No fatalities

2023-09-21: Embraer EMB-545 Praetor 500 (N434FX) — Flexjet — Brunswick-Malcolm McKinnon, United States of America

Brunswick-Malcolm McKinnon, United States of AmericaLanding (descent or approach)

On September 21, 2023, an Embraer EMB-545 Praetor 500 (registration N434FX) operated by Flexjet was involved in an aviation accident near Brunswick-Malcolm McKinnon, United States of America during landing or approach. No fatalities were reported. Investigators recorded the probable cause as: The control laws of the angle of attack limiter protection system, which precluded the system from disengaging during an approach in gusting wind conditions, limiting the flight crew's ability to control the airplane's pitch and resulting in a hard landing. This summary draws on records from the Bureau of Aircraft Accidents Archives (B3A); 1 related events involving the same aircraft type or operator are linked below.

Sourcesthe Bureau of Aircraft Accidents Archives (B3A)Primary reportUpdated 1781189173Data APIEditorial standards

On September 21, 2023, a Flexjet Embraer EMB-545 sustained substantial damage after a hard landing at St. Simons Island, Georgia. All eight occupants were uninjured. The NTSB cited the angle of attack limiter's control laws for limiting pitch control in gusting wind.

Accident Overview

On September 21, 2023, at approximately 1436 eastern daylight time, an Embraer SA EMB-545 MOD airplane, registration N434FX, operated by Flexjet LLC as Flexjet flight 434, was substantially damaged during landing near St. Simons Island, Georgia. The flight crew (pilot and copilot) and six passengers were not injured. The flight was conducted under 14 CFR Part 91K (fractional ownership).

Flight Sequence

The airplane departed Westchester County Airport (HPN), White Plains, New York, at 1239, destined for St. Simons Island Airport (SSI). According to the flight crew, the departure and en route phases were uneventful, and all checklists were completed per procedures. The pilot, flying from the left seat, elected to fly the GPS runway 4 approach to allow more time for alignment and setup due to gusting wind. He selected flaps 3 configuration and engaged the autothrottle.

The copilot reported they had the runway in sight from 10 miles out and made a "500-ft stable, 20-kt headwind" callout at 500 ft above ground level (AGL). The NTSB airplane performance study later confirmed that the flight data recorder (FDR) and cockpit voice recorder (CVR) data indicated a stable approach up to that point. The autopilot was disconnected at 1435:49 when the airplane was about 500 ft AGL.

Unusual Pitch Behavior

When the airplane was about 100 to 150 ft AGL, it crossed over a tree line, and the pilot felt an "uplift" followed by porpoising. The pilot attempted pitch corrections using the sidestick but noted the airplane did not respond as commanded. The copilot observed the pilot making what appeared to be "very aggressive" sidestick inputs. The copilot then asked if the pilot wanted him to try, but when he pulled back on his sidestick, it felt like nothing happened. The copilot stated they were "along for the ride" and braced for impact.

The NTSB performance study determined that at about 1436:19 (13 seconds before touchdown), at 162 ft radio altitude, the airplane's angle of attack (AOA) increased suddenly, likely due to a wind gust. The AOA limiter protection system (aerodynamic stall prevention) engaged and reduced the AOA. This system remained engaged until touchdown, limiting the airplane's response to the pilot's pitch commands. Neither crew member indicated awareness that the AOA limiter had engaged.

Impact and Post-Impact

At 1436:28, a terrain awareness and warning system (TAWS) "sink rate" aural alert sounded. During the 3 seconds before touchdown, the pilot commanded full nose-up pitch, but the fly-by-wire system responded with only about 3° nose-up elevator (max range 25° up to 15° down). A horizontal gust reduced indicated airspeed by about 8 knots. During the last 1.5 seconds, the copilot also commanded full nose-up pitch, but the system responded with 5.5° nose-down elevator about 0.5 second before touchdown.

The airplane impacted the ground at 1436:32. The copilot described a hard touchdown before the runway threshold on centerline, followed by a bounce and a second touchdown. The airplane listed and drifted right as it skidded. The copilot noted poor deceleration; the pilot attempted to stop. The copilot pulled the emergency brake handle but felt no effect and returned it. The airplane exited the right side of the runway, struck a concrete sign base, and skidded sideways before coming to rest on grass. After shutdown, all occupants deplaned through the main cabin door.

Probable cause

The control laws of the angle of attack limiter protection system, which precluded the system from disengaging during an approach in gusting wind conditions, limiting the flight crew's ability to control the airplane's pitch and resulting in a hard landing.