With 3 occupants (a pilot and two passengers) a Cessna 421B Golden Eagle (built in 1974) was taxiing out to the 5000-foot-long runway at Franklin-Macon County Airport (North Carolina, USA) for a private flight (FAA Part 91), on the 11th of March 2021.
The aircraft wreckage after the post-crash fire was extinguished (Source; baaa.acro.com © Franklin Fire & Rescue)
The engine start and the taxi to the runway were uneventful, as was the run-up before take-off. After receiving take-off clearance the throttles were brought forward. As the aircraft accelerated down the runway the pilot called out the airspeed every 10 knots.
The rotation speed for the conditions and the aircraft weight this day had been determined to be 100 knots. At about 90 knots the pilot noticed a lag in the acceleration of the aircraft. The maximum speed the aircraft reached was 92 knots. With about 1500 feet of runway remaining the pilot aborted the take-off by pulling back the throttles and applying maximum braking. However, there appeared to be no deceleration, the aircraft left the paved area of the runway, roughly on the runway heading, continued down a slope, and through a fence before coming to rest. A fire broke out, but all three occupants managed to evacuate the aircraft without injuries.
A check of the runway by an FAA inspector revealed tyre skid marks starting 1200 feet before the end of the runway, and continuing up to the final position of the aircraft, the brakes had worked apparently.
The aircraft wreckage after the post-crash fire was extinguished (Source; baaa.acro.com © Franklin Fire & Rescue)
The aircraft wreckage was examined by an NTSB investigator, finding the cockpit and cabin destroyed by fire. Flight instruments and aircraft controls were burned to such a degree that their indication and/or position could not be determined. Examination of the left and right engines revealed that both were heavily fire-damaged but that the engine cases remained intact and were not breached. Power and
valvetrain continuity could not be established due to impact and fire damage. The accessories on both engines were also fire-damaged. Both propeller assemblies remained attached to the propeller hubs on both engines but exhibited fire and impact-related damage.
The last flames being extinguihsed (Source; baaa.acro.com © Franklin Fire & Rescue)
In their report the NTSB stated;
Although the tyre marks on the runway indicated that some braking action
took place, the extensive fire damage precluded a detailed examination of the braking system, and there was insufficient evidence to determine the reason for the runway excursion. Concluding that the probable cause(s) of this accident could not be determined based on the available information.
No explanation was given in the report for the lack of acceleration reported by the pilot. The NTSB report which was the source for this blog can be accessed by clicking on the .pdf file below;