Answer: There are many observed cases of lightning strikes to aircraft inside or near clouds that had not previously produced natural lightning. Studies show that about 90 percent of the lightning strikes to aircraft are thought to be initiated by the presence of the aircraft itself. The scary statistic, however, is that 40 percent of all discharges involving airborne aircraft occurred in areas where no thunderstorms were reported.

Apollo 12

One of the more famous cases of aircraft-initiated lightning is the Apollo 12 launch at the Kennedy Space Center, Florida, in November 1969. The Saturn V rocket was struck not once but twice on its way into orbit.

According to the 1970 NASA findings, other than these two strikes, there was no other lightning activity reported six hours before or six hours after the launch. At the time of the launch, a cold front was moving south into the launch area. Broken towering cumulus topping out at 23,000 feet with light to moderate rain showers were reported.

Rarely Fatal

Damage to airborne aircraft struck by lightning includes minor pitting or scarring to the aircraft’s skin to complete destruction of the aircraft.

Besides direct damage at the point of entry and/or exit, indirect effects that include the loss of VHF communication, loss of navigation equipment, and loss of instrument panel gauges are also possible.

In 1963, a Pan American Airlines Boeing 707 over Elkton, Maryland, was struck by lightning while in a holding pattern at 5,000 feet. The outermost fuel tank in the left wing exploded causing two other fuel tanks to follow suit. There were no survivors.  

• READ MORE: Does the FAA Punish Pilots for Logbook Mistakes?

It’s certainly true that a catastrophic accident such as this is extremely rare, but lightning strikes to aircraft are more common than you might imagine—most of which are aircraft-initiated strikes.

Based on compiled data it is estimated that in the U.S. a commercial airliner is struck once for every 3,000 hours flown. That’s an equivalent of about one strike each year. 

Melting Level

While aircraft-initiated lightning is still being actively studied, there are a few important characteristics to consider.

Based on the current research, it doesn’t take flying in or near a mature thunderstorm to become the victim of a lightning strike. The mere presence of the aircraft in an environment conducive to an electrical discharge is all that is necessary.

Most of the aircraft-initiated lightning strikes occur when the aircraft is flying at or near the melting level (0 degrees Celsius). The preferred temperatures include a range from plus-3 C to minus-5 C, with the highest number of incidents occurring right at the melting level.  

A few of the strikes down low are the result of an aircraft intercepting a lightning strike in progress. Essentially, this is the case of being in the wrong place at the wrong time.

On the other hand, aircraft-initiated strikes are observed the most are between 3 km and 5 km or 10,000 to 16,000 feet during the warm season. Once again, temperature is a key factor. The melting level that typically occurs is in this same range of altitudes throughout the summer months.  

Low-Topped Convection

In general, natural lightning in deep, moist convection doesn’t form until the tops of the storm build well above the melting level.

For lightning to form, three ingredients must be simultaneously present. These include vapor-born ice crystals, graupel, and supercooled liquid water. If any one of these three is missing in sufficient quantities, natural lightning doesn’t generally occur, but this not to say the cloud is void of all electrical activity—some still remains.    

Therefore, an aircraft-initiated lightning strike typically occurs within local air mass instability within low-topped convection.

Often low-topped convection doesn’t produce natural lightning. The updrafts are rather weak in comparison to those that do produce lightning. Consequently, the updrafts do not carry enough supercooled liquid water into the upper part of the cloud where it is needed. 

• READ MORE: What Are Echo Tops?

Clouds and Precipitation

An overwhelming number of lightning strikes occur within the cloud itself. Only a very small percentage of strikes occur outside of the cloud boundary or below the cloud.

Here’s the key: A very large percentage of the strikes occur within precipitation to include rain, snow, snow grains, ice pellets, and hail. It is not uncommon to find a mixture of these near the melting level. 

Keep Your Distance?

The FAA encourages all pilots to keep a safe distance from an active thunderstorm for obvious reasons.

Unfortunately, this practice alone isn’t quite enough. Even when thunderstorms (natural lightning) are not occurring or expected to occur, an aircraft-initiated lightning strike can still be a risk.

In order to avoid an encounter with lightning, the best advice is to remain in cloud-free air whenever possible, especially when the atmosphere is conditionally unstable and capable of producing marginally deep, moist convection extending well above the melting level.

