MD600
Join Date: Mar 2002
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Three police forces that I personally am (or was) acquainted with operate(d) the MD600, and all three made the decision to replace them with AS350B2s within two years. Main reason was poor performance in terms of load-carrying capability in hot/high conditions; secondary reasons were high maintenance workload and poor support by the manufacturer leading to poor availability rates.
Then, however, I’ve also met one or two (private) owners who swear by them. This suggests that
1. They are very good at some missions, and no good at all at others.
2. There is a huge variation in the build quality. It should be noted that for most if not all of the production run the manufacturer was in trouble / bankrupt /about to be sold / closing some production lines / or maybe not / etc. It’s hard to concentrate on your work when you’re wondering if you’ll have a job next week, a problem not confined to the helicopter industry.
Then, however, I’ve also met one or two (private) owners who swear by them. This suggests that
1. They are very good at some missions, and no good at all at others.
2. There is a huge variation in the build quality. It should be noted that for most if not all of the production run the manufacturer was in trouble / bankrupt /about to be sold / closing some production lines / or maybe not / etc. It’s hard to concentrate on your work when you’re wondering if you’ll have a job next week, a problem not confined to the helicopter industry.
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MD600
I am looking at the MD600. I will put up about 300 hours per year on the machine. Can anyone tell me its good and bad points, general impressions, power, service and availability of spares etc.
Thanks
cs
Thanks
cs
Join Date: Mar 2003
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Re: md600
Fast, economical and smooth in calm conditions, very neighbourly as it is so quiet, easy start up procedure, simple maintenance program. Poor visibility due to wide door frames, poor ride in turbulence, tricky CG situation when 6 up, no separate baggage locker.
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Re: md600
Entry into auto requires a large rearwards application of cyclic but once established in auto it's ok but you need to keep plenty of speed for tail rotor control on landing.
Join Date: Jun 2003
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Re: md600
I heared once that it is a real pain to autorotate because of its very high forward speed needed before flaring. Is this true?
When the NOTAR equipped aircraft were first certificated the FAA considered a requirement for a NOTAR rating with additional training and certification requirements. Looking back, this would have been an appropriate method to force pilots to receive proper training in the unique handling qualites of NOTAR equipped helicopters just as it has required R22 and R44 pilots to understand the unique requirements of those helicopters.
The MD600 is a high performance helicopter that requires specialized training if one is to utilize the full potential of the machine.
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MD 600 Stability Augmentation System
i am curious about what knd of Stability Augmentation System the MD600N might have, if any. if any one could explain what it does and how it does it i'd be very grateful. and if anyone could answer a "hypothetical" question for me;
if the system was unservicable (or disabled) would it cause any undue oscillatory loads on the tailboom mounting hardware which may cause it to fail?
thanks in advance
FP
if the system was unservicable (or disabled) would it cause any undue oscillatory loads on the tailboom mounting hardware which may cause it to fail?
thanks in advance
FP
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The system the MD600 is fitted with is called YSAS, which stands for Yaw Stability Augmentation System.
It is controlled by a yaw rate gyro under the front seats, which acts upon an actuator attached to one of the vertical stabilisers.
In the event of any part of the system failing, you can simply turn it off! This will not cause any negative effect or strange flight characteristics.
If you want any more info, please drop me a PM, I am more than happy to explain the system and discuss the failing for the tailboom attachment hardware in more detail.
For interests sake with the VSCS system on the MD900, which is a similar idea, if it fails it has a tendancy to cause a Dutch Roll above 100 knots.
It is controlled by a yaw rate gyro under the front seats, which acts upon an actuator attached to one of the vertical stabilisers.
In the event of any part of the system failing, you can simply turn it off! This will not cause any negative effect or strange flight characteristics.
If you want any more info, please drop me a PM, I am more than happy to explain the system and discuss the failing for the tailboom attachment hardware in more detail.
For interests sake with the VSCS system on the MD900, which is a similar idea, if it fails it has a tendancy to cause a Dutch Roll above 100 knots.
Join Date: Mar 2003
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does this have any thing to do with c-ftaz ?
http://www.ntsb.gov/ntsb/brief.asp?e...04X00392&key=1
http://www.ntsb.gov/ntsb/brief.asp?e...04X00392&key=1
Its RN011 which makes it extremely unlikely to have YSAS fitted - I believe the earliest fits as standard would be around [or beyond] the RN060 mark, could be a retrofit though.
