MD600
 

FYI for all those who fly the 600. Both Sheriff departments in So. California, and I have also heard Border Patrol have grounded all of theirs. Started with L.A. County finding a broken mounting bolt for the tailboom to the fuselage. Then Orange County found an enlongated bolt and stress cracks. L.A. County went back and found all of the ones they have to have stess cracks. I have heard that Border Patrol has found cracks also.

Just info as the normal process can be slow, and the results of the boom coming off is something that I would hate to hear about.

i have been sent some photos of the la sherrifs but i was not aware of the same problems with the border patrol
is there any border patrol people out there to confirm they are grounded
hover bover u anything to say
regards all

Ha Ha ,
Guess what, on our 2nd 600s first 6 month/100 Hour one of the captive nuts (of which there are 4 which hold the bolts which hold the tailboom on)was stripped so only 3 M8 bolts holding tailboom on !!!! It seems the captive nuts are spliting if over tightened, then you cant change the captive nuts without deskinning part of the airframe!

I hadnt heard about the splits around the bolts, but I know that the slots in the tailboom are prone to cracking at the end of the slot!There has also been a mod to the tailboom around the bolt holes, it was a complete new tailboom part No. though I think, from memory Im sure ithad something to do with the holes in the tailboom having metal inserts or something.

It aint fallen off yet !!!!

Regards

Hover Bover.
PS
Hows the fadec Mr 600, all fixed !!!!!

Check the maintenance manual to see if it calls for a dry torque. If it does, check if the mechanics are adding a bit of anti seize compound (or other kind of lubricant). In some cases the mechanic will add this compound or some lubricant because he feels that the boom is on for life and if it ever has to come off the lubricant will make it easier to break the torque on the bolts and captive nuts. This was a major problem on B-214s and AH1-Js in Iran. The anti seize or lubricant can double or triple the tensile stress on the bolts and the bolt and nut threads causing the bolts to fracture or the nut to fracture.

I would like to add this, sometimes the maintenance manual does not address wet or dry torques. I would strongly suggest you check with your techrep and have him check with MD Engineering.

[ 29 October 2001: Message edited by: Lu Zuckerman ]

hover bover

yes fadec now all ok. had a eng out the other day with 110 lbs in the tank there was no fuel in the hmu
auto from 70 ft i now know i can do a auto on my own [big thanks to mike at mdhi mesa ] i never knew if it was me or him that did the last bit.

got some other pics of cracks on la sherrifs if you want them regards

I noticed with interest that MD states that the cracks are not "flight critical".

This is probably a factual statement, as if all the MD-600's in the world never flew again, would anyone notice? :eek:

To: Cyclic Hotline

Assuming that MD Helicopters performed an FMEA as a part of the design process it may have been determined that three of the four bolts are capable of reacting all normal structural loads. It would also be assumed that the inspection program would uncover the defective nut or bolt and it/they would be replaced before further damage could occur. However one poster indicated that the boom or fuselage had to be deskinned in order to access the captive nut. This is poor design and if the nut or bolt are not accessible then the remaining three bolts would be operating at a higher stress level and be subject to failure. If this were the case the remaining two bolts would be incapable of reacting the loads and would eventually fail and there goes the boom.

[ 01 November 2001: Message edited by: Lu Zuckerman ]

Could someone explain to me. Why the nuts would be affixed to the airframe. Is this because difficulty of access. Does anyone have photos to display?

capt notarios send me your email; i will send photos to you regards

On many helicoter designs the bolts and or the nuts are accessible from the outside. If the helicopter must be deskinned to gain access then it constitutes poor design. On some larger helicopters you you can acess the nuts and bolts from the inside.

To: Capn Notarious

On a good design the nuts are of the barrel type and are not attached to the airframe. On this type of installation the nuts are installed from the outside and slid into pockets in the airframe. On other larger helicopters the nuts and bolts are of conventional design.

[ 03 November 2001: Message edited by: Lu Zuckerman ]

MD600
 

Anybody flying the MD600N? How about the good, bad and ugly on this ship? How was the transition? Appreciate any feedback.