While it may be difficult, the best advice is to operate outside of areas of precipitation and minimize your time in clouds and precipitation near the melting level.

The post How Can an Aircraft Get Struck by Lightning Without a Close Thunderstorm? appeared first on FLYING Magazine.

Answer: During the warm season, convective weather has a huge impact on the National Airspace System (NAS). As the amount of usable airspace diminishes on any given day, this ultimately engenders delays in the system. A departure within busy airspace usually means a delay. In the worst-case scenario, ground stops may be levied depending on route of flight and destination airport. Nevertheless, forecasters at the Aviation Weather Center (AWC) are busy at work issuing advisories to warn pilots of these dangerous convective areas.  

A single-cell, pulse-type thunderstorm is normally easy to spot in the distance and maneuver around while in flight. In this situation, a deviation around such a cell does not eat into your fuel reserves. However, when thunderstorms become embedded, severe, or dense in coverage within an area or along a line, they are considered a significant en route hazard to aviation. This often requires you to plan a more circuitous route, which means carrying extra fuel than if you flew a direct route. It is in this case that an AWC forecaster will issue a convective SIGMET (WST) to “protect” this airspace. 

When you hear “convective SIGMET” during your preflight briefing, don’t think of it as a forecast for thunderstorms. Instead, think of it as a “NOWcast” of organized convection that may be highly challenging or dangerous to penetrate. These active thunderstorms must meet specific criteria before a convective SIGMET is issued. Areas of widely scattered thunderstorms, such as shown in the XM-delivered satellite radar image below, are generally easy to see and avoid while in flight and often do not meet convective SIGMET criteria.

Nevertheless, on any particular eight-hour shift a single forecaster at the AWC’s convective SIGMET desk looks at all of the convective activity occurring throughout the conterminous U.S. on a continual basis. On an active convective weather day, they are likely the busiest forecaster on the planet. This forecaster is given the responsibility to subjectively determine if an area or line of convection represents a significant hazard to aviation using these minimum criteria:

• A line of thunderstorms is at least 60 miles long with thunderstorms affecting at least 40 percent of its length.
• An area of active thunderstorms is affecting at least 3,000 square miles covering at least 40 percent of the area concerned and exhibiting a very strong radar reflectivity intensity or a significant satellite or lightning signature.
• Embedded or severe thunderstorm(s) are expected to occur for more than 30 minutes during the valid period regardless of the size of the area. 

For reference, 3,000 square miles represents about 60 percent of the size of the state of Connecticut.

Will an advisory be issued as soon as the convection meets one or more of these criteria? Possibly. A special convective SIGMET may be issued when any of the following criteria are occurring or, in the judgment of a forecaster, expected to occur for more than 30 minutes of the valid period:

• Tornadoes, hail greater than or equal to three-quarters of an inch in diameter, or wind gusts greater than or equal to 50 knots are reported.
• Indications of rapidly changing conditions, if in a forecaster’s judgment they are not sufficiently described in existing convective SIGMETs.

However, special issuances are not the norm, especially when there is a lot of convective activity to capture. In most cases, a convective SIGMET is not issued until the convection has persisted and met the aforementioned criteria for at least 30 minutes. Given that these advisories are routinely issued at 55 minutes past the hour, any convection that has not met the criteria by 25 minutes past the hour may not be included in the routine issuance. Consequently, there are times where a dangerous line or area of developing thunderstorms could be present without the protection of a convective SIGMET. All convective SIGMETs will have a valid time of no more than two hours from the time of issuance.

• READ MORE: Surviving Thunderstorms: Cut Your Risk

Last but not least, these convective SIGMETs are often coordinated by an AWC forecaster with meteorologists at the various Center Weather Service Units (CWSUs) located throughout the country at the various Air Route Traffic Control Centers (ARTCCs). At times, a meteorologist at the CWSUs may issue a Center Weather Advisory (CWA) when building cells are approaching convective SIGMET criteria. The goal is not to duplicate advisories when possible and provide the best guidance for pilots.

The post What Is the Criteria for Issuing a Convective SIGMET? appeared first on FLYING Magazine.

