Glide Extension

Glide Extension

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Glide Science

Glide extension refers to techniques pilots use to increase the distance an aircraft can glide after engine failure. These techniques are critical for maximizing reach to a safe landing location.

Best Glide Speed (L/D Max)

This is the airspeed at which the aircraft can cover the greatest distance for each unit of altitude lost.

• Pilots should be familiar with their aircraft’s best glide speed, typically listed in the Pilot Operating Handbook (POH).
• Maintaining this speed ensures the aircraft glides efficiently and maximizes distance.

Wind Conditions

• Tailwinds increase ground speed, allowing the aircraft to cover more distance in the same time.
• Headwinds reduce ground speed, decreasing effective glide range.
• Pilots must account for wind direction and speed when planning a glide.

Other Factors

• Altitude: Higher altitude at engine failure increases potential glide distance.
• Aircraft Design: Different aircraft have different glide ratios.
• Flaps: Increase drag and reduce glide performance; should be retracted.
• Propellers: Coarse pitch (low RPM) reduces drag in aircraft with constant-speed propellers.

Glide Ratio

The glide ratio is the distance an aircraft travels horizontally for every unit of altitude lost.

• Higher glide ratios result in greater glide distance.
• A common estimate: 1.5 nautical miles per 1000 feet of altitude.

Glide Distance Calculation

To estimate glide distance:

Glide Distance (NM) = Glide Ratio * Altitude (ft) / 1000

• Example: A glide ratio of 1.5 at 5000 feet gives a distance of 7.5 NM.

Configuration Tips for Glide Extension

Based on Flight Safety Australia:

• Maintain proper configuration: gear up, flaps retracted, cowl flaps closed.
• Reduce propeller RPM to decrease drag (if equipped).
• Avoid skidding/slipping turns, maintain coordinated flight.
• Fine-tune speed based on aircraft weight and conditions.

Practical Advice

• Visualize your glide range like a ring around the aircraft.
• Practice transitions from best glide speed to landing configuration.
• In some aircraft, leaving the gear up until landing surface is assured is advised.
• Practice "Power-off 180" maneuvers and short-field landings for proficiency.

References

• SKYbrary
• Flight Safety Australia