FAA Part 107 Remote Pilot (UAG)OperationsMedium
A remote pilot is preparing to launch a sUAS near a runway threshold moments after a departing airliner has rotated and climbed out. What hazard should the pilot be most concerned about?
- ARadio frequency interference from the airliner
- BWake turbulence from wingtip vortices
- CBird strike probability increasing
- DGPS multipath error near the runway
Show answer & explanationAnswer & explanation
Correct answer: B. Wake turbulence from wingtip vortices
Wingtip vortices generated by larger aircraft can persist for minutes and create strong rolling forces capable of upsetting a small, lightweight UAS, making wake turbulence the primary hazard shortly after a large aircraft's departure.
Why the other options are wrong
- A. Airliners are not a typical source of RF interference to sUAS control links.
- C. Bird activity is not specifically tied to a recent departure.
- D. GPS multipath is caused by structures/terrain reflecting signals, not aircraft departures.
Wake Turbulence
Rotating air masses (wingtip vortices) generated by aircraft, strongest behind heavy, slow, clean aircraft, posing upset risk to lightweight sUAS.
- Vortices sink and drift with wind after generation
- Most hazardous behind heavy aircraft during takeoff/landing
- Small, lightweight UAS are especially vulnerable to upset
Memory trick: 'Big planes leave invisible tornadoes behind.'