R44 Missing North of Montreal

[albatross]

Just found out about the server being down.
When I see it is back up I will post the news here.

[Senior Pilot]

Originally Posted by albatross

Just found out about the server being down.
When I see it is back up I will post the news here.

Another reason why we ask PPRuNers to cut and paste rather than the lazy option of posting a URL

[jeepjeep]

Oh, that's a Canadian web site. It's early April so they have to periodically stoke the server to keep things warm enough to run.

[SpyPilot]

We resent...excuse me please...resemble that remark.

[albatross]

Site is back up.
https://tsb.gc.ca/eng/rapports-repor.../a19q0109.html

Sorry but the report is very long and I couldn’t cut and paste.
Also I was unaware of the “rule”.

[jimjim1]

Originally Posted by albatross

Sorry but the report is very long and I couldn’t cut and paste.

Here is the report file uploaded to pprune. Not sure how it will present but here goes.

Edit - clicking on link downloads the file.

[Arnie Madsen]

The really really short version:

R44 ... outboard section of one blade delaminated and failed
Settled almost straight down through forest canopy ... evidence of low rotor rpm
Pilot found in his seat
Passenger about 200 feet away ... indicates initial survival
ELT was disarmed preventing early rescue.
Robinson's tap the blade musical not performed very often


HTML link

Air transportation safety investigation report A19Q0109 - Transportation Safety Board of Canada (tsb.gc.ca)

[[email protected]]

Has anyone sued Robinson for failing to make airworthy blades that last their service life?

Did Robinson replace faulty blades free of charge?

[gulliBell]

The new blade left the factory with an adhesive bond failure which progressed over time but was not detected by routine maintenance even though these blades were known to be prone to this fault. Quite incredible.

[Hot and Hi]

Originally Posted by [email protected]

Has anyone sued Robinson for failing to make airworthy blades that last their service life?

Did Robinson replace faulty blades free of charge?

For many years, RHC gave a 50% discount in an attempt to accelerate the upgrade to the current dash-7 blades. If I remember correctly, a similar discount scheme was offered to incentivise operators to upgrade to bladder tanks before bladder tanks became mandatory.

[Hot and Hi]

Thanks JimJim for uploading the report, and to Arnie's for their good summary. A few points that come to mind, in no particular order:

• The entire 40-page report is well worth the read.
• Fly the aircraft to the site of the accident. The mishap pilot had time to kill the engine (in an attempt to 'diagnose' the excessive vibration problem) but lost RRPM in the process. Thereby was unable to even attempt an autorotation. So basically crashed with zero engine and zero rotor RPM.
• Despite a similar high profile accident in the same area just three month ago where due to nil flight following or sat tracker (compounded by the usual ELT failure) it took seven days to locate the aircraft, this occurrence flight took off without flight following, no sat tracker and faulty ELT.
• The pilot's medical had expired over a year before the accident (indicates attitudinal problems). Technically speaking, the pilot was not licensed.
• Given the known design problems of earlier RHC blade, the a/c was still equipped with dash-2 blades (current blades are dash-7).
• Blade delamination would have been visible before the accident flight and was big enough that it should have been detected by the pilot, had the mandatory daily visual inspection been carried out. The report found that that the pilot - despite knowing that they flew with old to-be-phased-out blades - didn't conduct this mandatory daily inspection.
• Because the daily visual inspections were not done or recorded, the aircraft's airworthiness certificate was invalidated (indicates attitudinal attitude problem No 2).
• The ELT Arm switch (at the ELT unit itself, not the remote test/activation switch in the cockpit), was found to be damaged. To prevent inadvertent change of that (typically rather inaccessible) switch, this switch has a locking mechanism. In order to move the switch, the switch normally has to be moved up (pulled out) to set it to another position. This also prevents the switch to move to the OFF position by the decelerating forces during a crash. Some ham-fisted person may have just forced the switch thereby breaking the locking mechanism. Since then the ELT Arm switch was free to move between its positions. A CT scan of the broken switch proved that it was moved several times between the OFF and the ARM position over time, after the locking mechanism had been broken. The broken switch problem was not detected or repaired during the periodic ELT maintenance. It was found that in its current state, the broken switch could be moved from the ARM to the OFF position by an acceleration force of just 1.8G (which is below the activation force that should activate the ELT's the G-switch - around 6G - and well below the over 16G forces that occurred during this crash).
• The (initially) surviving pax activated the ELT with the remote switch in the cabin. But because the ELT was switched off at the unit itself, it didn't work. Anyway, we know that ELTs fail (for this or other reasons) in 2 out of 3 accidents.
• The report describes over many pages how the lack of good crash position estimates can frustrate the SAR efforts, but fails to mention that carrying a (monitored) sat tracker would therefore be recommended.

