Major Michelle Curran has gone through the start-up sequence of the F-16 Fighting Falcon thousands of times. She has more than 1,500 hours on the airframe, with 163 of those logged as combat hours during Operation Resolute Support and Operation Freedom’s Sentinel in Afghanistan.
Now, as Thunderbird no. 5, the lead opposing solo pilot of the United States Air Force Air Demonstration Squadron, there’s an additional step involved in the start-up sequence. Before she takes flight, she winds up a mechanical stopwatch that sits in a metal bracket screwed into the left side of the glare shield on her F-16 Fighting Falcon.
Visually, the stopwatch, a Marathon, blends in with the rest of the instrumentation. It sits right above the Radar Warning Receiver and to the left of the HUD (Heads Up Display) in the cockpit. It even looks like it may have rolled off the assembly line at the Lockheed Martin factory that way. But it is, in fact, a modification unique to the Thunderbird solo pilots.
The Thunderbirds flight demonstration team is made up of six pilots, most with combat experience, who specialize in a number of different types of flying. All six pilots are highly skilled at flying in tight, graceful formations. When flying in the standard “delta formation,” they’re less than three feet apart from each other. During a standard demonstration routine, two pilots will break off from the formation, leaving the other four aircraft in a “diamond formation.” Those two pilots are the designated “solo pilots,” and Maj. Curran is the lead solo pilot.
I had the opportunity to speak to Maj. Curran last week about the mission-critical timekeeping methods that allow Thunderbird pilots to execute their routine safely and with incredible precision. In a typical show, the solo pilots travel at 450 knots (that’s a ground speed of 517 mph) roughly 200 feet above the ground; of course, fractions of a second can make all the difference. And Maj. Curran relies on a humble mechanical stopwatch, based on technology that essentially dates to 1755, when Thomas Mudge introduced the lever escapement to the world. Along with the most advanced flight systems and cutting edge materials, an anachronistic technology plays just as important of a role in executing a demonstration flight.
The Thunderbirds debuted in 1953, and their mission has remained the same since the team’s inception: To Recruit, Retain, and Inspire. Pilots must have at least 750 hours of jet time before being able to apply for the role of Thunderbird pilot, as it’s one of the most coveted positions a rated aviator in the USAF can assume. Before joining the team, Maj. Curran spent three years on an assignment flying the F-16 out of Misawa, Japan, and another three years as an instructor pilot out of Ft. Worth. She’s the first-ever female to fly the lead solo position. Being a Thunderbird pilot is typically a two-year assignment, but due to COVID-19, it’s being extended a year. The Thunderbirds participated in Operation America Strong: On April 28, the Navy’s flight demonstration team, The Blue Angels, together with the Thunderbirds, performed flyovers in NY, NJ, and PA meant to champion national unity behind frontline responders. Maj. Curran told me the America Strong flyover isn’t likely to happen again, saying “the FAA was on board, and the city was on board, and air traffic was light in what’s usually one of the busiest areas in the country. Normally there are a ton of restrictions.”
Their show season has been cut short this year, but it officially starts tomorrow in Ocean City, Maryland. The team has spent the time they’ve been grounded examining their routine and making it better. Lt. Col. John D. Caldwell, the commander of the Thunderbirds and Thunderbird pilot no. 1, has led an effort to examine the routine and understand how it’s changed over the years by analyzing the routines from the ’90s until today. Should it follow the pattern of a firework show with a grand finale? Should it slowly escalate in its intensity? The pilots seemingly fly with such ease, but there’s a great deal of psychology involved with planning a routine. The Thunderbirds are historically known for flying with grace in perfect synchronization; just have a look at this footage from 1965 of an earlier airframe the Thunderbirds operated, the F-100 Super Sabre. This perfect poise is demonstrated in today’s routine, but there’s a certain measure of raw, fast, loud, and brutish flying that spotlights the nature of the F-16.
The unique capabilities of the F-16 snap into focus during the solo demonstration passes. The first maneuver performed is typically the knife-edge pass, and this is where mechanical timekeeping comes into play. Maj Curran explained, in detail, how she uses the stopwatch to pull off this maneuver.
A day before the show, Maj. Curran and Captain Kyle S. Oliver, the opposing solo pilot, will survey the show area and decide on “hack points” based on a predetermined “show center,” a point that’s right in the middle of the viewing area. In the desert around Nellis Air Force Base where the Thunderbirds practice, a simulated show center is marked by a shipping container painted bright orange. The hack points are recorded as GPS coordinates, but visual references are primarily used. Maj. Curran explains that sometimes it can be a house, sometimes a field, or even a building. The hack points are four miles from the show center, and they’re mirrored, one hack point on each side. The pass will involve the F-16s entering the show area from opposing directions and flying straight towards each other at 450 knots, both descending from 2000 ft. to 200 ft. to meet on a line flying directly towards each other.
