R44 Missing North of Montreal

[aa777888]

Originally Posted by 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?

No overspeed protection system. Not even a warning system other than the tach. Just the pilot's hands on the throttle and collective.

[Hot and Hi]

Originally Posted by aa777888

other than the tach. Just the pilot's hands on the throttle and collective.

Arguably that’s exactly where you will be looking in such a situation. So no warning lights needed.

[[email protected]]

With the departure of a healthy segment of blade, the Nr would upspeed.

John, that would assume it completely detached rather than peeling back and creating extra drag

[[email protected]]

The 'cheap pilot bastard' from AVweb forgot that 406 beacons also transmit on 121.5 so you get the best of both worlds.

He also forgets how many false alerts there were when 121.5 PLBs were monitored by COSPAS / SARSAT, no-one moaned about going out looking for them then just as no-one moans about going out investigating 406 alerts.

Just buy a 406 ELT and get it mounted properly - AND carry a personal one.

Relying on your cell-phone is fine if there is a mast near you but otherwise is even less useful than a 121.5 beacon no-one is listening to. How many pilots would actually recognise the beacon signal as a distress one?

You have to be overdue and have search action initiated before the authorities start pinging cell phones so you could still be waiting quite a while.

As an ex-SAR pilot, I would have an aircraft ELT, a personal ELT (both 406) and carry my cell phone - guess what I do every day I go flying?

Be a 'cheap pilot bastard' by all means but don't come crying when you die alone in the woods because you didn't have a 406 beacon.

[Hot and Hi]

Crab, do you understand how sat trackers work?

[JohnDixson]

Sorry, Crab seems I misread the report wording. When I read “ broken “ I just assumed the huge centrifugal force would carry the outboard segment away.

[[email protected]]

Crab, do you understand how sat trackers work?

yes thanks, and I know you can't home to them like you can with a 121.5 emitting 406 beacon. You also can't home to a 406 beacon because it isn't a constant transmission, just a burst transmission every 50-odd seconds or so - that's why they tx on 121.5 as well.

PLBs/ELTs on 406 don't need subscriptions and have better coverage than personal sat-trackers

[aa777888]

Originally Posted by [email protected]

yes thanks, and I know you can't home to them like you can with a 121.5 emitting 406 beacon. You also can't home to a 406 beacon because it isn't a constant transmission, just a burst transmission every 50-odd seconds or so - that's why they tx on 121.5 as well.

PLBs/ELTs on 406 don't need subscriptions and have better coverage than personal sat-trackers

This sort of thing is actually my specialty. My main work is producing complex RF systems. There is some detail lacking here that it might be helpful to fill in.

As crab correctly states, the 121.5MHz signal is required for conventional (practically "classical" at this late date) homing, aka direction finding. There are some subtleties here associated with more complex equipment that could actually geolocate 406MHz bursts, but such capability is rarely found in a SAR operation.

However, and most important, there are two types of 406 beacons. The first only transmits an identifier that, if properly registered, identifies the aircraft specifically. This is a great help in resolving false alarms, but does not improve the satellite-based geolocation performance much above that provided by the older 121.5MHz-only ELTs. These 406MHz signals require many tens of minutes to sometimes hours to geolocate, the same as the old 121.5MHz signals. And geolocation accuracy is poor, typically resulting in a 4KM radius to search, again similar to the 121.5 beacons.

The second type of 406 beacon incorporates either an interface to an external positioning system, usually GPS, or an integral positioning system, again GPS. Such ELTs completely eliminate the requirement for homing. They transmit a precise position to the Cospas-Sarsat system, with accuracy of well inside a 100M radius, and do this within just a few minutes at most. This position is then relayed to SAR assets. They are thereby a huge step up from the non-GPS equipped or interfaced 406 beacons. Indeed, these days it is sheer folly to not be so equipped. And yet most aircraft ELTs in general aviation are of the older, non-GPS equipped 406MHz type.

As in much of aviation, regulatory aspects are cost drivers and prevent rapid innovation. Hence, as crab and I both have already suggested, obtaining a modern PLB, which will undoubtedly include a built-in GPS positioner, is of very high value.