[aa777888]

H&H has it right. 50% discount program. Don't remember the terms of the deal. While I did suffer through the same issues on my R44, I came late to that particular party and ran the -5's until the AD deadline. That worked out pretty well for me as it brought me the ship at a substantial discount and the timing was pretty good, with the blades calendaring out only 4 months after the replacement deadline, so I gained far more than I lost. I didn't mind doing the daily inspection or the record keeping that went along with it, and we tap tested per the US AD. Had to touch up the blade paint once as it was getting close to the bond line but that was no big deal either.

Unfortunately it is impossible to know if the owner was doing the proper inspections and easy to assume he was not. It is also impossible to know whether they would have made any difference, i.e. would the blade have passed the daily visual inspection anyway?

What is strange about this one is why was there a loss of rotor RPM? It was probably vibrating like crazy but apparently it wasn't flinging bits off (yet). Why was rotor RPM not maintained and an immediate landing accomplished? That's the real mystery. Or did I read the report wrong?

[kansarasc]

What about this ?
https://www.sportys.com/acr-resqlink...E&gclsrc=aw.ds
I heard mixed reviews about reliability of this device

[JohnDixson]

While speculating about why the engine might have been purposely shut down,.....or not, I re-read the report, looking for the calculated cockpit vibration levels, following the loss of the outer B blade at station 161. The report does not have any calculation of that estimated value. Was the ship 1P vibration ( both vertical and lateral ) such that the pilot inadvertently did that while intending something else? Was the environment such that the pilot was rendered virtually unable to do anything of consequence? I’d guess that the Robinson engineering folks did that calculation soon after notification.
The other aspect that occurred to me just after posting this a minute ago was that with large 1P levels, it is altogether possible for the pilot to aggravate the levels-a pilot induced ocscillation ( PIO ) on top of the unbalance caused disturbance. That sort of thing is dependent on a number of factors, but if the basic disturbance is below 6 hz, pilots can respond so as to increase the severity. Preventative measures to prevent PIO is a whole other subject and probably not relevant here.

After awhile, something eslse occurred to me regarding the pilots action in that vibration environment: was the pilot being bounced around so that he couldn’t read the Nr indictor if he wanted to.
I have a data point here. During the development of the UH-60 ( well before the fly-off part of the competition ) we were have vibration problems that were challenging our ability to get them ( there were variously caused issues ) resolved. In desperation ( true story ) we took set of S-61 blades, cut them down, modified the grips to fit the elastomeric head, balanced them on the whirl stand and flew them. Well, not so good: the speed maxed out at 137KIAS and the vibration levels were roughly the same. Then someone suggested, that to get a real baseline with the 61 blades, we should take all of the vibration fixes then on the prototype off the machine and fly it bare. I think at the time we had the stacked 3P and 5P bifilars, nose absorber, cabin absorber, and 50 lb fixed absorbers under each pilot seat, mounted on structure. All of that came off. How fast did we go? 20 kts paced forward speed, and the reason for stopping was that the vibration levels ( N/rev or 4P ) were such that the instrument panel disappeared in a blur-nothing was readable. Turns out we were done for quite a separate reason as well-we had blown by all of the GE T-700 engine vibration do not exceed limits.

[gulliBell]

Originally Posted by aa777888

i.e. would the blade have passed the daily visual inspection anyway?