I have just confirmed - it is an ex-LA County Sheriff's machine, no YSAS when they got rid of their fleet.
I have just confirmed - it is an ex-LA County Sheriff's machine, no YSAS when they got rid of their fleet.
Last edited by PANews; 14th Apr 2006 at 21:42.
Join Date: Nov 2001
Location: San Jose, CA
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I'm not sure if the 600 shares any bits with the 500N but at any rate the link below makes for interesting and sobering reading, and some parts of the 500N's YSAS play a part which is why I elected to post it here.
Note that the pilot's concurrent H-60 experience apparently worked against him. From what I can glean from this report, the pilot needs to be extremely aware of and proficient in dealing with failures that are somewhat unique to at least the 500N, and/or its particular type of YSAS hardware.
http://www.ntsb.gov/ntsb/brief.asp?e...12X19976&key=1
Dave Blevins
Note that the pilot's concurrent H-60 experience apparently worked against him. From what I can glean from this report, the pilot needs to be extremely aware of and proficient in dealing with failures that are somewhat unique to at least the 500N, and/or its particular type of YSAS hardware.
http://www.ntsb.gov/ntsb/brief.asp?e...12X19976&key=1
Dave Blevins
Sooooo....this wonderful NOTAR system that everyone is all ga-ga about is actually *more* complicated than I had imagined! I have to admit that over the years I haven't devoted much brainpower to the mechanics of how a NOTAR works. I just assumed it was an engine-driven fixed-pitch fan and a Coanda slot or something. Like SWP/VRS/LTR, I figured that the NOTAR was just another bunch of PFM. Silly me!
A driveshaft to the fan - so far, so good, just like every other conventional helicopter. Now to this we add a fenestron-like pitch-change device for the fan, *and* another method of swivelling the thruster, *and* (in some ships) a YSAS controller to pivot one of the vertical fins. Holy complications, Batman! Did Rube Goldberg design this? And this system is supposed to be "better"...why? Ohhhh, that's right, no tail rotor for people to walk into or to smoosh into the ground during those dreaded nose-high landings.
In the case of the San Jose, California P.D. crash, it seems to me...and hey, I could be wrong...but if it is correct that the pilot initially experienced a yaw to the right, then he probably thought he had a "tail rotor failure" and closed the throttle.
MDHI's contention that he was coincidentally having a anti-torque problem and a high-side governor failure (talk about a bad day!) would be laughable if the guy hadn't died.
Closing the throttle kept that fan turning at it's normal speed and thrust, which probably put him into the uncontrollable left spin. In the scant few seconds between the failure and impact (which is all we ever get in helicopters), I'm sure that between his mayday calls, the PD pilot was thinking, "WTF is going on with this damn thing?" Too bad he didn't have just a few more seconds. Maybe he might have figured out what was going on and rolled the throttle back on.
Sad.
NOTAR, great idea, MDHI! Not.
A driveshaft to the fan - so far, so good, just like every other conventional helicopter. Now to this we add a fenestron-like pitch-change device for the fan, *and* another method of swivelling the thruster, *and* (in some ships) a YSAS controller to pivot one of the vertical fins. Holy complications, Batman! Did Rube Goldberg design this? And this system is supposed to be "better"...why? Ohhhh, that's right, no tail rotor for people to walk into or to smoosh into the ground during those dreaded nose-high landings.
In the case of the San Jose, California P.D. crash, it seems to me...and hey, I could be wrong...but if it is correct that the pilot initially experienced a yaw to the right, then he probably thought he had a "tail rotor failure" and closed the throttle.
MDHI's contention that he was coincidentally having a anti-torque problem and a high-side governor failure (talk about a bad day!) would be laughable if the guy hadn't died.
Closing the throttle kept that fan turning at it's normal speed and thrust, which probably put him into the uncontrollable left spin. In the scant few seconds between the failure and impact (which is all we ever get in helicopters), I'm sure that between his mayday calls, the PD pilot was thinking, "WTF is going on with this damn thing?" Too bad he didn't have just a few more seconds. Maybe he might have figured out what was going on and rolled the throttle back on.
Sad.
