News & commentary about aerial firefighting, air tankers, and helicopters
A UH-1H that crashed earlier this year in Tasmania had a fragmented drive shaft
The Australian Transport Safety Bureau (ATSB) has issued a Safety Advisory Notice related to the fatal crash of a Garlick Helicopters UH-1H that was assisting firefighters on February 14, 2022 southeast of Pipers Brook, Tasmania. Andrew Kerr, the only person on board, was killed.
The helicopter was working with an external water bucket when witnesses both on the ground and within a nearby helicopter observed the early release of the water load from the bucket, before the UH-1H commenced a left turn and descended toward nearby open terrain. The helicopter was then observed to slow and enter a hover, then rapidly yaw, before descending and impacting terrain. The pilot was fatally injured and the helicopter was destroyed.
A local resident, Michael McKenna was working in his shed when the incident happened.
“I heard this big bang, something wasn’t right,” he said. “I got to the corner of the house and I saw the helicopter go down.”
The ATSB’s on-site examination of the wreckage found anomalies with the helicopter’s main drive shaft, identified as a KAflex and manufactured in the United States by Kamatics Corporation (Kamatics), that transmits engine power to the transmission. The shaft was found to have fragmented during the accident sequence, with four of the flex-frame attaching hardware (nuts, bolts, and their washers) and portions of the flexible frame elements unable to be accounted at the accident site. The ATSB subsequently commenced a detailed technical examination of the KAflex shaft assembly and importantly, severe frictional and wear damage was identified to have occurred to one portion of the shaft. The results of that work was presented to Kamatics and the Civil Aviation Safety Authority (CASA).
The ATSB issued a Safety Advisory Notice June 15, 2022 advising operators of UH-1H helicopters to note the preliminary details of this accident, the content of AD 2021-26-16 and CASA Airworthiness Bulletin AWB 63-004, and to look for the presence of, corrosion, fretting, frame cracking, missing or damaged flex-frame attaching hardware during all inspections of the KAflex drive shaft. Any identified defects should be reported to the Civil Aviation Safety Authority and the ATSB.
FAA earlier pointed out issues with UH-1H drive shafts
On January 20, 2022 a few weeks before the crash in Australia, the U.S. Federal Aviation Administration issued an airworthiness directive (AD) requiring inspection or replacement of the main driveshaft in certain type certificated Model UH-1H restricted category helicopters that have KAflex main driveshaft part number (P/N) SKCP2180-1, SKCP2281-1, SKCP2281-1R, or SKCP2281-103 installed.
The AD requires establishing a limit to replace the driveshafts, and one-time and repetitive inspections. If the main driveshaft has accumulated 5,000 or more total hours in service (TIS), before further flight it must be replaced or overhauled.
The AD referenced two in-flight failures of the driveshaft that occurred during logging operations in 1997 and 2015.
The FAA estimated the cost of replacing the driveshaft is $54,000 if new, or $38,000 for one that has been overhauled.
Thanks and a tip of the hat go out to Gerald.
Typos, let us know HERE. And, please keep in mind our commenting ground rules before you post a comment.
For us Army and civilian 205 mechanics this was well, as common as inspecting one Pulaskis or engines
I lil inspection criteria fer ya:
https://www.kaman.com/wp-content/uploads/2022/01/ICA3303%20-%20REV%20B.pdf
Cal Fire, Washington DNR and likley some other agencies use Cobra Kflex shafts which are a slightly different design, a bit more meaty, than the UH-1h models. I suspect the restricted category helicopters used by all civil operators can’t use that shaft. I don’t believe there have been any failures in that configuration and although they were 1500 hour items in the AH1, they are run for 5k hours in the Hueys. Different part number.
Your email address will not be published. Required fields are marked *
Notify me of follow-up comments by email.
Notify me of new posts by email.
Have a fire aviation news tip? Click here
Enter your email address to subscribe and receive notifications of new posts by email. There is no cost, and in case you change your mind each email has an unsubscribe button.