You want one? L.A. Sheriff is selling all three of theirs. Although they are the "newest" of the fleet, they are the first to go (fleet is being replaced by AS350-B2's). And that has every pilot except one, dancing. <img border="0" title="" alt="[Big Grin]" src="biggrin.gif" /> . .. .Really, although the new "YSAS" helps them, it only covers up the problems they have. They are a 500 frame designed for 420hp now putting out 600hp+. They are having cracking problems in the internal structures. And I do not believe we have seen the last of it.. .. .They are a handful in turbulance. In a right hand turn, the fusalage covers the airflow over the tail (at slow speeds) and due to this, it will tuck its nose down and spin to the right. You can stop it, just that it will do it. L.A. Sheriff has always practiced full touchdown auto's (and have some bent frames to show), but will not do it in the 600. If there is a crosswind, the 600 will turn itself into the wind during the flare, and you can not stop it. Add the 400 foot+ skid to go on top of it after the flare.. .. .They have wind limitations in relationship to weight and altitude, which puts a big damper on it operating at high altitude.. .. .Nick will be able to say it better, but look at the rotor blades. They are designed for the 520N (okay, the 500 with a foot more), not the 600. All they did was put the sixth blade on. You can point to most of the problems with it as the blades not able to handle the power and weight.. .. .And it really needs hydraulics!. .. .But it really is fast. And accelerates faster then most any other ship.. .. .Transition is fairly easy if you have NOTAR time. It you have no NOTAR time, it takes getting use to the tail and how it reacts (slow). The tail takes a lot of horsepower to run it and in an auto, that translates into a lot higher rate of desent.. .. .Although there will be some on here that like them, you can see I do not.

Sorry Helimark,. .. .I would have too disagree ! The 600 will only tuck its nose when flown out of trim, not in a balanced turn to the right. Its to do with the air traveling across the nose of the A/C, thats why it has that funny serrated foil up the screen, to try and disturb the airflow. But I agree it will tuck its nose. Biggest time to be wary is not actually in the turn to the right but when transitioning away with a strong wind from the port side, as if you arent flying the ball and you are keeping the skids straight across the ground it will tuck its nose as you are effectively flying out of trim, and you will quickly learn as its a real attention grabber!. .. .Autos are no biggy, but if you are used to a jetranger then I guess it could be interesting.. .. .It flys quick and very smooth, as helimark says the notar has its quirks but I guess you get used to them, the 600 is great for putting in five people and flying quick for 2hrs 15mins. .and putting down again, It is not good for slow speed flight ( I would guess that is why all of the law enforcement dont like them) Keep the 600 between 40 and 140 knots and its happy, fast transitions are the way to go , the less time spent between 15 and 40 knots the better.. .. .Got about 400 hours on the 600, and no major problems just as long as the tailboom doesnt fall off. LOL.. .. .Regards. .HoverBover

I do not know anything about the MD600 from personal experience, only a few passing comments from friends and colleagues who have operated them and the 520. Never heard anything good about them.

I would qualify that statement by adding that I think that the Hughes/MD/Boeing/MDH (whatever) products I have had the misfortune to operate are the most labour intensive, unreliable, expensive and poorly supported product from any manufacturer. I wouldn't have another one if you gave it to me for free!

I would like to know if the points raised by the GAO report on the INS MD600 purchase were remedied? I found many of them to be equally applicable to the MD500 series, and the majority of those deficiencies had been around for decades, not the short term.

GAO site

Enter MD 600 in report search.

Apologies for the difficulty in accessing this report. Can't get the UBB code to work correctly.



Edited for new software

Thanks for correcting me Hoverbover. You are right. Keep it in trim and that problem will not appear unless the conditions are right.. .. .Not sure if this applies for the whole tailboom, but when the test pilot (do not remember his name)lost the tailboom during testing, he used the collective to keep the attitude under control and get it to the ground without being a lawn dart. He gave a lecture about it where I work and it was pretty interesting.. .. .There is also a rumor running around about several other cracks in different locations other then the one the AD covers. If so, MD is doing a pretty good job covering it up.. .. .Last I heard about the GAO report, the YSAS fixed most of the problems (covered it up).

hover bover . .totaly agree with you . .the 600 can be a handfull at times but does not all performance machines take more handling . .the tail has cracked [but they have stayed on no chopping through tailbooms like other performance types . .. .note to mdhi WHERE IS THE YSAS KITS EVERY BODY IS WAITING FOR..

