Note, 3 November 2026

The Learjet dive in its own data, and the field that ran out of numbers

On 1 November 2026 a Learjet 60 flying from Austin, Texas, to North Eleuthera in the Bahamas went down in Palm Beach County, Florida. All nine people aboard died; our sympathy goes to their families and friends. The jet's own broadcasts record the dive closely: it fell five miles in about a minute, fast enough that one field in its data ran out of numbers. The cause is not known; the NTSB is investigating.

What happened

The jet left Austin on Sunday morning with two pilots and seven passengers. It cruised at 41,000 feet and, near Naples, Florida, started down to 35,000 (Flightradar24). CNN reports it passed through a stronger storm cell a few minutes before the dive; the NTSB has not yet confirmed whether it flew through an active thunderstorm (WFLX).

At 12:47 p.m. Eastern the crew told Miami Center they had light, clear ice that was manageable, and moderate turbulence (WFLX). At 12:48:28 they declared a Mayday, descending 10,000 feet a minute, and seconds later reported an overspeed, at 20,000 feet a minute (CNN, from air traffic control audio). At its 2 November briefing the NTSB said "we do have some evidence that there was some breakup of the aircraft before impact. We're still seeking to determine that" (CNN), and called weather "a major focus" (WFLX).

What the data shows

The numbers are the jet's ADS-B broadcasts, published by adsb.lol under the ODbL, in Florida time.

From 12:47:50 the pressure altitude rose for about 25 seconds, by 475 feet, to 35,450 at 12:48:15; CNN's timeline puts the crew's request to climb to 37,000 feet at 12:48:00. Then it started down. Fourteen seconds later it was descending 10,000 feet a minute; nine seconds after that, 20,000. Its ground speed peaked at 507 knots as it turned right, from east through south to west-northwest. From 35,250 feet to 8,750 feet took about a minute: 26,500 feet, five miles.

Why the field ran out of numbers

ADS-B sends vertical rate as a 9-bit number in steps of 64 feet a minute, with a separate bit for up or down (The 1090 MHz Riddle; RTCA DO-260B, ICAO Doc 9871). The top code carries no number. It only means faster than 32,608 feet a minute, and decoders print it as 32,640.

From 12:49:05 to the last point, 27 seconds, the jet's field sat on that code. Over the same stretch its GPS height fell at about 49,000 feet a minute on average, half again past the top of the scale.

Where the data stops

At 12:49:23 the pressure altitude stopped updating, at 8,750 feet. The GPS height kept falling; the last point, at 12:49:32, gives 325 feet, measured from the WGS-84 ellipsoid, not the ground. The data does not say why the pressure altitude stopped.

What is not known

Why. The NTSB has named no cause. At its briefing it said it would not establish a probable cause at the scene, "nor will we speculate about the cause" (UPI). A preliminary report is expected within 30 days of the crash (CNN), and the NTSB tries to finish an investigation within 12 to 24 months (NTSB). This note is current to 3 November 2026.

Our take

Every fixed-width field has a top. This one is sized far beyond normal flight and still ran out. The standard already gives its top code a meaning, above range; the tools that decode it print a number. When we design telemetry, we keep that state a state all the way to the screen, and keep a second, independent measure beside it. Here the GPS height did that job. This is about data design, not about the cause of this accident.

About the films

Our Part 1 follows the script of Ceramico's Part 1, with two timings corrected; the data has since superseded its ten-second climb and its nose drop. Part 2 and the animation are ours. The jet is drawn from Bombardier's three-view, without registration or livery. Path, altitudes and speeds are the ADS-B data; the storms are drawn where NOAA's NEXRAD composites showed them (Iowa Environmental Mesonet); that radar does not show conditions at the jet's altitude. The film's strong-cell line is CNN's report; the NTSB cannot yet confirm it. The map is Natural Earth. The ice on the wing illustrates the crew's report. Nothing shows the impact or anyone aboard. Part 3, on what investigators are checking, has its own note.

Transcript

This jet fell so fast, its own transponder ran out of numbers. Part two: the dive, in the data.

At thirty-five thousand feet it climbs for twenty-five seconds. Then it starts down. Fourteen seconds later, it's falling ten thousand feet a minute. Nine seconds more, twenty thousand. It peaks at five hundred and seven knots over the ground, and turns right as it falls.

Then the vertical speed hits the top of its scale. That field is nine bits. Its last code only means: faster than thirty-two thousand six hundred and eight feet a minute. It sits there for the last twenty-seven seconds. The GPS height says forty-nine thousand a minute.

At eight thousand seven hundred and fifty feet, the pressure altitude stops updating. The GPS height keeps falling, to three hundred and twenty-five. The data shows how fast. Why is for the NTSB.

All notes