“You’ve been watching, and you still want to go?” the briefer asked.

“Baby needs a wash,” joked the pilot, 66, a recently retired judge who was known for his “well-honed” sense of humor.

“Oh, he’s going to get a wash job,” the briefer said. “We do have a lot of rain and convective activity. It’s becoming pretty solid. I can’t see you doing much dodging trying to get around.”

“It looks like it subsides as it goes east,” the pilot suggested, and then added, “Question mark.”

“Well, yeah, question mark,” said the briefer. “If you take a line drawn directly north, it’s heavy precipitation until you get over to about Bowling Green (Kentucky), and that’s when the thunderstorms start again. But all this is moving northeast about 34 knots, so you head east as it is heading east, and then you get blocked off, and it’s building behind so…you have to go today?”

“Well, maybe not.”

“We will have some rain tomorrow, but at least it will break up enough and begin to move to where, you know, that Arkansas and Missouri area won’t be getting so smashed.”

“I might just go up and take a look at it and see what it looks like out of the windshield,” the pilot mused. “I don’t have anything better to do today.”

“Well,” said the briefer, “think of a good reason to go.”

He issued the required “VFR not recommended” warning—under the circumstances it was hardly necessary—and the pilot filed an IFR flight plan, estimating 2 hours and 15 minutes for the 520 nm trip.

His airplane was a Lancair Legacy, a small, very fast two-seat retractable homebuilt with a 310 hp engine. After climbing VFR to 6,000 feet, the pilot contacted Memphis Approach at 9:50 a.m. The controller asked whether he wanted to continue on his present heading of 356 degrees or deviate eastbound to try to go around the weather. The pilot said he would like to avoid the weather, and the controller gave him a vector of 060. The pilot, however, asked to continue on his present heading for a couple of minutes, and the controller agreed.

A minute later, the pilot came back. “The route ahead, as far as I can see, looks VMC. I can’t be sure on that, but I’d appreciate your input.”

“All right,” the controller replied, “stay on course and let me know if that weather starts to become a problem for you.”

Four minutes later, the controller said, “You are just going to run into about a 10-mile-wide band of showers that’s crossing in front of you. The quickest way through the weather, if you want a direct 90-degree cut, is about a 330 heading. There’s a lot of rain for about 10 miles, and then it should clear up on the other side.”

“All right, thanks,” replied the pilot. “We’ll go to 330, and we’ll slow down a little bit.” Two minutes passed.

“Looks like you are getting an updraft there,” the controller said. “I don’t have any targets around your altitude. Do what you can to hold it, but just take care of yourself through that weather. You’ve got another 10 miles before you’re going to clear it up a little bit.”

“Thank you, sir,” the pilot said.

Twenty seconds later, the controller asked the pilot whether he was OK. There was no reply. The controller’s transmissions became increasingly urgent.

“You’re going through a heavy area of weather, sir. If you can hear me, you, climb, altitude whatever, deviate, reverse course is also approved, sir…Radar contact is lost 30 miles northeast of Memphis, sir…You’ve got another 15 or 20 miles in that weather. If you can hear, sir, suggest a heading northwest bound to get through the weather. You’re in a level 4 and level 5 cell in that area, sir.”

The controller was not long in guessing what had happened. “I think he might have crashed,” he told a colleague.

Three hours later, searchers in a helicopter spotted fragments in a rain-soaked field. The recovery team found the engine and propeller buried almost 9 feet below the surface.

About an hour before the flight took off—but after the pilot’s conversation with the weather briefer—the National Weather Service had issued a SIGMET for the area through which the flight would pass. It warned of severe thunderstorms with tops to 38,000 feet, possible 50-knot gusts and 1-inch hail. The pilot most likely never saw the SIGMET. A retrospective analysis of Doppler weather radar recordings confirmed that at the time of the crash the pilot was just crossing the leading edge of a level 5 storm.

The National Transportation Safety Board limited its finding of “probable cause” to the trivial insight that the pilot had lost control of the airplane. A factor in the accident, it added, was “insufficient information” provided by the controller, who did not convey the storm’s intensity level to the pilot until he was already in it. Exactly how and why the loss of control occurred was not discussed. The wreckage was too badly fragmented for forensic analysis, and significant portions of it were not recovered at all. It did not appear that the airplane had broken up in flight, however. The wreckage was confined to a small area among plowed fields where more widely scattered debris would have been easy to find.