I don't know about the 600N but I have over 1000Hrs on the 520N and I tell you it's the best helicopter to do Long line slingning. The Notar system is also taking off presure of the pilot shoulders when your landing in dirty confined aerias fifty times a day. It is a lot safer. It is also ez to fly when you get used to it. Not to mention that it can be easely landed with an antitrust failure. But it does need a bit a maintenance.. . The questions you to answer first is where will you operate and what you want to do with it. <img border="0" title="" alt="[Roll Eyes]" src="rolleyes.gif" />

Have you got any photographs, of the work that is being achieved with the MD520

ylhelico, I am not sure how you get that the NOTAR is safer in an anti-thrust failure. The factory will tell you that it is not. They just use the line that it is very unlikely that you will have that problem. Look at all the warnings in the flight manual.

NOTARs have a tail rotor, it is that fancy variable pitch fan inside the tail cone. They also have a mandatory stability system, and a full control system for the slot in back. There are by far more parts to go wrong, more handling problems, more wasted power with the Notar than with a regular tail rotor.. .. .OTOH, the Notar is much better protected so that the danger of a tail strike is almost nil (unless you bang up the rotating mechanism that diverts the air), and the Notar is quite a bit quieter than most tail rotors.. .. .The question is never as simple as "Do you want a Notar or not?" It is always stickier, and involves choices, such as "Do you want a Notar, or an extra passenger?" or "Do you want a Notar, or would you like to launch VFR without a SAS system?". .. .Let the customer decide!

Nick, when you say.... .. .There are by far more parts to go wrong,. .. ....compared to NOTARs, does that parts count include the extra drive shafts, couplers, bearings, and gear boxes of the conventional tailrotor? I do agree with you however that it's really a matter of choice.. .. .Just curious, what is the demonstrated reliablity (service in the field) of NOTAR's compared to conventional tailrotors, and how is this affecting customer satisfaction with the MD600N (or the MD520N or the Explorer for that matter)?

Nick, the SAS system is not a required flight item. Last night I spent four hours in 30 kt winds flying a 520N without one. It wouldn't have made much difference though. <img border="0" title="" alt="[Frown]" src="frown.gif" /> . .. .Flight Safety, our 520N's spend as much or more in maint for tail related items (liners. blades) then our D/E models. The 600's are just hangar queens. With the aft transmission for the fan, hub, 13 blades on the fan, pitch control, thruster control, they did not reduce the number of parts, just the shaft lengths.. .. .And look at what Border Patrol just did. Bought A-Stars instead of the 600N.

nick sorry you are wrong. .the 600 does not have a mandatory stabilisation system in fact it does not have one at all the ysas system that is in the 520 has just been certified now for the 600 but there is none available from mdhi. .. .also you wrote let the customer decide . .. .i did and i am happy with it the 600 is the sports car of helicopters [only upset that mdhi have not got any ysas yet..]. . . . <small>[ 15 March 2002, 09:00: Message edited by: md 600 driver ]</small>

Well I am off base about the mandatory sas for the 600, sorry!. .. .The 520 can swap ends if there is no sas, the 30 knot reagon is not the bad one, high speed is the problem. Chan Morse swaped ends in test, which lead to the sas requirement, if I remember his conversation correctly.. .. .If you look at all the critical parts, the Notar has a bunch more than a tail rotor. How many blades does that screaming fan have, and how many blade grips and bearings? The tail shafting is longer on a tail rotor, granted, with two or so bearing supports. I havn't seen a cutaway of the transmission to count the fan drive section, and compare it to a tail rotor gearbox. The tail rotating can has bearings and a control system, and is there a rudder? All that stuff is important and carries a parts count. In total, I'll bet there are twice the critical parts in a Notar.. .. .The one factor you all didn't challenge is the loss of payload. That small fan eats power, the tail thruster eats power. When we designed Comanche, we found that the power loss of the proposed, not built) Notar was its biggest detractor.. .. .The noise and protected tail are big advantages, so there is not one "right" answer, ever.. .Your collective enthusiasm says plenty, because you are the deciders, in the end!

