Clarification on similar

[twr75]

I would like some clarification (if possible) on the similar rule in order to avoid wasting everyone's time.

The guidelines state: "same registration, similar angle or composition or same background taken on different dates."

Similar angle - Is there a minimum angle to be considered different? Or just forget anything on the same side?
Same background - Given that most photos here are taken at an airfield, the next question will probably sound silly: What would be an example of a different background?

Thanks for taking the time to read this.

[Alex - Spot-This !]

Background needs to be really different. On your rejection Background wasn’t very significant, the angle was really too similar and the other picture was taken less than a year ago. All that on a very common plane.

Hope it helps
Alex

[twr75]

Thanks Alex.