• READ MORE: The Road Not Taken

This accident occurred in 2004. In the intervening years, the NTSB has moved away from mechanistic analyses such as “loss of control” and toward more judgment-oriented ones signaled by the phrase, “the pilot’s decision to…” Today, I think, the finding of probable cause would put more emphasis on decision-making on the parts of both the pilot and controller, although the board’s investigations seldom satisfactorily dissect the nuances of decisions made by two people unconsciously influencing one another. The pilot’s assertion that it looked like VMC ahead probably affected the controller’s interpretation of his own weather display. The controller’s mention of 10 miles of “showers”—two and a half minutes in the Legacy—probably alleviated the pilot’s concern about the storm.

At the risk of venturing into groundless speculation, I am inclined to note that, as a judge, the pilot was accustomed to being the final arbiter of complex questions. As the builder-pilot of a beautiful—the word he used when filling in the “color” field in his flight plan—high performance airplane, he also probably experienced a little of the feeling of untouchable power that comes with fast airplanes and fast cars. The weather briefer hinted, warned, cajoled—but his objections were overruled.

This review first appeared in the July 2023/Issue 939 print edition of FLYING.

The post Objection Overruled appeared first on FLYING Magazine.

My ride that day was a brand-new Piper Archer, N2876K. It was well equipped for that era; it even had a two-axis autopilot and DME—a luxury in those days. The flight was planned for four hours plus, with a stop in Indianapolis for fuel and to check weather at the Combs Gates FBO. I filed my first solo instrument flight plan and departed at 8:30 a.m. local. The weather was VFR all the way to Indianapolis International Airport (KIND)with only early morning haze to contend with. After picking up my IFR flight plan from Cleveland Departure, I climbed with the sun at my back into a cloudless blue sky. I felt like I belonged.

A quick 2 hours and 15 minutes later, I was taxiing up to Combs Gates with a real sense of accomplishment, maybe even more than four days earlier when I passed my checkride. After all, I was flying in the “system” with no supervision—entirely on my own. However, that was about to change. The next segment between Indianapolis and 50 miles east of St. Louis produced one of those life-altering moments for an aviator, one that shaped every aspect of my future flying career.

As I topped off the tanks and had a sip of Coke, I had a pleasant conversation with a flight service specialist who gave me a standard briefing that included: “VFR along the entire route but with a chance of isolated thunderstorms.” Your typical Midwest summer forecast.

Fair weather cumulus started to form, but nothing in the briefing hinted at a go/no-go decision. In fact, the briefer mentioned the cloud bases reported along the route were at least 7,000 feet. Just for safety, I filed for a westbound altitude of 6,000 feet on Victor 14. I wanted to be on an IFR flight plan—just not hard IFR.

I headed west above the haze and leveled at 6,000 feet. As I approached Terre Haute, Indiana, I saw a confusing solid wall of clouds extending many thousands of feet above my altitude. The clouds didn’t look like cumulus. A quick call to Indianapolis Center confused me even more. The controller said he wasn’t “painting” any weather from my position all the way to St. Louis.

At this point, I considered canceling IFR and landing at Terre Haute. But I scrapped that idea. My ego got in the way. After all, I had just passed my check ride in actual, and I was beaming with confidence. Onward I flew into the cloud bank. The initial ride generated an occasional bump at worst. I felt confident I had made the correct decision to continue. I couldn’t have been more wrong.

Soon I was handed off to Kansas City Center over eastern Illinois. By this time, the Archer was jolted by continuous moderate turbulence. My confidence quickly turned into real concern. I keyed the mike and asked the new controller about the weather in front of me, but he only came back with “light to moderate” precipitation for the next 50 miles. At this point, the airplane was still on autopilot and handling the chop and occasional upset.

Then the situation got worse. Torrential rain, continuous lightning, severe turbulence, and—most upsetting to me—the vertical speed indicator was first pegged up to the stops and then pegged in the opposite direction. I reduced power for an indicated airspeed lower than maneuvering speed (V_A), but I knew I was in trouble. I was convinced the wings were going to separate from the airframe. I felt more like a helpless passenger than PIC.