NOTAR, great idea, MDHI! Not.
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Pprune, have you flow the 520/600? I have a bunch of hours in them, and although I do not care for them, you need to do a little more research on the San Jose crash.
My interest woudl be what failed on the helicopter. There was a modification several years ago on the tail attatchment points. Was this enough, or not. One of the pilots I fly with is the one that during pre-flight wiggle the tail and watched it wiggle and the main fuselage didn't
.
My interest woudl be what failed on the helicopter. There was a modification several years ago on the tail attatchment points. Was this enough, or not. One of the pilots I fly with is the one that during pre-flight wiggle the tail and watched it wiggle and the main fuselage didn't
.
HeliMark: Pprune, have you flown the 520/600? I have a bunch of hours in them, and although I do not care for them, you need to do a little more research on the San Jose crash.
I do? Hmm. I based my comments on the NTSB report, which I thought was quite detailed as far as the operation of the anti-torque system on the NOTAR ships. If you disagree with the NTSB report, you could share it, I guess. Or you have other, additional information about that accident, please feel free to post it (or a link).
And no, I have not flown the 500/600 series, and that is not relevant.
What failed on the San Jose ship? There was no indication from the NTSB that there was any structural failure, only that the cable controller for the thruster, after wearing away due to "stress corrosion" for awhile, finally separated. I understand from the report that the fan remained powered. Is that not correct? The NTSB report said that witnesses reported erratic yaw moments just before the final plunge. Afterward, the throttle was found in the Ground Idle position.
There was an assumption that the ship at first yawed to the right, as it would during a tail rotor failure in a conventional helicopter. The report further goes on to speculate that this is when the pilot rolled the throttle off to enter autorotation, transferring the H-60 tail rotor failure procedure to the MD ship. The assumption is that this is what caused the left spin down to the ground at "one revolution per second." (Spin your computer chair around at 360 degrees/second to see just how fast that is! And in your chair you are at least right on the center of rotation, which is bad enough. In the MD500N you are, what, three feet or so forward of the center? Wow.)
So what am I missing here? What did I not understand? No pilot in his right mind is going to roll the throttle off with an uncontrolled left yaw. In such a case, taking the torque away will make matters worse. So my comment is merely that the S.J.P.D. pilot misdiagnosed the situation and performed the wrong corrective action resulting in his unfortunate demise.
I have no particular beef with the MD product line. But after all the oohing and ahhing over the NOTAR when it first came out, I guess in the long run it's no better (and might even be a little worse) than the conventional tail rotor system as God and Igor intended.
I do? Hmm. I based my comments on the NTSB report, which I thought was quite detailed as far as the operation of the anti-torque system on the NOTAR ships. If you disagree with the NTSB report, you could share it, I guess. Or you have other, additional information about that accident, please feel free to post it (or a link).
And no, I have not flown the 500/600 series, and that is not relevant.
What failed on the San Jose ship? There was no indication from the NTSB that there was any structural failure, only that the cable controller for the thruster, after wearing away due to "stress corrosion" for awhile, finally separated. I understand from the report that the fan remained powered. Is that not correct? The NTSB report said that witnesses reported erratic yaw moments just before the final plunge. Afterward, the throttle was found in the Ground Idle position.
There was an assumption that the ship at first yawed to the right, as it would during a tail rotor failure in a conventional helicopter. The report further goes on to speculate that this is when the pilot rolled the throttle off to enter autorotation, transferring the H-60 tail rotor failure procedure to the MD ship. The assumption is that this is what caused the left spin down to the ground at "one revolution per second." (Spin your computer chair around at 360 degrees/second to see just how fast that is! And in your chair you are at least right on the center of rotation, which is bad enough. In the MD500N you are, what, three feet or so forward of the center? Wow.)
So what am I missing here? What did I not understand? No pilot in his right mind is going to roll the throttle off with an uncontrolled left yaw. In such a case, taking the torque away will make matters worse. So my comment is merely that the S.J.P.D. pilot misdiagnosed the situation and performed the wrong corrective action resulting in his unfortunate demise.
I have no particular beef with the MD product line. But after all the oohing and ahhing over the NOTAR when it first came out, I guess in the long run it's no better (and might even be a little worse) than the conventional tail rotor system as God and Igor intended.