Yes, although note its in a section entitled "manufacturers review of recorded data" so once AAIB realise its wrong, they will be able to blame the French!

Fully developed Vortex Ring will give you 6000', the report does state "...vortex-ring state entry condition..." so 1000' to 1800'/Min is entirely reasonable. It also says that the ac went from 240' / 24%Tq / 1000' per min to 1800' per min by 100' even though he now had 115% Tq on. Sounds like pulling power made it worse, which could also indicate the onset of VRS.

No arguments from me there though!

Or perhaps an under reliance? Use of the 4th axis, IAS hold, would have prevented this. The L2 cannot match a 225 in the quality of its 4 axis ability, but it usually manages pretty well and there has to be a good reason not to use it in a scenario such as this.

The "grapevine" informs me that the captain had fairly recently come back onto the L2 after being on the EC225.

I leave it to HC to derive the various possibilities and potential for this to exacerbate the risk of human error.

If my information is wrong, I apologise now.

HC,

The second time I went to the linked report some additional pages showed up.....which answers most of my questions which came after the first go.

Perhaps part of it did not load or something.

Colibri

When asked in an oil and gas forum both EC and CHC said that this was not the case.

With apologies to Isaac Newton for the shoddy rate of change calculation, but 100 feet in two seconds sounds like 3000 feet per minute to me.

Should aircraft have an AFCS mode which will kill you if you don't pay attention? Yes it is fundamental to being a pilot to monitor your instruments but this issue should be pushed out to mitigate the risk a bit. Basic 3-axis vertical modes (ALT, VS) are just plain dangerous if you don't know the risks at low collective settings. Want to scare yourself next time you're up? Just engage ALT at height and put the lever down. Watch the airspeed wash off and the aircraft fall out of the sky. Horrific.

GipsyMagpie

I can't believe I'm reading your last post - maybe it's time you reconsidered your career. You're not really going to tell me that an ATPL/CPL needs to be warned that low collective settings can result in excessive rates of descent when the AFCS is coupled to VS are you?? If so you just should not be flying - your understanding of basic physics, let alone absorption of training, is simply inadequate.

With regard to the hazards of AFCSs, just how much nannying do you want? So you want 4 axis? And who or what is going to ensure you put the correct parameters into the system? The frequency for the ILS even? Maybe you'd like the whole lot automated so you can sit there all day doing nothing?

The more automation you have the more scope for boredom, over-reliance and degradation of monitoring and even hand flying skills. Of course there is a balance - no one is going to advocate SP hand flown ILSs. But given the number of instrument approaches that are flown quite acceptably with 3 axis AFCS systems, the current balance is well within the scope of two well trained pilots, concentrating on the job.

Maybe in this incident use of AS hold rather than VS would have been better - at least then the consequence of inadequate power set would have been a higher ROD from the outset and when the radalt warning sounded, assuming neither crew picked up the ROD cue, pitching up into a climb with the heave of collective would have avoided the VRS that took them into the sea.

There wasn't much automation in the S61 that BAH flew into the water in 1983! I don't believe this is an automation issue - it's a monitoring and awareness issue.

Try switching off the cylic trim then letting go of the cyclic - that's pretty horric too.........:rolleyes::rolleyes:

Absolutely Spot On!

Ask yourself which Flight Control was most crucial in this whole thing....and which parameter is the one that is required to change to carry out the maneuver?

In this case....altitude change was the primary focus and airspeed could have been left alone from the start.

I know it sounds a bit elementary to suggest a well trained crew can not adjust two parameters simultaneously.....and that is not what I am saying.

If an Approach Airspeed had been set first.....then the descent initiated.....then an incorrect power setting would have been the very first thing to show up and be corrected as the Collective would have been an "Active" control. One Pilot would have had his grubby mitt busy working the Lever to maintain the ROD while the AFCS was maintaining the Airspeed.

Be the Approach Speed been 110 Kts or 80 Kts......it would have made very slight difference. It is not like the aircraft were lined up by the dozens to land at Sumbrugh that day.

Unfortunately for Duncan, people are going to jump to conclusions. An outsider, reviewing CHC's strategy of selling off their training assets and outsourcing a good chunk of their training for no reason other than increasing capital and profit, would conclude that they were not really interested in quality of training, merely ticking a box to satisfy the minimum standard.