I called Kansas City Center again, but this time I confessed my unfortunate position. I was on the verge of tears. There was little or no controlling my altitude. The updrafts and downdrafts were so strong I knew any attempt to maintain altitude would cause a break up.

• READ MORE: Racing a Storm Is Not the Best Choice

I needed help, quickly. The controller sensed the urgency in my transmission and calmly said, “Stand by.” A few moments later, the controller handed me off to a new one. I was to be his only customer, and he volunteered that he was only “painting” light to moderate precipitation, but I told him the airplane was in severe updrafts and downdrafts. He said to keep the wings level, and he would try to steer me clear of the heaviest precipitation.

Time stood still. I have no recollection of how long he vectored me. He kept saying not to worry about altitude and just try to keep the wings level. The controller continued to “suggest” headings followed by “How’s the ride now?” I wasn’t reassured, but I did robotically turn as suggested, all the time going up and down the elevator. I was soaked through with perspiration and exhausted.

This went on until just south of Litchfield, Illinois, when he cleared me down to the minimum en route altitude (MEA), and I broke out of the cloud bases. Now I had a fighting chance of surviving. There was lightning in all quadrants and sheets of virga I had to dodge, but that was manageable. While the updrafts and downdrafts had subsided, there still was continuous moderate-to-severe turbulence. My head hit the side of the airframe, the headliner, and the glareshield. And without warning, just as I was handed to St. Louis Approach, the airplane broke out into CAVU VFR.

I landed at Spirit of St Louis Airport with the aircraft in one piece—but I was scarred for life. I had been sure I was going to die and would be just another low-time pilot who flew into a thunderstorm. I was so grateful the controller had helped me through, but I knew I would never look at instrument flying the same way. Thousands of hours later, I am still haunted by that flight.

This article first appeared in the July 2023/Issue 939 print edition of FLYING.

The post Humbled for Life appeared first on FLYING Magazine.

By Thursday morning, more than 300 flights had been canceled because of the rising water, according to aviation tracking site FlightAware. Travelers were warned not to try to enter or leave the airport as the roads surrounding it were impassable because of the flooding.

Video posted on social media showed water coming into airport buildings and flooded ramps and taxiways. The roads in and out of the airport as well as parking structures were also flooded, and some were blocked by stalled vehicles.

Airport officials released a statement Thursday morning noting, “We ask for your patience as we wait to safely assess the impacts of this unprecedented rainfall to restore airport operations when it is safe.”

Amazing supercell dynamics involved in this catastrophic flash flooding

Watch as lead supercell sheds a constant chain of occluded circulations which converge over Fort Lauderdale, forming a new (tornadic) supercell. pic.twitter.com/iOx4nuUYK7

— Cameron Nixon (@CameronJNixon) April 13, 2023

According to Airnav.com, the airport sits at an elevation of 65 feet and has two parallel runways, 10L/28R measuring 9,000 x 150 feet, and 10R/28L measuring 8,000 x 150 feet. There are 80 aircraft based at the field, which averages around 759 operations a day and includes commercial carrier operations.

Airnav lists four FBOs on the field: Jetscape, Sheltair, Signature Flight Support  and National Jet. Sheltair, Jetscape and National Jet reported they are closed because the airport was still closed as of noon west coast time, and their employees are either at home or sheltering in place. FLYING was unable to reach Signature Flight Support. 

The airport is served by Spirit Airlines, JetBlue Airways, Southwest Airlines, Delta Airlines, and American Airlines.

FLL will be closed until Friday.

"Please don't come to the airport right now," the mayor of Broward County said on Thursday. https://t.co/jokRoQjL2V

— Frommer's (@Frommers) April 13, 2023

All schools in Broward County have been closed for the duration of the event. According to the National Weather Service, a flood watch was in effect across much of South Florida through Thursday evening, prompting city and county officials to issue a warning to residents to stay off roads unless ordered to evacuate or while seeking safety.

The National Weather Service said more rain was expected to continue throughout Thursday, with possible hail and tornadoes.

The post Flooding at Fort Lauderdale Airport Causes Cancellations appeared first on FLYING Magazine.