This brings us to the statement above regarding "personal sat-trackers", more properly called "satellite communicators". While it is true that these do require a service plan similar to a mobile phone, you do get what you pay for. They provide functionality over and above PLB/ELT/EPIRB systems, most notably two-way text messaging and periodic tracking updates a la Spidertracks and other similar, commercial tracking services. With respect to their coverage they actually can perform better than the Cospas-Sarsat system. If you are down in a canyon or other steep territory, it is possible that the GEOSAR satellites will not be in your field of view. In such a case you have to wait for a MEOSAR or LEOSAR pass to see (have radiofrequency line of sight to) your beacon. That can sometimes take hours, depending on the present geometry of the Cospas-Sarsat satellites. The same is not true with satellite communicators (or the commercial sat-tracker systems). These all rely on either the Iridium or Globalstar constellations. Both of these systems use a great many satellites in low Earth orbit, and thus passes over steep terrain will occur much more frequently. When choosing between the two systems the only thing to consider is that there is no polar coverage for Globalstar, while Iridium has complete global coverage. Bottom line: commercial satellite communicators, in particular those using Iridium, and specifically the Garmin inReach products, are the gold standard for rescue communications and location, lacking only G-switch activation. The lowest priced plan in the US is about $140USD a year if you never send or receive any text messages or send any routing position reports.

Of course the best answer is to "get both". And carry other tools to get found fast and solve the last 100M problem, such as whistles, mirrors, lights, handheld aviation radios, etc.

[aa777888]

Sorry for the thread drift, but ELT functionality was a featured part of the accident report. There's no question that a lot of other very bad stuff lead up that point.

[Robbiee]

Originally Posted by aa777888

No overspeed protection system. Not even a warning system other than the tach. Just the pilot's hands on the throttle and collective.

Actually, according to a POH update I saw recently, there's now a high rpm warble type of audio warning. However, like the "full throttle light" I have yet to see one in an actual Robby.

[blakmax]

This report makes interesting reading from an adhesive bond failure forensics aspect. Probably one of the more important factors is the suggested lack of bond between the core and the rear of the spar. This bond is formed using an expanding foam adhesive that fills part of the gap between the core and the vertical face of the spar. An inadequate bond there has significant influence over the blade behaviour. That foam distributes shear loads from the core into the spar. Normally, the shear loads are not great, mainly because the adhesive shear strength should be orders of magnitude greater than the shear strength of the core itself. However, if that bond is ineffective, then the shear loads can only be transferred through the upper and lower blade skins placing peel stresses on the adhesive bond between the skins and the upper and lower faces of the spar. This may over time lead to fatigue damage in the spar to skin bonds. Given that the observed disbond in this joint on the lower skin occurs at about the middle of the region where the lack of foaming adhesive bond is reported, then this may be a significant contributing factor in this event.

In defence of RHC, it is impossible to inspect the bond between the core and the rear of the spar, either immediately after production or in subsequent service. One consequence of an absence of this bond would be a localised loss of torsional stiffness over the defective bond length, but even that would be difficult to measure.

I am surprised that -5 blades are still in service. I personally would suggest that trying to squeeze the last few hundred hours of life out of these old blades is false economy.

Regards

Blakmax

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This is why thread drift is good because people do have areas of expertise that might not otherwise be uncovered if we just stick tightly to the thread theme.

Good post aa777888 - I was told that even with the newer 406 beacons, the important positional information is included in the second half of the transmission burst and that can sometimes be missed off or corrupted.

Classic (violet picture) homing is still essential in difficult terrain and when there are multiple beacons. I have homed to 243.0 and 121.5 transmissions in mountainous and forested terrain where 100m can make a huge difference to where you put the search teams.

The only problem with the sat-trackers is that you have to be conscious to use them, much like a personal ELT whereas a correctly installed aircraft ELT should Tx providing it survives the impact.

