Embraer EMB145, Operation Manual

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AIRPLANE
OPERATIONS
MANUAL
SUPPLEMENTARY
PROCEDURES
ENVIRONMENTAL
REVISION 41
1-02-79
Page
27
Code
01
Copyright © by Embraer. Refer to cover page for details.
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Altitude: strikes are more intercepted between 5000 and 15000 ft,
but may occur at virtually all flight altitudes. Lightning strike
incidents at lower altitudes are far more frequent since at higher
altitudes airplanes can divert around thunderclouds with greater
ease.
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Outside air temperature: most strike incidents have occurred when
the airplane is flying in temperatures near or at freezing level.
Strikes may also occur at temperatures as high as 25°C, or as low
as -45°C.
Metal airplanes produce a phenomenon called Faraday Cage effect,
which distributes electrical charges along the airframe in such a
manner that occupants and internal components will not receive the
high current that causes injury and damage. There seems to be no
record of any case of crew incapacitation due to lightning, although
flash blindness can occur for a few seconds.
Direct effects which result from lightning current attachment to and
flow through the airplane may be:
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Pit marks are often seen along the fuselage or holes in the trailing
edge of wing and tail tips.
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Melting of rivets.
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Puncturing of nonmetallic structures.
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Puncturing and de-lamination of composites.
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Slight deformation of metal skins and structure.
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Welding or roughening of moveable hinges and bearings.
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Damage to other parts that may conduct lightning current other
than the airframe, such as bonding or diverted straps and pitot
tubes.
Effects caused by the flash-induced electromagnetic field and the
increase of the voltage due to the current at the airplane structure are
defined as indirect effects and may be:
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Interruption of instruments and navigation equipment.
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Damage to electronic and electrical equipment.
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Popping of circuit breakers.
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Loss of electrical power.
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Engine flame-out.
In case of lightning strike, report the incident to the maintenance
personnel, by filling out the LIGHTNING STRIKE REPORT (Abnormal
Procedures - Section 1-03-70 - Miscellaneous).