Name 4 types of viewing tips on a borescope tool?

Question

Name 4 types of viewing tips on a borescope tool?

Answer 1

Why is this in the aircraft section? hmmmm?

Answer 2

1st guy got it

Answer 3

90 degree, 120 degree, 90 and 120 degree mirror tubes

Answer 4

Borescopes have become indispensable in conducting proper inspection in tight inaccessible areas. hmmmmm

One basic consideration is chose of rigid or flexible.  In an unknown environment, flexibility come in handy to negotiate any curves or changes in direction. But flexibility of the tubes can sometimes reduce image quality. In known areas, like the inside of an engine, mechanics prefer rigid tubes because images are better, making diagnostics easier.

Both size and pixilation are important considerations. Anything under 10,000 pixels should not be considered. The norm for flexible borescopes is 15,000 to 24,000 pixels.

Size is of special consideration when selecting rigid borescopes. Objective lenses are classified by type. There are three kinds: achromatic doublets, Hopkins rods and gradient index lenses. If a borescope needs to be especially small in circumference, gradient index lenses are the best choice. Hopkins rods work well for medium spaces, and achromatic lenses are generally chosen for the largest spaces.

Light, in lumen's and disbursement is significant and critical.   Surface reflection can destroy the image even if everything else is correct.  In fact when inspecting an area for the first time I believe this is the worst because it's trial and error.

To answer the question why the question why this is in Aviation, most modern commercial aircraft and military aircraft would not be able to fly as many necessary inspections, inclusive of Preflight Inspection couldn't be completed in compliance with regulations..

NOTE Since there are always certified critics of genuine information I took time to get 4 reference of FAA inspections requiring the use of Bore Scopes. 2 from maintenance facilities and 2 FAA directives;

http://www.aeroinspection.com/index.php?...

http://edocket.access.gpo.gov/2006/06-82...

http://rgl.faa.gov/Regulatory_and_Guidan...

http://a257.g.akamaitech.net/7/257/2422/...