Litium battery thermal event Accident Lockwood AirCam N123GN,
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ASN Wikibase Occurrence # 225951
 
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Date:Saturday 8 June 2019
Time:09:38 LT
Type:Silhouette image of generic ACAM model; specific model in this crash may look slightly different    
Lockwood AirCam
Owner/operator:Private
Registration: N123GN
MSN: AC-0248
Year of manufacture:2017
Total airframe hrs:7 hours
Engine model:Rotax 912ULS
Fatalities:Fatalities: 1 / Occupants: 1
Aircraft damage: Substantial
Category:Accident
Location:Hemet-Ryan Airport (HMT/KHMT), Hemet, CA -   United States of America
Phase: Take off
Nature:Test
Departure airport:Hemet-Ryan Field, CA (HMT/KHMT)
Destination airport:Hemet-Ryan Field, CA (HMT/KHMT)
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
Narrative:
The pilot, who was also the owner/builder of the experimental amateur-built kit airplane, was conducting his first test flight in the airplane after having received a special airworthiness certificate 1 week earlier from the Federal Aviation Administration, which allowed him to begin Phase 1 flight testing. On the morning of the accident, several of the pilot's friends and acquaintances gathered to watch his first flight. A video showed that during takeoff, as the airplane reached about 20 ft above ground level, the left wing folded upward. The airplane immediately rolled left and subsequently impacted the ground.
Examination of the airplane revealed that the forward and rear left-wing lift struts remained connected to the wing but were not attached to the fuselage attachment fittings. Further examination revealed that the fittings on the fuselage were intact, and their corresponding bolt holes were undamaged; the bolts were present and secured to the lift struts with washers and nuts but had not been connected to the fuselage through the attachment fittings. The forward and rear right-wing strut were properly attached to the fuselage attachment fittings and the hardware was secure.
Two friends assisted the pilot during the build process. One of them was an airframe and powerplant mechanic, and he reported that the left wing had been removed and reinstalled several times during the build process due to build errors. Each installation required that the attachment hardware be removed and reinstalled, which the pilot performed each time on his own. The mechanic reported that he periodically reminded the pilot to verify that the attachment hardware had been installed correctly, but he continued to find loose screws and nuts throughout the build process.
The pilot likely attempted to install the lift struts on the fuselage after the wing's last reinstallation but failed to ensure that the left-wing lift strut bolts were secured to the fuselage attachment points through the attachment fittings. Although postaccident testing revealed that a correctly installed lift strut was closer to the fuselage along the attachment fitting than an incorrectly installed lift strut, the pilot did not detect the difference between the left and right wings. Postaccident examination of the airframe and engine did not reveal any other mechanical malfunctions or failures that would have precluded normal operation. Therefore, the pilot's failure to properly attach the left wing to the fuselage likely led to its failure shortly after takeoff.
A Federal Aviation Administration designated airworthiness representative (DAR) inspected the airplane 1 week before the accident and issued the pilot a special airworthiness certificate the same day as he was comfortable with the overall assembly. The DAR was not responsible for the final construction and assembly of the airplane as this was the responsibility of the builder.


Probable Cause: The pilot/builder's improper installation of the left wing during the build process, which resulted in the wing failing during takeoff.

Accident investigation:
cover
  
Investigating agency: NTSB
Report number: WPR19FA161
Status: Investigation completed
Duration: 1 year and 11 months
Download report: Final report

Sources:

NTSB WPR19FA161
FAA register: https://registry.faa.gov/aircraftinquiry/NNum_Results.aspx?NNumbertxt=123GN

Location

Images:


Source: NTSB

Media:

Revision history:

Date/timeContributorUpdates
08-Jun-2019 21:28 Captain Adam Added
08-Jun-2019 22:25 RobertMB Updated [Registration, Cn, Source, Narrative]
09-Jun-2019 06:59 harro Updated [Aircraft type]
09-Jun-2019 14:54 Iceman 29 Updated [Time, Source, Embed code, Damage, Narrative]
09-Jun-2019 14:55 Iceman 29 Updated [Embed code, Damage]
09-Jun-2019 15:07 Iceman 29 Updated [Embed code]
10-Jun-2019 21:56 RobertMB Updated [Time, Location, Departure airport, Source, Damage, Narrative]
19-Jun-2019 18:41 Iceman 29 Updated [Destination airport, Source, Narrative, Photo]
19-Jun-2019 18:44 Iceman 29 Updated [Embed code]
02-Apr-2022 16:48 harro Updated [Embed code]
08-Jul-2022 15:47 ASN Update Bot Updated [Time, Other fatalities, Nature, Source, Embed code, Damage, Narrative, Category, Accident report]

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