HeliMark, you're right, in case of complete anti-thrust failure, there is no difference if you have a rotor system or not. But I can assure you that in case of pedal stock, the coenda effect makes it easier and safer to land. . .As I told you all before, if I was flying from helipads to helipads (heliports to heliports)I would prefer a conventionnal tail rotor. But, in dense forest confined aeras or on long line ops, I'd go with the Notar. . . If your tail boom tip goes one feet under water at 100% rpm, would you be able to take off without any damage? That is what I mean bye safety during ops.

ylhelico, I do not agree with you as far as having a stuck pedal. The amount of coanda effect is also affected by the air coming out the slots from the fan. The pitch of the fan is directly connected to the pedals. Lots of air means lots of anti-torque you do not need. And add the thruster equation to that also.. .. .What is worse, is the manual says that if you have a fixed thruster setting "Use powered landing, otherwise it is unlikely that an autorotation can be accomplished.". .. .I am not sure if you have practiced something like a stuck right pedal (say pushed by the instructor 1 1/2") to touchdown. The factory pilot says in that case, touchdown needs to be in the area of 60 kts or greater. <img border="0" title="" alt="[Eek!]" src="eek.gif" /> There is another method of a manuver simular to a power-on auto, making the nose swivel to the left on your decent and touching down at about 10 kts as the nose is swinging right. . .. .There is no question about the safety of the NOTAR as far as the tailboom hitting something verses a tailrotor.. .. .Part of my job is searching for lost hikers in the mountians. I do a lot of confined ops along with one-skid/toe operations. The difference in control between the two is vast. The NOTAR is like a wallowing pig compared to a tailrotor. And we could add the lack of power they have. . .. .Nick, the best we have been able to get the MD people to admit to is anywhere up to 210 hp to run the tail when asking for a bunch of anti-torque. I believe that the most the "E" will grab is around 65 hp. And even though the NOTAR burns around 6-8 gallons more an hour, inorder to carry the same that a 500E will, we have to carry less fuel.

Helimark,. .The fan power varies just like the power to a tail rotor, so there is no one number. Also, the coanda slots are quite efficient, so when the downwash is perfectly aligned with the tailcone, the Notar is not toobad on power. But if the wind is slightly from the tail, the coanda is of almost no use. The original Notar experiments found no yaw control when the wind was 6 knots from the tail, so the can was added to create a tip jet.. .. .One funny thing about power losses is that hover charts in the flight manual are determined in still air, when the main rotor power needs are highest, but when the coanda is most efficient. With any wind or maneuvering, the tip jet becomes the anti-torque device to a fair degree, so the engine power needed goes up, unlike a conventional helo.. .. .For most helos, 1 horsepower lifts about 6 pounds in a hover, so if the Notar eats 25 horsepower more than a tail rotor, that costs 150 pounds of payload. A common tail rotor uses about 5 or 6% of the main rotor power, so a 400 HP helo uses 20 to 24 Horsepower in its tail rotor in a steady hover. If a Notar uses twice that (I think that is a fair estimate), it can lose about 1 passenger as compared to an otherwise identical tail rotor equipped helo.. .. .The protection of a notar is legendary when compared to a tail rotor. If the can in back is bent or jammed by a ground contact, you can get a stuck pedal, but the strike that jams the can would certainly toss a tail rotor into the next county.

Just to update.

The L.A. County Sheriff has grounded all three of their 600's due to cracked bushings on all of the vertical stabilizers (there is four on each bird). What is worse is that the factory has known about this situation for some time, and failed to notify any operators.

Sounds about par for the course!

When I was involved with this product, I used to go to the operator meetings (can't remember what they called them now).

After I had been to a couple, I realised that it was going nowhere - the same issues were discussed time and time again, without any commitment to resolve the problem.

Then I became really alarmed when they brought out an old timer, who told us that all these problems had been around for years, and that fix #15A still hadn't solved the issue, but fix #17B was in the works!:eek:

Virtually every problem was along the same lines.

The MRB problems were absolutely horrific, with virtually every blade being returned to the factory numerous times for warranty work.

I still think the most amusing occurence there was a very contentious dispute over MGB gear scuffing, which resulted in gear rejection at every overhaul. There were some discussions about polishing contact surfaces, but they would have none of that. One of the larger MD Helicopter operators, then informed everyone that he had inadvertently discoverd a legitimate solution for the problem. Prior to every MGB reaching 1000 hours TSO or TSR (warranty limit) he would reject the box for "internal noise". This resulted in the box being torn down for inspection, nothing was ever found, except the gears would be noted to be scuffed beyond limits and replaced free of charge! ;)

MDHS had some very good and very conscientious people working for them. Some really took the comapny's inability to provide acceptable service very personally - they hated it and worked so hard to make it better. It just never seemed to get there though - lack of corporate commitment to the product line.

