Overview
The term slipstream refers to the airflow accelerated rearwards by an aircraft’s propellers or jet exhaust and the associated wake that travels behind the aircraft. At aerodromes, understanding slipstream is critical for safe ground operations, helicopter and light-aircraft handling, hangar positioning, and runway/taxiway procedures. Slipstream effects range from subtle buffeting to strong crossflows that can move loose objects, disturb small aircraft, and affect following traffic.
How slipstream forms
Slipstream originates from two primary sources: propeller rotation (for piston- and turboprop-driven aircraft) and jet exhaust/wake turbulence from turbofan or turbojet engines. Propellers impart rotational flow and accelerate air rearwards; jets create high-velocity exhaust and vortices. These flows interact with ambient air and with the ground, producing complex patterns including helical slipstreams, wing-tip vortices, and turbulent wakes.
Operational impact at aerodromes
- Ground personnel safety: Strong slipstream can knock over service vehicles, trolleys, cones, and unsecured equipment.
- Aircraft movement: Light aircraft and helicopters near runways or taxiways can experience control difficulties when hit by slipstream or wake from larger aircraft.
- Pilot procedures: Pilots must consider recommended separation times and approach corridors to avoid encountering hazardous wake turbulence.
- Infrastructure: Aircraft exhaust and displacement can accelerate debris ingestion risk for engines if foreign objects are blown into intakes.
Safety guidelines & best practices
Airports and operators adopt several simple, effective measures to reduce slipstream hazards:
- Enforce minimum spacing between departing and arriving aircraft, especially when heavy jets follow lighter types.
- Secure ground equipment and cover sensitive components on nearby aircraft during engine run-ups.
- Designate personnel-safe zones and use signage to keep crews clear of high-velocity exhaust areas.
- Include slipstream awareness in pilot briefings, emphasizing approach path and avoidance of vortices from larger aircraft.
Note: Local airport operating procedures may specify additional or more conservative rules—always follow the aerodrome's published guidance.
Practical tips for pilots & ground crews
- During engine run-up, face the aircraft into the wind where possible to reduce the slipstream’s lateral reach.
- When taxiing behind larger aircraft, stay outside the wake vortex core—typically offset from the runway centerline.
- Use chocks and tie-downs for parked small aircraft if heavy traffic activity is expected.
- Ground crews should maintain eye contact with flight crews and use clear hand signals when moving within potential slipstream zones.
Conclusion
The aerodrome slipstream is an invisible but powerful factor in airport operations. Predictable when informed by aircraft type, engine setting, and wind, it becomes a manageable risk with good procedures, communication and a culture of awareness. Whether you’re a pilot, ground handler, or operations manager, paying attention to slipstream behavior protects lives, equipment, and keeps operations running smoothly.