The crest of the pulse can be calculated as: V = I × Z. To do this, an air terminal (or system of air terminals) is placed in the most probable position to capture the direct strike, based on the structure’s architectural design and roof equipment. When an airplane is struck by lightning and the strike is evident to the pilot, the pilot must determine whether the flight will continue to its destination or be diverted to an alternate airport for inspection and possible repair. 3). While the electrical system in an airplane is designed to be resistant to lightning strikes, a strike of unusually high intensity can damage components such as electrically controlled fuel valves, generators, power feeders, and electrical distribution systems. Perform typical external surface examination for Zone 1 and Zone 2. This surge protection is limited, however. A three year prospective audit of 212 presentations to the emergency department after electrical injury with a management protocol. 9). We are experts in our field, installing lightning protection systems that comply with the industry-recognised safety standards: BS 6651:1999, BSEN 62305-2011 and NF C 17 102. 7). All areas of the airplane surfaces where a first return stroke of reduced amplitude is likely during lightning channel attachment with a low expectation of flash hang on. A survey of U.S. commercial jets showed that most lightning strikes occur between altitudes of 5,000 feet (1,524 meters) and 15,000 feet (4,572 meters). The electrical system of a home or business is one of the most frequent points of entry of increased voltage from a lightning or surge event. 20-136B - Aircraft Electrical and Electronic System Lightning Protection Date Issued September 07, 2011 Responsible Office AIR-130, Aviation Safety - Aircraft Certification Service, Aircraft Engineering Division Description. Perform a check of the standby compass system only if the flight crew reported a very large compass deviation. This rate is frequent enough for a lightning strike to be considered almost inevitable. A single bolt of lightning can contain as much as 1 million volts or 30,000 amps. Another indication of lightning strike is damage caused to bonding straps. Other Electrical Systems 3. Data was gathered from airlines with 881 strikes reported. Lightning strikes to airplanes can affect structure at the entrance and exit points. This ionization is caused by an increase in the electromagnetic field density at those locations. Additional inspections for Zone 3 include: Note: This is an outline of inspection procedures. Conditions that cause precipitation may also cause electrical storage of energy in clouds. The highest probability for lightning attachment to an airplane is the outer extremities, such as the wing tip, nose, or rudder. If lightning strikes an airplane, a lightning-strike conditional inspection must be performed to locate the lightning-strike entrance and exit points. Boeing recommends that a lightning-strike conditional inspection be performed prior to the next flight to maintain the airplane in an airworthy condition. Boeing performs testing that ensures the adequacy of lightning protection. This damage is often in the form of burnt paint, damaged fiber, and composite layer removal (see fig. In summary, any entrance and exit points must be identified in Zones 1, 2, or 3 so that the immediate areas around them can be thoroughly examined and repaired if necessary. Image courtesy of NASA. The level of uncertainty connected to what damage has taken place because of a lightning strike is indicative of why going it alone should always be seen as a bad strategy. Source: Figure 2 is adapted from Airlines Lightning Strike Reports Project: Pilot Reports and Lightning Effects by J. Anderson Plummer, Lightning Technologies Inc., Aug. 2001. Because the airplane flies more than its own length during the time it takes a strike to begin and finish, the entry point will change as the flash reattaches to other spots aft of the initial entry point. For systems not operated by the flight crew in flight or systems where anomalies were found, additional operational test procedures, as specified in the respective AMM, may be required. Airplanes that fly short routes in areas with high incidence of lightning activity are likely to be struck more often than long-haul airplanes operating in more benign lightning environments. Areas of an airplane that are prone to lightning strikes are indicated by zone. Examine the metallic and nonmetallic structure for damage. Similarly, our electrical services earthing complies with the BS 7430 1998 Standard. Blackwell N, Hayllar J. Areas of low activity are white, gray, purple, and blue. That affordable electrician has been trained rigorously to conduct the sort of tests around a home that can immediately spot any problem areas. Where: V is the crest voltage I is the peak lightning current Things to Check After a Lightning Strike. For example, in the United States, parts of Florida average 100 thunderstorm days per year, while most of the West Coast averages only 10 thunderstorm days per year. These guys spent 2-3hrs performing this test, removing GFCI's, fan switches etc. Our engineers will undertake remedial and maintenance work at virtually any height, and are trained in the safe and … It is highest over warm continental areas. For example, if all the navigation and communications systems are operated by the flight crew in flight after the lightning strike and no anomalies are found, checks to the operated systems would not normally be required. For these reasons, Boeing recommends that a complete lightning-strike conditional inspection should be performed prior to the next flight to maintain the airplane in an airworthy condition. Here are some of the most common problems caused by lightning. Our depth of knowledge when it comes to an electrical inspection after lighting strikes or any inspection after surge damage has occurred is invaluable during what’s invariably a tenuous time in your life. The reason is that lightning activity is more prevalent between 5,000 to 15,000 feet (1,524 to 4,572 meters) altitude (see fig. Damage to wiring within the walls of a home is particularly insidious. The conditional inspection is necessary to identify any structural damage and system damage prior to return to service. Examine the external surfaces carefully to find the entrance and exit points of the lightning strike and look in the areas where one surface stops and another surface starts. The prospect of tragedy largely relates to being directly hit by lightning, but individuals will remain in danger until all electrical issues have been properly addressed. Boeing provides lightning-strike inspection procedures to ensure external surfaces have not been damaged. The amount and type of damage an airplane experiences when struck by lightning can vary greatly, depending on factors such as the energy level of the strike, the attachment and exit locations, and the duration of the strike. on-board electrical systems as well as mechanical damage on the structural materials. In reality, many strikes can render this piece of equipment useless in the blink of an eye and cause confusion during a moment of crisis. However, an affordable electrician is really only a phone call away. Postgrad Med J. We perform many types of static electricity tests. Having a basic understanding of lightning strikes will assist technicians in performing effective maintenance. It’s your best approach to tracking down the problem(s). Because of these variations among lightning-strike events, it can be expected that the more often an airplane gets hit by severe lightning, the more likely it is that some of those events will result in damage levels that may require repair.