is the low-risk way to keep emergency handling current — practise ATTI-mode recovery, lost-link procedure and orientation-reversal drills in a simulator rather than over a client's roof.

---

Transporting Lithium Batteries (TDG Regulations)

Lithium-polymer and lithium-ion cells are Class 9 dangerous goods. The practical rules a Basic pilot must follow:

• Transport at a storage state of charge (commonly around 30 to 50 per cent, per the manufacturer), never fully charged.
• Protect the terminals against short circuit — tape, caps, or individual bags.
• Carry cells in a fire-resistant case, not loose in a camera bag with metal tools.
• Never transport a damaged, swollen or previously vented cell. Quarantine it and dispose of it through a battery recycler.
• On a passenger aircraft, spare lithium batteries travel in carry-on baggage only, subject to the carrier's watt-hour limits and quantity limits.
• Commercial shipment by road, rail, air or water is governed by the Transportation of Dangerous Goods Regulations, including documentation, marking and training requirements.