No question that people have often been successful with improvised signal mirrors, though one's chances are greatly enhanced by being well practiced in the technique. I've practiced a lot with improvised signal mirror aiming methods.

The "somewhat lessened accuracy" was determined independently by the Yanks and the Brits to be more than a factor of four in tests that were far more thorough and scientific than I've had the resources to duplicate {Tests detailed in my prior post.}

The beam of sunlight is very narrow, and the average passerby is inattentive, and not really looking for you in the first place.

I figure I'm going to be lucky to get them to respond to the first half-dozen flashes they do see. I'm not inclined to give myself a handicap unnecessarily when the AMK Rescue Flash mirror in my neck pouch cost under $10 and weighs 0.7 oz.

CASE STUDY I

One of the authors of "The Complete Walker IV" learned the hard way that getting people's attention with an improvised signal mirror can be harder than you like, even in the very favorable circumstance that they are: looking for you, expect you to be using a signal mirror, and are in the neighborhood for a long time.

On pages 706-708 of that book, the author describes his experience in trying to get the attention of an airdrop plane with the pre-arranged signal: a 2" diameter mirror pointed using the "thumb" method taught him by the pilot, a former Air Force survival instructor. He practiced before the trip until he thought he had the technique down pat.

The plane arrived overhead, and started circling 2 miles away. There were at least two observers on the plane expecting and looking for his mirror flash. He signaled for a full hour without success. He finally got their attention with a smoke plume as they flew over him heading back to base.

He now carries a dedicated signal mirror.

CASE STUDY II

I interviewed by email one survivor who was finally successful in flashing a helicopter with a plain camp mirror, a gambit he was aware of because he was a dedicated reader of the survival articles in Backpacker magazine. He had been unsuccessfully flashing passing planes for days.

He asked me to recommend a signal mirror.