TM 55-4920-390-13&P
NOTE2
Avoid touching adhesive backing on numbers, for oily fingerprints spoil adhesion.
NOTE 3
Low temperature adversely affects adhesion. The lowest temperature for application of the
numbers is 40to 50F.
b) As an alternate to 4-5, a, a bracket must be secured to each blade tip. These brackets shall extend vertically
downward from the underside of the blade about 1", and shall be aligned tangent to the tip path. To the inside
face of these brackets shall be secured the retro-reflective tip targets. (It is best to fix the targets to the brackets
before the brackets are secured to the blade tips.) The targets may be any one of several forms such as:
1) Numbers (1 " high) one for each blade. See Figs. 4-4 & 4-5
2) Colors, a different one for each blade. Color blindness of the operator can be a problem, and poor
uniformity of reflection from the different colors is another.
3) Shapes, a different one for each blade, such as
In each case, the material must be retro-reflective.
NOTE
With this method, each aircraft will require a different bracket to accommodate available screw
hole patterns, etc.
4-6. HEUCOPTER TO REMAIN EQUIPPED . It is recommended that the helicopter be left equipped, as in 4-3 thru 4-5,
at all times. This keeps tracking time to bare minutes. (The decision to keep tip tabs (4-5, b) on the aircraft during
service must be the choice of the using agency.)
4-3