Personally, having done my L2 conversion at CHC I am aware that the standard was similar to Bristow at the time (10 years ago), although I do wonder if that is still the case, despite the best efforts of the folk at the sharp end. Not many outside observers are in my position though.

HC - you need to clear some space on your PM box!

I don't know about the L2 training, but having completed a 332L conversion with CAE in Stavanger, I can only comment on my experiences. The standard of simulator training was outstanding! The pre-session briefings were the best I have every had in 35 years of military and civil flying. Once in the sim, the pace and content were again spot on, perfectly tailored to the crew's experience levels. Having spent 11 years at Bristow, I can honestly say that the CAE training was as good if not better.
I don't think the standard of training per se is the reason this tragic accident occurred. It was, as always, a combination of human errors, from the design of the AFCS system, through company management culture to the pilots themselves. And not forgetting the oversight, or lack of, by the CAA?

bondu

26500-done

Bondu - not saying CAE training is bad necessarily, just that outsourcing your training as a policy looks bad for a large/mainstream operator. Although I think there will be an element of pot luck as to whether you get an instructor with any experience on type or in role.

The other issue is the flexibility that being in control of your own simulator brings. Not an issue when things go to plan, but when you have a candidate who is marginal and really needs more training, there is a strong temptation to just pass them because you know that there is no more sim time available at short notice, and anything else is too difficult. This is something I found a problem at Helisim, but not once we got our own ones.

Of course its not "required" to have your own sim, but when you do, to sell it is a big backwards step that says a lot to an outsider about your attitudes.

I agree with Bondu. Having been a sim instructor (on the 332s in fact), I know the guys who instruct full time provide better instruction than pulling guys off the line to instruct part time, which was my role. My experience with CAE instructors has been first rate.

However is it also not true that you can get a job with CAE, do a type rating course in the Sim, and then instruct on it having never flown it, and maybe never even flown offshore? This doesn't mean that your instructional technique will be poor, but I suggest you will lack an insight into the real world of operating that type in that role.

Time History
 

The time-history included in the report raises a few questions.

A 40 degree heading change at the end, yet the pedal position isn't on the trace.

The derived radio altitude rate does not square with the rate one derives by taking the slope of the proportional traces of baro and radio altitude at the end. Radio altititude rate signals have been suspect in other applications.

VRS, at least in the SA models I've been exposed to, typically results in a significant increase in cockpit N/rev excitation. Would be good to see the accelerometer traces along the same timeline as the Figure 1 data. On the same plot, would be ideal.

Seems a rush to judgement and perhaps a too convenient action to just hang it all on VRS, at least based on that one Figure as presented.

Would be helpful to see the AFCS/Autopilot commands and actuator out puts along the same time base.

Hi john

Yes, I noticed a bit of a "disconnect" between the radalt and the derived vertical speed at the end. You have to remember that the L2 was designed in the late 80s and certified in the early 90s and as such, has limited "extra" parameters on the FDR and mostly at the minimum sample rates. I think the lat and long accelerations are only at 4Hz and might even be 2 Hz, therefore well below the Nyquist frequency for 1-per-rev vibration. Also I'm pretty sure that only the pilot's control positions are in the data frame, not the AFCS series actuator outputs. The low sample rate might also explain the radalt / vertical speed disconnect - maybe they hybridised their VS parameter with some integrated normal acceleration data - that parameter being the one with the highest sample rate.

Time History Data
 

Thanks, HC.

I was referring to the 4/rev excitation, not the 1/rev, but as you wrote, perhaps the sample rate didn't support that range ( I didn't work it out, but am sure its 16-21 Hz or so ).

Is it possible that the AFCS/Autopilot Computer has some memory built in? If so, I'd bet that it would have the frequency range to assist.

Think they didn't put up the directional control trace because there is none? Most surprising if true.

All in all, one would hope that there is a lot more applicable data to review than that published in the single figure. I have to believe that the pilots office at EC is into this 100% and can assist. Just guessing, but would not be surprised if they took the VRS sedative with some skepticism as well.