M32K - you are right but there is enough evidence in the report to show a lack of aviation professionalism or even self-preservation that seems all too common in the light helicopter owner-community, that is not to tar all with the same brush but we keep seeing common and very human failures in these type of accidents. Darwinism at work I suppose.

[Arnie Madsen]

For the life of me I could never comprehend why RHC continued with the problematic R22 style blades when they came out with the larger R44 machine

A wrap around skin over the spar would eliminate those de-bond issues once and for all. Many more square inches of adhesive surface , nothing to allow moisture to penetrate , no lifting edges exposed to 300+ mph airflow .

[aa777888]

Originally Posted by Robbiee

Actually, according to a POH update I saw recently, there's now a high rpm warble type of audio warning. However, like the "full throttle light" I have yet to see one in an actual Robby.

Interesting! In further reading, it would appear that this is a feature of the new engine monitoring units (EMU) they are putting in R44s now. Thanks for pointing that out! And long overdue. It is beyond me why they did not also implement a power indicator function similar to the Cabri in the design of that unit as well. To answer my own question, perhaps because then it would become a primary flight control component and required additional certification.

[aa777888]

Originally Posted by blakmax

I am surprised that -5 blades are still in service. I personally would suggest that trying to squeeze the last few hundred hours of life out of these old blades is false economy.

This accident occurred before the replacement deadline. And they were -2's, not -5's, not that it makes any practical difference as both were subject to the same AD. There shouldn't be any -2's or -5's flying anymore, but there probably are some in countries with weak aviation safety discipline.

[212man]

Originally Posted by Hot and Hi

Crab, do you understand how sat trackers work?

I nearly spat my coffee out!

[malabo]

Sat tracking and relative value is influenced by where you work and what you do. All SAR professionals that I have dealt with in Canada are heavily in favour of it. Every company I have worked for in the past 10 years has sat-tracking. Anything I fly now either has sat-tracking or I bring my own. Given a choice between carrying a PLB and Sat tracking, I'll go sat-tracking every time. 406 vs 121.5 ELT? You're still in the lighting a campfire and sending smoke signals age of rescue, times change. With sat-tracking you'll be in easy 121.5 homing range, if not within 5meters. ELT's fail to work properly 60% of the time. If you are incapacitated you'll never get that PLB out of your bag, but the sat-tracker may just keep blipping out your location. I even give my passengers a spare tracker to keep in their pocket (would have helped the passenger in this crash).

SAR resources here now are also increasingly using cellular phone tech for triangulation and "last ping range" to focus on specific search areas. Always carry a cel phone, and never tell your passengers to turn theirs off, unlike airlines.

One more wealthy guy with his own helicopter that did not get the professionalism required to operate in the remote bush, where you can't just land in a field by a highway and call Uber. And sat-tracking isn't only for the wealthy: 2 minute unlimited tracking all year for less than a tank of fuel, trackers for 1/4 of that. Darwin.

[[email protected]]

All fair comments Malabo but you have to reach the private owner or 'cheap pilot bastard' as referred to in the AVweb video - they appear to be the ones who will baulk at spending the money and doing things properly - ironically they are the ones most likely to need assistance when it all goes wrong.

I have spent a big chunk of my career rescuing, or sadly recovering the bodies of, people who didn't think it would happen to them - some just unlucky but plenty just foolhardy or ignorant of the dangers - this guy seems typical of this mindset.

Whilst the coverage from the Iridium satellites is impressive, your tracker still needs to have a clear view of the sky to see them so not infallible. I would have a belt and braces 406 beacon as well.

[aa777888]

Originally Posted by [email protected]

Whilst the coverage from the Iridium satellites is impressive, your tracker still needs to have a clear view of the sky to see them so not infallible. I would have a belt and braces 406 beacon as well.

406 beacons also need a clear view of the sky. Actually, they need a clearer view than that required by Iridium and Globalstar based devices. Re-read my post on this above.

There is absolutely nothing substandard about the Iridium and Globalstar based devices except for the lack of a G-switch. Other than that in most ways they are superior to 406MHz devices. Again the best solution is to have both.

[[email protected]]

Again the best solution is to have both.

Agreed .