View Full Version : Japanese AH-64 crash in Kanzaki, 5/2/2018
treadigraph
5th Feb 2018, 12:15
Appears to have crashed into a residential area with the loss of the crew; hopefully no one on the ground injured:
At least two dead as Japanese military helicopter crashes into residential neighbourhood (http://www.telegraph.co.uk/news/2018/02/05/least-two-dead-japanese-military-helicopter-crashes-residential/)
Sorry, behind paywall.
ethicalconundrum
6th Feb 2018, 02:14
Condolences for all aboard. These planes were built by Fuji ind under license. They came out as advanced block II, but I think they were upgraded to block III not long ago, with composite rotor blades. Way back in the 80s I was stationed at Futenma, we were supposed to have some joint exercises with JDF marines, and air cover but someone further up the food chain nixed it. They don't have a stellar record of safety. However, just as likely the plane let them down at this point.
jolihokistix
6th Feb 2018, 03:41
Viewing the news here it seems it had been in for repairs and was on a final test run. Witnesses heard a rough noise from the rotor and saw parts falling off in the final three seconds as it ‘nose-dived’.
jolihokistix
6th Feb 2018, 03:44
Oops, I should have read this article first!
https://japantoday.com/category/national/SDF-chopper-crashes-in-residential-area-in-Saga
jolihokistix
6th Feb 2018, 06:05
Newly replaced main rotor head detached just prior to crash?
https://japantoday.com/category/national/update1-police-find-body-believed-to-be-pilot's-in-sdf-chopper-crash
ethicalconundrum
6th Feb 2018, 16:12
Well, this is starting to sound distressingly familiar. I doubt we'll ever hear more about the accident chain in the Japanese news, but wondering if the required ground run, and hover tests were completed, with inspection before just taking off for a little spin.
http://www.asahi.com/ajw/articles/AJ201802060049.html (http://www.asahi.com/ajw/articles/AJ201802060049.html)
This video may be of interest. (It does not appear to be behind a paywall).
army_av8r
6th Feb 2018, 22:03
Very similar to the galveston bay accident, and the fort Campbell accident. Main rotor separation in cruise flight.
Very similar to the galveston bay accident, and the fort Campbell accident. Main rotor separation in cruise flight.
Yup. And without chopping the tail. So very likely not preceded by loss of individual blade. Just the Main rotor departing. Chilling and sad.
ethicalconundrum
6th Feb 2018, 22:24
I see at least two blades come off, and that would leave two on the mast/head. More and more like maint issue from the inspection/repairs. Hard to see though, but seems like just before the ground, I can see blades still attached. Maybe...
ethicalconundrum
6th Feb 2018, 22:32
at 0.18 I can clearly see two blades. One at 2, and one at 8 relative to the airframe. At 0.24-25 I think I see main blade rotation just before impact. I don't think the hub departed, but speculation of course.
jolihokistix
7th Feb 2018, 00:33
There was a clear shot on the news of a blade lying across the bottom of a concrete water culvert some distance away.
jolihokistix
7th Feb 2018, 00:48
Here: https://www.jiji.com/jc/article?k=2018020600888&g=soc
and a time-lapse shot here:
https://www.jiji.com/jc/d4?p=sag205&d=d4_ftee
army_av8r
7th Feb 2018, 03:13
Strap pack failure? Without seeing the root of the blade, it's hard to say the cause of the failure. But I think I saw 2 blades depart during the accident video. I wish Boeing would put more effort into this recurring problem.
Crystal Clear 247
7th Feb 2018, 04:02
Hmmm reminds of a Whistling Chicken Leg issue a 20 years ago.
ethicalconundrum
7th Feb 2018, 16:02
Strap pack failure? Without seeing the root of the blade, it's hard to say the cause of the failure. But I think I saw 2 blades depart during the accident video. I wish Boeing would put more effort into this recurring problem.
Since it was coming out of mx, if not a failure of the strap pack, could be incorrect asm after stage check, or left loose, or something like that. A dual failure would indicate that the problem was not related to one blade asm, but covered both blades being affected. It would be possible for the first failure to lead to the second failure, but then the other two blades seemed to stay on the hub all the way down.
Since it was coming out of mx, if not a failure of the strap pack, could be incorrect asm after stage check, or left loose, or something like that. A dual failure would indicate that the problem was not related to one blade asm, but covered both blades being affected. It would be possible for the first failure to lead to the second failure, but then the other two blades seemed to stay on the hub all the way down.
