Dassault DA-900B N523AC

Summary

On 9 October 1999 at about 19:10 local time, a Dassault DA-900B registered N523AC was involved in an accident near Holland, Michigan, United States. 5 people were on board and one was seriously injured. The aircraft was slightly damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

9 October 1999 at 19:10

Classification

Accident

Location

Holland, Michigan, United States

Coordinates

42.7703, -86.1002

Aircraft

Dassault DA-900B

Registration

N523AC

Category

Airplane

Engines

3

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Executive/Corporate

Phase of flight

Not recorded

Route

Portland → Grand Rapids

Aircraft damage

Minor

Weather

VMC

Light

Day

NTSB number

CHI00FA006

1 person was seriously injured.

The copilot's improper use of the autopilot system while leveling the flight from descent, resulting in an inadvertent pilot-induced pitch oscillation of the airplane. A factor was the flight attendant not wearing a seat belt at the time of the occurrence.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

The flight experienced a series of pitch oscillations while on descent to an assigned altitude of 11,000 feet mean sea level(msl). The flight attendant was seriously injured. The Captain reported that when he was at about 11,400 feet msl, it appeared the airplane was going to descend below the assigned altitude. The First Officer, who was the flying pilot in the left seat, reported that he pulled back on the airplane's yoke to initiate the level off without disengaging the autopilot. He reported that when he relaxed the back pressure on the yoke, the airplane pitched nose down violently and a series of three to four pitch oscillations occurred before the airplane was brought under control. The aircraft load factors reached magnitudes between +3.3g and -1.2 g. The flight attendant was not wearing a seat belt at the time of the incident. The inspection of the airplane revealed no pre-existing anomalies. Neither the autopilot's pilot manual nor the airplane's flight manual contained a Warning, Caution, or Note that explicitly stated not to manually override the autopilot. On October 18, 1999, Falcon Aviation issued Newsflash 52 that notified operators not to manually apply control yoke forces in an attempt to control the aircraft when the autopilot is engaged.

Quoted verbatim from the NTSB record.