8 Emergency Procedures
In manned aviation, the steps you are taught in an emergency situation goes like this: Aviate, Navigate, Communicate. Aviate, meaning fly your aircraft first, follow the checklists on how to deal with a given emergency, and when you have control of the situation, then you move to the next issue: navigate. That means turn your aircraft toward the nearest airfield or begin looking for the nearest safe landing space (a field, an empty road, etc). After you have identified a safe place to attempt a landing, then you communicate with ATC alerting them to your situation.
Drones are going to be similar, but the altitudes are going to be much lower, the time is going to be much shorter, and the communicating you do will likely only be with people in the immediate vicinity.
The important part about dealing with an emergency is being prepared for one. Some UAS manuals will have guides on how to deal with certain emergencies. The PIC should be familiar with those before they fly.
The PIC is responsible for giving a pre-flight briefing to all involved in the flight. Part of that pre-flight briefing is going over emergency procedures.
Prior to flight, the PIC should say how an emergency would be declared and what is expected of each member of the flight crew.
Common types of UAS emergencies and remedies:
| Emergency | Action |
|---|---|
| Motor failure | Begin immediate landing away from people, alert anyone in immediate area |
| Power failure | Alert anyone in immediate area |
| Loss of aircraft control link | Follow instructions on re-establishing, observe Return To Home engaged |
| Loss of GPS | Establish control and begin return flight to takeoff area |
Remember: Aviate, Navigate, Communicate. In an emergency, the PIC is responsible for the safety of those around the UAS. Their first job is to get the UAS under control (Aviate) and move it toward an optimally safe place to land (Navigate). After that, the PIC will communicate with other flight crew or warn nearby people if there is time.
Remember two things from Part 107: In an emergency, you can deviate from any regulation to the extent necessary to handle the emergency safely. And if you do crash, you have to report it to the FAA if someone is significantly injured or more than $500 in property damage is done beyond your drone. If your drone crashes into an empty parking lot, you do not have to report it.
8.1 Working with lithium batteries
Under the Remote Pilot Certificate Airmen Certification Standard, the FAA says you must show knowledge of the characteristics and hazards of lithium batteries, including safe use and charging, potential hazards and the risks of fires. First and foremost, follow your manufacturers guidelines for charging and using your batteries. If a battery is damaged, misshapen or excessively heats up during use or recharging, stop using it.
The following comes from FAA safety alerts given to airlines that the standards reference.
- Each spare lithium battery must be individually protected so as to prevent short circuits (e.g., by placement in original retail packaging, by otherwise insulating terminals by taping over exposed terminals, or placing each battery in a separate plastic bag or protective pouch).
- Spare batteries must not come in contact with metal objects, such as coins, keys, or jewelry and take steps to prevent crushing, puncturing, or pressure on the battery.
- Overheating has the potential to create thermal runaway, a chain reaction leading to self-heating and release of a battery’s stored energy.
- Ignition of lithium metal batteries can be caused when a battery short circuits, is overcharged, is heated to extreme temperatures, is mishandled, or is otherwise defective.
- Once a cell is induced into thermal runaway, either by internal failure or by external means such as heating or physical damage, it generates sufficient heat to cause adjacent cells to go into thermal runaway.
- The result of thermal runaway in a lithium metal cell is a more severe event as compared to a lithium-ion cell in thermal runaway. The lithium metal cell releases a flammable electrolyte mixed with molten lithium metal, accompanied by a large pressure pulse. The combination of flammable electrolyte and the molten lithium metal can result in an explosive mixture.