After one comes off for any reason, the rest can be a crap shoot.
tartare
7th Feb 2018, 21:23
Trying to Google it - the strap pack is that series of plates that hold the blade root to the hub... right?
jolihokistix
8th Feb 2018, 00:30
'main rotor head' is what got changed.
https://www.asahi.com/articles/photo/AS20180206001939.html
Trying to Google it - the strap pack is that series of plates that hold the blade root to the hub... right?
Yes. The "straps" carry the centrifugal loads on the pitch housing/blade.
Thomas coupling
8th Feb 2018, 08:30
Wouldn't want to be the engineer who fitted it, nor the chief who signed it off, nor the company who owns the business.
Japs don't take kindly to failure of any sort....
What a dreadful way to go.......RiP guys.
Delta Torque
9th Feb 2018, 01:33
Japanese, Thomas.....Japanese......
jolihokistix
9th Feb 2018, 05:49
Let's hope no-one takes the Happy Despatch. Sad enough already.
Thomas coupling
9th Feb 2018, 11:35
Or is it Nipponese?
Maintenance make errors, just like pilots, after all we're all human. Our operation had an aircraft assigned as the night standby every night for response to any emergency off shore. The aircraft was prepped so all a call out crew had to do was pull the bungs and go. Called out early one morning for a medevac off shore, fired up the night standby and got airborne. Bit of a vertical but completed the 45 minute flight and told maintenance it could do with some tracking upon return. A look found powder coating all four elastomerics at the blade grips. Had had a head build up installed minus all four spindle bearings. Surely the vertical would have been evident during the post install track, or was a track not done, or a test flight?
jolihokistix
14th Feb 2018, 10:02
Reports coming through the main media today that the rotorhead was not new as had been announced but was in fact a used one with 845 hours on it that had been sent back to the US manufacturer in 2011 for refurbishment.
In Japanese, but English translations should be appearing very shortly.
Pic.
https://headlines.yahoo.co.jp/hl?a=20180214-00000075-mai-soci.view-000
Article.
https://headlines.yahoo.co.jp/hl?a=20180214-00000075-mai-soci
Lonewolf_50
14th Feb 2018, 13:45
A lot can happen in 6 or 7 years time ...
jolihokistix
15th Feb 2018, 03:26
More detail in English here:
Used rotor head installed before GSDF copter crashed in Saga?The Asahi Shimbun (http://www.asahi.com/sp/ajw/articles/AJ201802140054.html)
never takes these mass media seriously when it comes to very specific topics like for example this case, aircraft maintenance. What is new, what is old? A TSN 0 part is new, A TSO 0 part is new/old? A part that has no SLL overhaul with TSN 0 SLL component to form a TSO 0 assy is new or old?
jolihokistix
16th Feb 2018, 00:15
Point taken, but sometimes any news is better than silence, so please do not shoot the messenger. Take everything with a pinch/grain of salt, I reckon!
ethicalconundrum
21st Feb 2018, 00:18
More detail in English here:
Used rotor head installed before GSDF copter crashed in Saga?The Asahi Shimbun (http://www.asahi.com/sp/ajw/articles/AJ201802140054.html)
Confirming that two of the blades left in flight as I suspected. What's interesting, is that 'still attached to part of the main rotor asm'. Will be interesting to find out what part of the main rotor asm was still attached to the blades.
According to this, the rotor head was refurbished(?) by Subaru, more than likely in Japan, and I doubt it went to Boeing for work or cert.
army_av8r
21st Feb 2018, 02:44
When a strap pack fails, it will allow the blade grip and all associated hardware to depart with the blade. That unbalance can result in the opposing blade failing as well. Strap packs should be a zero defect part. But many pilots are ok with broken straps. When i say broken straps I'm referring to the individual sheets of metal that make up a strap pack.
A681001
21st Feb 2018, 03:56
Reports coming through the main media today that the rotorhead was not new as had been announced but was in fact a used one with 845 hours on it that had been sent back to the US manufacturer in 2011 for refurbishment.
In Japanese, but English translations should be appearing very shortly.
Pic.
https://headlines.yahoo.co.jp/hl?a=20180214-00000075-mai-soci.view-000
Article.
https://headlines.yahoo.co.jp/hl?a=20180214-00000075-mai-soci
If you go to the very bottom of the pages there is a English button