Harmon Technologies, Inc.

Stormscope

Many large aircraft have on-board radar.  Contrary to popular belief, airborne radar is not normally used for navigation or to watch for other airplanes.  It is used to watch for weather.  In particular, the radar can be used to look for areas of intense rain (like in a thunderstorm) and avoid the worst areas.

For a variety of reasons, is is difficult to install conventional radar in single engine airplanes.  One reason is that the radar antenna and propeller need to be in the same place.  Weight (and cost) are other issues.

For these reasons, a different method of detecting thunderstorms was invented.  This technique uses a direction finding antenna mounted on the belly of the aircraft to listen for the crackle associated with lightning.  By watching the direction, strength, and timing, the direction and distance of the lightning can be estimated and displayed on a small radar-like video display on the instrument panel. 

Storms up to 100 miles away can be plotted and lightning strikes can be accumulated for several minutes to provide a picture of more and less active areas.

Stormscopes work so well that many airplanes that have radar also install stormscopes to provide a second opinion.  Radar sees rain but can't tell if the rain is associated with a thunderstorm.  Stormscops see lightning so they can specifically identify thunderstorms.

All airplanes (from small to very large airliners) need to avoid thunderstorms.  this is not because of lightning itself but because of the severe turbulence associated with them.  Pilots use many techniques to avoid thunderstorms (eyesight, guidance from air traffic controllers, and ground based radar information) but an on-board display is really a plus.  This equipment is usually found on larger and more expensive airplanes and N4907J is very fortunate to have this device on board to further enhance safety.

Copyright © 2004 Harmon Technologies, Inc.