Could Lightning Have Downed Indonesia AirAsia Flight 8501?

The missing AirAsia flight QZ8501 carrying 162 people is presumed to have crashed off the Indonesian coast, an official said on Monday, as countries in the region offered to help Jakarta in the search-and-recovery effort. REUTERS/Beawiharta

On Sunday, CNN speculated lightning may have been partly responsible for the disappearance of AirAsia flight 8501 while en route from Singapore to Surabaya, Indonesia.

The commercial aircraft vanished from radar on December 28 with 155 passengers and 7 crew members on board. Indonesian search and rescue officials said they believe the plane is at the bottom of the Java Sea, a large but shallow body of water between Java, Sumatra, Malaysia and Indonesia.

Lightning bolts strike aircraft frequently but rarely cause significant harm, says Mike Dargi, general manager at NTS Pittsfield (formerly Lightning Technologies, Inc.), a research lab that tests various components for aircraft with "simulated lightning".

"Aircraft are struck and typically they survive quite well," Dargi says. "They're designed to survive lightning, and they're thoroughly tested for direct effects"—that is, the damage caused by lightning striking the exterior of an aircraft—"and indirect effects," or the damage lightning strikes can cause to an aircraft's delicate electronic instruments, he adds.

Although major commercial aircraft manufacturers like Boeing and Airbus continue to experiment with the idea of making aircraft hulls (or "skins," as the industry jargon goes) out of composite materials like fiberglass or carbon, most aircraft today have aluminum skins. Aluminum is very conductive of electricity, which may sound terrifying, but is actually quite useful. When lightning strikes the aluminum skin, it simply flows from one end of the plane to the other and jumps off again without ever touching the plane's electronics or, more importantly, its passengers.

Could AirAsia flight 8501's sensitive electronics have been damaged by a lightning strike? Probably not, says Richard Kithil, founder and CEO of the National Lightning Safety Institute, a Denver-based consulting, education, and research organization. "It's unlikely that lightning caused the malfunction of electronic systems, because they have been hardened with defenses for lightning protection for many, many years," he says.

Kithil thinks it's more likely the freezing of the plane's Pitot tubes is to blame. These tubes, named for French engineer Henri Pitot, measure an aircraft's speed. If they freeze, which is what happened in the case of Air France flight 447 from Paris to Rio de Janeiro in 2009—incorrect data can be fed to the pilot. In the case of Air France flight 447, the pilot was told the plane was going much faster than it actually was; he slowed the plane to a dangerously low speed, causing the plane to stall and crash. Something similar may have happened to AirAsia flight 8501, but all experts agree it is too early to tell conclusively.

"At this point, it's pure speculation," Dargi says.