Zenith ZODIAC CH601XL N601KS

Summary

On 23 November 2021 at about 18:33 local time, a Zenith ZODIAC CH601XL registered N601KS was involved in an accident near Temecula, California, United States. One person was on board and one died. The aircraft was destroyed. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

23 November 2021 at 18:33

Classification

Accident

Location

Temecula, California, United States

Nearest airport

French Valley (F70)

Coordinates

33.5490, -117.0921

Aircraft

Zenith ZODIAC CH601XL

Registration

N601KS

Category

Airplane

Year built

2007

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Temecula → Unknown

Aircraft damage

Destroyed

Weather

VMC

Light

Day

NTSB number

WPR22FA048

1 person died.

The failure of the airplane’s canopy latch system, which resulted in the canopy opening in flight and a loss of airplane control. Contributing to the accident was the lack of a secondary canopy latch as recommended by the kit manufacturer.

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

Read the full NTSB narrative

About seven minutes after departure, following what appeared to be an uneventful takeoff and initial climb, the airplane began a 180° turn toward the departure airport. A few minutes later, witnesses heard a loud bang, and the airplane pitched down aggressively, rolled inverted, and impacted the ground in a steep, nose-down attitude. During the descent, the pilot’s flight bag and other cabin contents fell out of the airplane, and the sound of buffeting wind noise and the pilot struggling were heard on the airport’s common traffic advisory frequency. Examination did not reveal any anomalies with the flight controls or engine that would have precluded normal operation, and all components from the airplane were found in the immediate vicinity of the impact site. There was no evidence of bird strike. The owner/builder of the airplane stated that he had once experienced the canopy opening on takeoff but was able to land safely. As a result of this event, he disabled the standard lock and installed a set of two small over-center latches, each mounted to the rear sides of the canopy frame with two soft aluminum rivets. Examination of the canopy system revealed damage signatures that appeared to indicate that the rivets of one latch had separated in shear, and the other latch had twisted away from the airframe. It is likely that the accident was initiated by the failure of the mounting rivets in one latch, which caused the canopy to partially open on one side, then twist the latch away from the other side, resulting in an open and possibly deformed canopy. The reason for the initial failure could not be determined; however, the owner of the airplane was shorter than the pilot and had raised the seat and moved it forward during construction. The modification would have resulted in the accident pilot having to lean inboard, or sit with his head tilted, to avoid touching the canopy. It is possible that the airplane encountered turbulence that caused the pilot to hit the canopy, resulting in the failure of one of the latches. Multiple instances of canopies opening in flight were reported for this airplane model. Because an open canopy disturbs airflow over the horizontal stabilizer, flight control difficulties can result in a loss of control nose-down pitching motion, often accompanied by a loud banging sound and cabin contents being sucked out, all which were observed in this accident. Although the Pilot Operating Handbook (POH) provides instructions for continued flight with an open canopy, evidence from both this and previous accidents suggests that both the nose-down motion and associated negative G-forces can be hard for pilots to maintain airplane control. The airplane’s POH suggested the installation of a secondary backup latch system, and 2 weeks following the accident, the manufacturer issued a safety alert recommending such. The accident airplane was not equipped with a secondary latch.

Quoted verbatim from the NTSB record.