Lift/Drag ratio chart
Most aircraft accidents occur during the take-off or landing phase of the flight. Collisions with obstacles during climb out, runway overruns on landing do occur every now and then. In this section of the site we will take a look at the various factors contributing to the performance of the aircraft in this part of the flight.
A pilot uses best glide speed when he needs to fly the longest distance per unit of altitude lost. It is also used when the engine fails and a suitable landing place must be reached. Best glide speed is at that point where the lift/drag ratio is at its highest.
For most pilots forced landings are usually practiced only near a suitable runway as engine failures are a rare occurrence. But as practice tends to make perfect, it is time to review the finer points of this important excersize.
Forced Landing Without Power
A maneuver often practiced during training for the license and usually only when the pilot is up for the biannual flight review. We touch on this subject as it is intimately related to best glide speed.
Basically it boils downs to this: always be aware of the wind direction and fly in such a way (altitude and ground track) that you are able to reach a suitable landing spot at anytime. And if the engine does fail then this is what you should do after converting excess speed to altitude and trimming for best glide speed.
During initial descent
- Check wind direction
- Select landing site and take note of obstacles
- Plan the 1500' and 1000' downwind points
- Choose 1/3 aim point
- Fuel pump on, change tanks / contents, primer locked
- Mixture rich, carb heat on
- Ignition BOTH-RIGHT-LEFT-BOTH checks, attempt a restart
- Partial power checks
- Keep field insight / warm engine (during training), fly to 1500' point
- 3 x call, ATC, callsign, nature of problem, position, heading, altitude
- Set transponder to 7700
- Fly from 1500' to 1000' point, maintain best glide speed, monitor descent, keep one eye on your landing site
- Hatches closed, harnesses adjusted, check for loose items and nearest house for help
- Emergency equipment: location of axe, fire extinguisher, first aid kit, doors
- Fuel off, mixture lean, ignition off, master off (not if flaps are electrical powered)
- Warm engine at this point during training
At 1000' point
- Turn to landing area, keep field on wing tip
- Check wind, maintain best glide speed, set flaps as required
- Land as short as possible, ground loop if required
- Evacuate, secure aircraft, attend to injuries, obtain help
Practice this regularly as one fine day (or not) you might need it and its best to be proficient and mentally ready for the challenge.
Being aware of the available emergency and search and rescue services for pilot might be a lifesaver one day. Read more in our article on Emergency Services.