Vad är designmotståndet med låg motstånd i ett flygplan för att motstå en blixtnedslag?

Den ledande yttre kroppen

Nästan alla flygplan har metallkroppar, strömmen strömmar genom den yttre metallen.

Flygplan med kompositskrov kan ha ledande material som läggs till kompositerna för att ge en väg för blixtnedslag. Detta är vanligtvis ett metallnät.

Vissa mindre kompositflygplan, som saknar denna typ av försörjning, kan helt enkelt inte flyga nära moln eller någonstans där det finns risk för blixtnedslag.

fotoavBoeing-sereferenser

Denyttreledandeytanfungerarsomen Faraday bur som hindrar höga spänningar och strömmar från att påverka interiören.

enFaradayburfotoav Antoine Taveneaux

It is estimated that on average, each airplane in the U.S. commercial fleet is struck lightly by lightning more than once each year.

Initially, the lightning will attach to an extremity such as the nose or wing tip. The airplane then flies through the lightning flash, which reattaches itself to the fuselage at other locations while the airplane is in the electric "circuit" between the cloud regions of opposite polarity. The current will travel through the conductive exterior skin and structures of the aircraft and exit off some other extremity, such as the tail. Pilots occasionally report temporary flickering of lights or short-lived interference with instruments.

Every circuit and piece of equipment that is critical or essential to the safe flight and landing of an aircraft must be verified by the manufacturers to be protected against lightning in accordance with regulations set by the Federal Aviation Administration (FAA) or a similar authority in the country of the aircraft's origin.

Från Vetenskaplig amerikan - Vad händer när blixten träffar ett flygplan?

Planes are now built to absorb 250,000 amps, whereas the average strike generates 32,000 amps.

"It only gets really serious when the radome [nose cone] is struck, the only part of the plane's shell not made of metal, as this is where the radar is located. But nose cones have special lightning conductors for just this reason."

Från The Guardian - Skulle du vara orolig för blixtnedslag slår ditt plan?

The 787 flight test team gathered the unexpected data last month after one of the Dreamliner test aircaft was struck by lightning. Unlike traditional aluminum aircraft where the entire aircraft is conductive, on a composite airplane the charge from a lightning strike would find its way to the conductive parts such as wiring or hinges. In order to avoid the risk of the charge damaging these kinds of parts, Boeing had to add conductive material to the composites in order to provide a pathway for lightning strikes.

Från Boeing 787 motstår blixtnedslag

Andra referenser

• Boeing - blixtnedslag, skydd, inspektion och reparation
• Skydda 787
• Strålskyddsstrategier för kompositflygplan