The report discussed this. The delaminated skin would have been visible on pre-flight inspection.

[[email protected]]

I have had a chunk of blade tape bubble and cause horrendous vibration until it finally came off - I have also had a whole blade pocket detach from the spar, again nasty vibration and lots of noise - both occurred about 2/3 of the way to the tip but scary as hell.

What levels of drag and vibration on a 2-blade system and a delamination at the tip would be, one can only surmise but that extra drag would have decreased the Nr even if he had kept the engine going - without it running, perhaps because he panicked and assumed he had an engine problem, he had no chance of retaining Nr.

[aa777888]

Originally Posted by gulliBell

The report discussed this. The delaminated skin would have been visible on pre-flight inspection.

Upon re-reading is see the section you are referring to. It's a shame the owner did not properly inspect his MRBs, then.

Not that it should need to, but owning -5 blades definitely has reinforced a desire to be meticulous about preflight inspections. When you are vertically challenged such as I you can't visualize the top of the blades when on the built in steps you use to check the main rotor head. You need a 10ft (3M) stepladder to do it right, which I have, and do.

[aa777888]

Originally Posted by [email protected]

What levels of drag and vibration on a 2-blade system and a delamination at the tip would be, one can only surmise but that extra drag would have decreased the Nr even if he had kept the engine going - without it running, perhaps because he panicked and assumed he had an engine problem, he had no chance of retaining Nr.

Good point. Vibe levels were undoubtedly dramatic. I had a mag go bad in a way that shifted the timing. That was dramatic enough, but I never thought about securing the engine while it was still making power.

[aa777888]

Originally Posted by kansarasc

What about this ?
https://www.sportys.com/acr-resqlink-view-personal-locator-beacon.html?mrkgadid=1000000&mrkgen=27
I heard mixed reviews about reliability of this device

PLBs are an excellent rescue item and highly recommended. They operate in an identical fashion to an ELT (or an EPIRB) except that they are manually triggered. They are very reliable assuming you are in good enough shape to trigger them. Indeed, assuming they are on your person at the time, they are more likely to survive a crash than an ELT is. And any new PLB is going to have a built-in GPS receiver which will encode your exact position onto the 406MHz ELT signal. Most of the GA ELTs don't have this feature. I carry a PLB myself for all of these reasons and more. That's in addition to the 406 (non-GPS) ELT installed in my helicopter. Honestly, I should really move up to a satellite messenger like the Garmin inReach. It can perform all of the same functions as a top end, GPS-enabled PLB as well as provide 2-way satellite text messaging.

It's worth noting that this ELT failed because of, again, poor maintenance on the part of the MRO and the owner. Because of the broken lugs on the switch, broken prior to the crash per the report, it was unserviceable. Also, contrary to what the report says, if you look at the photo carefully you will see the outer jacket and shield of the coaxial cable have been pulled out of the antenna connector. The performance of the ELT would have been significantly degraded at the very least under those conditions.

I just recently went through the battery replacement cycle on my Kannad 406-AF ELT. The cost of having this done is a joke given that it's 10 minutes of shop time and about $50 worth of material. With the cost involved I gave serious though to moving up to a Kannad 406 Integra AF, which is less expensive than replacing the 406-AF and has a built in GPS receiver. But a careful study of the design, and a call to Kannad, confirmed that the GPS receiver in the Integra AF is only served by an internal GPS antenna. In other words, the GPS feature is useless in a metal skinned aircraft! This sort of nonsense is typical in the ELT world.

Here's a discussion of why ELTs are not so good and why PLBs or satellite messaging devices are a better choice:

You Tube

Here's a textbook example of how a satellite messaging device can get you home in time for dinner:

You Tube

I carry bug spray, too. It's important to be comfortable while waiting for your ride home

[JohnDixson]

Crab-good point re drag. With the departure of a healthy segment of blade, the Nr would upspeed. Does the Roninson have any sort of overspeed protection? or, is it possible the pilot saw the upspeed, thought overspeed and combined with the vibration made a bad choice?