Help with VFR scanning techniques
Help with VFR scanning techniques
Guest
Posts: n/a
Umm....what exactly would you like to scan....Trevor Thom says a bit about this.
When looking out never keep your eyes still....you must be looking at all parts of the sky all the time....even if its only for other traffic and not for ground features. Head down time should be kept to a minimum. Scan the map (always keep the map pointing the way you are going it makes things easier
). And just go over the instruments on the way back up...thats how i do it. Oh and a FREDA check now and then.
Hope that helps
Tom
When looking out never keep your eyes still....you must be looking at all parts of the sky all the time....even if its only for other traffic and not for ground features. Head down time should be kept to a minimum. Scan the map (always keep the map pointing the way you are going it makes things easier
). And just go over the instruments on the way back up...thats how i do it. Oh and a FREDA check now and then. Hope that helps
Tom
Joined: Aug 1998
Aviation Qualifications: ATPL
Posts: 6,623
Likes: 847
From: Ex-pat Aussie in the UK
For a visual scan for traffic aircraft that are on a collision course remain at a constant relative bearing only increasing in size not moving across the visual field.
The eye is constructed so that the field of view is around 120° horizontally and 150° vertically, however only the centre of the vision area (the fovea) can detect the sort of detail we need to see aircraft - the rest is designed to detect movement (like big nasty predators!).
In addition to this without anything to focus on (i.e. looking at an empty sky), an eye will relax to its natural focus point of around one to two metres. This makes the pilot short sighted (known as empty field myopia) so that aircraft out the window are out of focus, and even harder to detect.
Finally, the eye doesn't move in a smooth scan, but "jerks" from poistion to position (known as "saccades"), which each "jerk" taking about a third of a second.
Given these points, for a good visual scan you need to:
The eye is constructed so that the field of view is around 120° horizontally and 150° vertically, however only the centre of the vision area (the fovea) can detect the sort of detail we need to see aircraft - the rest is designed to detect movement (like big nasty predators!).
In addition to this without anything to focus on (i.e. looking at an empty sky), an eye will relax to its natural focus point of around one to two metres. This makes the pilot short sighted (known as empty field myopia) so that aircraft out the window are out of focus, and even harder to detect.
Finally, the eye doesn't move in a smooth scan, but "jerks" from poistion to position (known as "saccades"), which each "jerk" taking about a third of a second.
Given these points, for a good visual scan you need to:
- Move your scan from point to point, covering about 10° of the field of view with each movement.
- regularly focus on distant objects (like hills or clouds) to avoid empty field myopia. and
- hope you have a good radar service / TCAS
Joined: Apr 2002
Posts: 201
Likes: 0
From: MNL ex CCR ex CLE
One scanning technique that was taught to me by a cousin who used to fly F-4's for the Navy during my PPL training works very well and has served me thru the years. If you have VFR flight following services (always nice to have,but DON'T be overly reliant on it!),i.e. "traffic 5 miles...." first focus out at 5 miles distance and THEN look for the target. This method helps to alleviate the empty field myopia affect mentioned in an earlier post.
