That was a fairly broad statement Dynamic, would you care to elaborate? We just sold our 3 remaining B2's in favor of moving to an all Bell fleet, we feel that the safety, servicability, and economics are much better.
We now have an all Bell fleet, from 206B3's to 212's. We had 3 - 350B2's but sold them and bought more 407's. We currently have 6 and are looking at adding more. The 407 had been a very reliable and safe aircraft in our fleet.
I personally have over 2,000 hours on the 350 series, and now about 1,000 hours on 407's. My experience with the types is that the 407 is superior to the B2 in performance. All of my work is at altitude, and in a general charter / utility role.
I have had the unfortunate experience of attending 3 -350 accidents in my career, all of which have resulted in injuries and death. I feel that the 350 series does not offer the protection that other types do in a crash situation. The cabins of each of these 350 wreckages were demolished, and each aircraft was a complete write-off.
In addition to my personal experience in dealing with the aftermath of these accidents, I routinely study the information available on the NTSB website (www.ntsb.gov). This information may not be a complete look at a given type worldwide, but it is readily available and gives a good look at the US stats.
The 407, introduced in early 1996, has 20 reports filed, and is now numbering over 500 ships worldwide. There have been 15 fatalities, including a night wirestrike (4) several M/R blade strikes (3) a mid-air with a 355 (1 - 355 pilot fatal), but only approx 7 fatalities directly related to the failure of the aircraft/structure. in that same time period, the US 350 fleet had 60 reports and 50 fatalities. This is not an "apples-to-apples" comparison, as the 350 fleet numbers are larger.
Dynamic, you wrote..."There arent any Bell machines that can compare with the AS350". I disagree with this statement, there are several Bell models that can compare directly with 350B, BA, and B2's. I also suggest that if you feel that Hydraulic servo transparency is the only item of safety effecting a 350, you should do some research. There have been several AD's issued recently that could have a profound effect on your safety.
The 350's may be wonderful aircraft to fly, but do not be lulled into any false sense of security. When they bite, they bite very hard!
My point is comparing B2 to 407 is not apples to apples.407 has purchase cost about 300K usd more than b2 and DMC about $40 usd / higher ( like having a free pilot on the b2 LOL) . If you want to compare performance compare L4 to B2 and 407 to B3 .
Each has its ups and downs. The Bell vs Eurocopter thing has been going on for years like Ford vs. Chevy, and we may as well be arguing about our favorite colour. One could tit for tat for hours on end.
Dynamic, you'd be well advised to pay attention to 407 Driver. He is among the finest of helicopter pilots anywhere, and has reached a level of knowledge and experience in the Canadian Rockies that most of us can't even imagine. As you may have noticed, he doesn't talk through his hat, and can back up his words.
I can only speak from my own experience, which is operating 350s commercially for 1500 hours, and flight test on 407s for about 1000. I don't work for Bell anymore, and have no particular allegience to them or anyone else. I can tell you that I know the 407s problems intimately, but would not hesitate to operate one anywhere. It is a superb helicopter.
We have just over 200 AS 350s operating in Canada. They have had their share of growing pains, like anything else. The Turbomeca engine, once the savior of the type, is quickly falling out of favour due to reliability issues and horrid product support (Widgeon, a quick call to Irving in NB who operate a 350B1, L4 and 407 will enlighten you). In fact a 355F1, with two Allison engines has a lower operating cost than a 350B with one Arriel. You are correct that Conklin and DeDecker do indeed list the 407 DOC at $36 more than a B2, but I think the servicability issues and performance more than make up for it.
The hydraulic failures persist, in spite of being identified eons ago as a problem. In the past 8 years in canada we have had 9 reported hydraulic failures in Canada. Some of the belts had 200 hours.
In the same time, there have been 15 forced landings due to inflight power issues. Admittedly, it's likely that not all have been directly engine related, but that's still one out of every 13 helicopters in 8 years of data (assuming there were 200 A-Stars 8 years ago - and there was nowhere near that). Of the 25 407s in Canada, there have been two engine power incidents, one is still under investigation as to cause. There have also been 520+ production models and several thousand hours of experimental which have been built at Mirabel without a failure in flight test. Touch wood.
There have been several accidents involving main rotor spherical bearing failures. Very serious problem.
My biggest worry about them is the survivability in an accident. Lawn furniture surrounded by ping-pong ball skin. Give me that box structure of the 407 anyday. It's even stronger than the L with the added composite. Another misconception is that the 407 is an L4 with 4 blades. In fact, there is only 14% commonality between the two ships, and one cannot build a 407 out of a 206L-4.
Well, this thread is getting WAY off topic, but I'll respond one last time. Thanks CTD for those kind works.
Widgeon, I'd GLADLY compare my 407 to a B3 anyday, as you know, the B3 is a fantastic aircraft, but Eurocopter failed to raise the Internal Gross weight above B2 levels, (last time that I checked anyway) so all that power, but still only 4960 Internal? Given it's probable heavier EW than a B2, one would be worse off...unless you dare to depart over the Internal Gross wt?? You wouldn't do that would you?? Slinging, well, the B3 is great, no doubt about that!
