Embraer EMB145 Operation Manual page 2564

NAVIGATION AND
COMMUNICATION
RADOME
The radome is the primary factor behind degraded weather radar
performance. The problems affecting the radome are as follows:
-
A water film over the radome's surface when flying in rain.
-
Greased radome.
-
Cracked radome.
-
Holes caused by lightning strike/electrostatic discharges.
-
Excessive application of antistatic paint.
Water Film Over The Radome's Surface: When flying in rain, there
is indication that at some specific altitudes and speeds a water film is
formed on the radome, altering the weather radar indications. The
radar display may disappear or turn red. To avoid this problem, there
is a hydrophobic coating product named Cytonix
to the radome surface.
Greased Radome: The presence of grease or dirt over the radome's
surface also impairs radar transmission. These should be reported
immediately to maintenance personnel for cleaning or corrective
action.
Electrostatic
performance.
accomplished through two metallic meshes that link the radome's
metallic bulkhead (diverters) to the airplane's airframe. It is important
to make sure that they are in good condition and not painted. If both
the metallic meshes and screws are painted, this will isolate the static
power generated in the radome, resulting in electrical discharges that
will follow towards the radar antenna and/or generate noise in the
audio system.
Cracked Radome: Small holes caused by electrostatic discharges,
minor damage to structure or paint can cause water infiltration in the
radome's honeycomb composite structure. It can result in significant
radar signal attenuation, distortion and in some cases, can cause dark
spots on the radar screen.
Page
18
2-18-45
AIRPLANE
OPERATIONS
MANUAL
Discharges:
The right bonding
Code
01
Static electricity
is necessary.
®
that can be applied
influences
Bonding
REVISION 38
radar
is