Once the solo pilots break off from the formation, Maj. Curran gets on the radio and declares “Solos, point at your hacks!”
The F-16s start to turn towards the reference points they decided on the day before.
Next, a pilot from the diamond formation will call out that they’re in position for the solo pilots to start their pass routine.
The solo pilots are quickly approaching their hack point, and Maj. Curran will call out on the radio, “standby hack, let’s hack now” as both pilots are about to reach their hack points. In the jet, both solo pilots will repeat “let’s hack now” and they’ll engage the stopwatch on “now,” starting a 30-second synchronized timer.
When Maj. Curran learned that I was interested in the timekeeping aspect of the Thunderbirds routine, she reached out to a Thunderbird solo pilot who had performed during the ’90 and ’91 seasons. That pilot told her that they did the exact same thing with the exact same stopwatches. So this practice has been used for at least thirty years. That former Thunderbird reached out to the oldest living Thunderbird pilot, Major General Gerald D. Larson, to find out how solo passes were performed in the early days when the Thunderbirds were flying the F-100C. General Larson said they had visual references measured out from show center and would use the radio to sync up in 1965, but no stopwatches were used.
The funny thing is that the stopwatch hasn’t changed much since 1965 (or much earlier, for that matter), the only difference is that as early as the ’90s, the Thunderbirds chose to use it. Maj. Curran says, “It runs like a champ. I don’t think they’ve replaced any since I’ve been on the team.” She’s on her second year with the Thunderbirds. During a standard routine, the load on the stopwatch (and pilot) reaches 9Gs multiple times. That’s a tremendous amount of force to be subjected to on a semi-daily basis, but it’s been working for the past thirty years, and if it’s not broken, there’s no need to fix it.
At the very point that the pilots hack their stopwatch, they should each be four miles from show center, traveling 450 knots ground speed – jets can display indicated airspeed, ground speed, and true airspeed, but for a maneuver like this, ground speed is used because there are a number of variables that can affect timing at this altitude, like winds. One pilot will face a headwind that will mean a tailwind for the other, and that could mean they don’t cross at exactly show center and the pattern is thrown off. Solo pilots constantly perform a “sweep,” scanning multiple instruments in the cockpit, of which the stopwatch is one. Maj. Curran reports that she appreciates the legibility of an analog clock in the cockpit. Watching the sweeping seconds hand has become a standard part of her flight routine.
When the timer reaches 15 seconds, both pilots should be 3.7 miles from show center.
At 20 seconds, 3.2 miles.
At 25 seconds, 2.6 miles.
Finally, at 30 seconds, they’re each 2 miles from show center closing in on each other at a collective 900 knots ground speed. Maj. Curran calls out the maneuver, “Knife Edge!” to which Capt. Oliver in the no. 6 plane will reply ‘Knife Edge!”
At this point, there is no more cross-checking the stopwatch against the range display in the cockpit or the GPS. It’s all visual now. Both pilots might modulate the throttle or apply the speed brakes to maintain the perfect approach.
Right when it looks like the two F-16s will make contact with each other, the pilots roll into a position perfectly perpendicular to the ground so the underside of the plane faces each other. This is where the name of the “knife edge” maneuver comes from. Thanks to some expert piloting and a reliable stopwatch, the maneuver goes off without a hitch.
It’s important to note that every maneuver is graded, and every time a jet makes a pass, every metric is analyzed. If a jet is off by a few hundred feet, the pilot will hear about it during debriefing. Precision is key, and that’s why the stopwatch is so important.
Of course, I had to ask Maj. Curran what she wears in the cockpit. I was secretly hoping it was a Rolex Datejust Turn-O-Graph, specifically one produced in the ’50s decorated with the Thunderbird insignia, a depiction of a mythical creature from the lore of indigenous peoples. But the Thunderbirds of today are solely focused on functionality as opposed to collectible Rolex references. Maj. Curran said she was issued a Garmin fenix watch because it acts as an alarm in the event that cockpit pressure fluctuates beyond nominal parameters, which could lead to full cockpit depressurization. Usually, the cockpit pressure is kept at 8,000 ft., but if it changes drastically, the watch will vibrate.
After her assignment with the Thunderbirds is up, Maj. Curran will go back to flying combat missions. “The transition back to tactical flying vs. demonstration flying isn’t always easy,” she says.
But I bet she’ll make it look easy.