We feel that our 407's are operated for less $$ than our B2's were, plus with some innovative purchase methods, (build them) we have aquired them cheaper than a 350. We had B2's parked in the summer for 5 weeks waiting for parts...figure that cost into your equations and the Bell products suddenly look more attractive.
I don't take safety lightly, and feel good about strapping into one every day. We have excellent maintenance personnel, who have developed some great ideas on dealing with T/R shafting balance issues, some of which have been incorporated into Bell's maintenance proceedures.
As CTD said, this is turning into a Ford-Chevvy debate. I initailly took up the issue re: the comment that Bell has nothing to compare....
today i experienced an oscillation in the eurocopter as350b3 for the first time. the b3 has just been returned to service after a 1500 hours (i believe). it had been flown a couple of times since then, until i departed the airport to ferry the helicopter out in the woods for sling load. i flew at 1500', 135 kias, 82% torque (90% on the fli, i believe), OAT 5 deg C. i had put lots (!) of friction on the collective, not touching the control, and gently keeping the cyclic to maintain the attitude. no turbulence in the area. suddenly, with no power or attitude changes, i got a oscillation up and down in the whole helicopter that corresponded to the main rotor rpm, same intensity, like the rotor system wasn't tracked properly. i gently reduced power just before the bleed valve opened (appx 91% ng) and the oscillation stopped. i returned to base with this power setting and landed normally.
i have heard of new b3's having this problem; but this was my first time. i want to make clear that this was no pilot induced oscillation, since the friction was almost max on, my left hand was on my thigh (until it had lasted for about 3-4 seconds), and i was not moving the cyclic, it was completely still. momentarily i thought it was turbulence, but it turned out to be rythmic. the technicians are checking the helicopter tomorrow morning, since i was on a night flight. my guess is that this could be the collective linkage (somwhere between the collective and the servo). is this the case? i have heard of other pilots who have had the same problem, and even worse oscillations than what i had.
the thing that worried me was that it came without any warning in smooth, calm air, with no changes in power/attitude, like lightning from clear sky, and disappeared when i reduced power.
I would have lot's more questions about the indications, ranges etc for you.
When you say "oscillation" do you mean a vibration in the rotor system or a movement of the airframe?
Were you close to vne?
What were these secondary indications; 1. TOT 2. N1 3. NR 4. Acft yawing back and forth?
5. Indicated airspeed change during the event? 6. Audible pressure change? 7. Change in groundspeed? 8. Close to vne?
If the secondaries 1 through 4 were varying I would work the engine/ bleed valve side of it.
5 through 8 would lean me towards unforeseen turbulence/ frontal passage/ lee eddies from something
If those were clean;
And the event was happening at a small power range I would work the engine some more,governor, power demand, load demand etc.
If it's a small airspeed range it's happening at I'd look at the rotor system/ flight controls from the blades back to the servos and then further back the chain to the place you do the touchy feely stuff to.
Keeping in mind that the flight control side of this problem is the most dangerous I would go through all I could on the ground first and with heavy emphasis on the flight controls.
Please let us know what your technicians find out,
(disclaimer....not a eurocopter guy, just tom generic)
May be applicable, may not be but I saw this in a CAA safety publication I received in the post yesterday.
SA350 - Cruise.
An investigation by the aircraft manufacturer into two reports of in-flight oscillation concluded that the problem was due to the Fuel Control Unit's ( FCU's ) lack of success in filtering drive train torsional mode. This 4Hz torsional mode causes velocity variations for which the FCU tries to compensate. However because the NTL ( free turbine ) and NG ( combustion chamber ) are in phase lag, the FCU doesn't solve the problem but sustains it. By modifying the flight conditions, the balance is broken and the phenomenon disappears.
It is noted - with no more stress on it that a pure mention - that this was a military Squirrel used for ab-initio training by the UK military.
Hope this helps. You modified the flight conditions - reduced power - and the problem disappeared, so this may be something after all.
Aircraft has started hitting the unsat side of the graph on a regular basis, after bouncing around near the line for the 10 months it's been here. We've checked for compressor section visually, looked for leaks, checked the free air temp and torque calibration. NG remains to be checked, and most interestingly, something internal to the module 5 of the engine. For which I've been requested to perform a "climb power check"-but can find no rotorcraft flight manual entry describing the test. If you can point me to it in the RFM, or describe the test and your experiences, I could sure use some insights...
I would perform a power check at 97%, 98%, 99%, and 100%. Look for a trend to see if you are generating progressively less power at higher settings, or 'better' power the higher the Ng you pull.
The 'climb power check' you are referring to is the 100% Ng setting. You have to climb in order to perform it. Try doing it straight and level and you'll see what I mean. Be careful not to exceed any airspeed/power setting limitations.
Pull the p2 filter and clean it. Perform an engine wash, and follow it with a thorough rinse. Pull all the stainless steel lines on the engine and check the flares for any sign of contamination, especially the fuel line. Run the engine with the cowl open to make sure there isn't anything leaking around any of the lines.
What has Eurocopter said about any of this? Have you spoken with a tech rep yet?