The new owners have made a sincere attempt to improve the product, service and commitment. The biggest problem is overcoming the years of inattention these products received.

Just to make a comment on something said on the last page by Mr. Helico....

- If you're buying a helicopter to stick its tail in the trees or one foot under water, and then fly away afterwards, maybe you should be driving a pick-up truck instead.

- After 15 years of looking down a longline in everything from 500Ds to Sikorsky 61s, I'm missing the part about how not having a tail rotor could have helped me.

Cyclic Hotline, from what I have seen for the last several years, I disagree on the new company trying to correct the support issue. Well some of it at least.

Yes, when MD took over, the president, vice-president and all the support people came to us and gave us the new better support speech. Also to hear our complaints. Nothing has changed, really. And this tail problem is being paid by the customer. This is the third time that the operators are finding cracking problems that they (MD) have known about prior. Now that is real confidence.

Whoops, let me clarify that.
 

Helimark, let me clarify my statement. Believe me, in no way would I ever endorse any MD product (as stated here and on other forums!);)

I stated that the new management had attempted to improve everything, but if you look to my first comment - this current issue is par for the course! :(

There is a never ending litany of unresolved (or half-assed solutions) to the MD fleet (my experience is limited to the 500).

They are simply the most unreliable, expensive, maintenance intensive, overly complicated, poorly supported product I have ever had the misfortune to operate. The provision of PMA parts has gone some way to reducing costs and remedying the parts supply and availability issues. I would not operate one if you gave it to me for free.

As I once commented on here : My MD500's are (were) the quietest helicopters in the world - because they are always broken down!

ylhelico.

Can I ask what operations you carry out?

I'm just intrigued by your reasoning with regards to confined areas & submerging your tail.

On a personal note I've never had to go in a confined area small enough that my tail rotor was at risk & I certainly have never had my tail rotor threatened by water.

However interesting reading. Have always wondered ref. Notar vs Tail Rotors (After all I've encountered tail rotor problems! :D )

Does the above info. have any relevance to the 900's & 902 aswell?

For the record, I still fly conventional machines & have yet to get my grubby mits on a NOTAR!

after reading all of these posts i wonder if i have a md 600 at all and my friends that have one too they may not have one

there are posts from pprune rs that mentions 500 /520 i thought this thread was about 600 s

i own and fly one i find it a joy to fly ,cheap to maintain,good value for money, reliable, [note it does less time in the maint hanger than some friends i know that have 350/355 /341/ 407 /109/

maybe you should go and fly a 600 then comment every one that has been in mine likes it [i think]

rant over

Like Roofus, I'd also like to know if the problems experienced by some regarding the MD fleet, also apply to the 900 & 902?

To CTD
- A truck, that how we call the notar.

- The difference with the Notar is that when you increase the torque, the anti-thrust increase at the same time because of the increased coanda effect. So you don't need to move the pedals as much as with a conventionnal helo.
Also, with no tail rotor, you're less likely to encounter tail rotor vortex problems.

To Roofus

- For the water: It happened to my partner, he was landed on a beaver dam at 100% and waiting after a passenger when the dam broke down under the weight of the helo. By the time he pulled anought power to hold it up, the tail cone was touching the water.
- During diamonds surveying, we land in swamps 50 times a day and sometime it is somehow dirty. But you always have the choice to land or not. With a notar you just have a bigger selection of areas.:)

md 600 plenum chamber cracks
 

re: md 600 plenum chamber:

cracks found on p/n: 369H3042-11 spray assy water wash. 3 seperate a/c all with approx 3000TT. spray assy cracked radially around plate / wash fitting weld. potential for engine fod is high, replaced with new fittings, have detailed jpeg if so desired.
chopperdr

Also watch out for off field landings in the MD600. The alt. air door does not remain sealed properly with high power settings, allowing dirt, sand and stuff in. Effectively bypassing the filter.

We are restricted from landing off heliport due to FODing 4 engines.

HeliMark,
The U.S. Border Patrol (who operate 10 MD600s) have retrofitted their aircraft with a barrier filter in place of the standard particle seperator. They operator low in desert conditions, probably the worst conditions of any 600 operator, and are seeing a lot less erosion on the compressor blades. They also see an average of 15 degrees lower operating temperatures.

notar fan: is the system you refer to the fdc filter?
chopperdr
p.s. how are our door kits holding up