AS355 TwinStar
Joined: May 2005
Posts: 108
Likes: 0
From: the world
As far as I understand Eurocopter have Given all operatores a choice.
You can either check the damper daily before first flight or you can have the damper removed all together.
It's only taken them over a month to come up with this solution.
They must of had half a dozen monkeys working around the clock on this one
Any opinions on this
You can either check the damper daily before first flight or you can have the damper removed all together.
It's only taken them over a month to come up with this solution.
They must of had half a dozen monkeys working around the clock on this one
Any opinions on this
Joined: Oct 2002
Posts: 1,796
Likes: 1
From: 1 Dunghill Mansions, Putney
The HB350 and HB355 are simply Squirrels/Twin Squirrels produced by Helibras in Brazil (as the Esquilo). Other than customer-specific fits (e.g. for the Brazilian MoD's aircraft), the ships are identical to the various AS350 and AS355 variants.
I/C
I/C
Joined: Dec 2001
Posts: 943
Likes: 0
From: Gold Coast, Queensland
With the single squirrel, the winching is done as with any other helicopter. The stretcher can go either across the back with the seats lifted or fore & aft if the left front seat is removed before winching. Either way is straight forward.
I'm sure the 355 would be the same as the 350.
I'm sure the 355 would be the same as the 350.
Joined: Jun 2005
Posts: 112
Likes: 0
From: North of Eq
I don’t think that the AS 350/355 is wide enough to load a stretcher cross-cabin if you are using full sized people and equipment. Also I doubt that there is a certified cross-cabin installation, but I am sure Vertalop can advise if I am wrong, as he knows more than he is letting on!
There have been a couple of good third party kits for loading a stretcher fore and aft but I don’t think that they are practical to use following a winch operation.
There have been a couple of good third party kits for loading a stretcher fore and aft but I don’t think that they are practical to use following a winch operation.
Joined: Aug 2000
Posts: 121
Likes: 0
From: Australia
Vertalop,
In the many stretcher winches done out of the 355N we never actually brought the gear inside. Instead, we used a quick release belt to secure the stretcher to the step.......
Having said that, every person that we lifted was already deceased, so they never complained.
Cheers
In the many stretcher winches done out of the 355N we never actually brought the gear inside. Instead, we used a quick release belt to secure the stretcher to the step.......
Having said that, every person that we lifted was already deceased, so they never complained.
Cheers
Joined: Feb 2002
Posts: 70
Likes: 0
From: Spain
We do it all the time, acroos the cabin and side door open for a short haul (max 1 minute flight) to the HEMS parked in the vecinity of the rescue site.
Of course a luxury since we ONLY do the rescue itself. The rest is done by the other helicopter.
buen vuelo
Of course a luxury since we ONLY do the rescue itself. The rest is done by the other helicopter.
buen vuelo
Joined: Mar 2002
Posts: 243
Likes: 1
From: West of zero
AS350 / AS355 Tail Rotor heads-up
The aircraft in question is an AS355F1, but since the tail rotor system is identical on all AS350s andAS355s I suggest the lessons from my little episode apply across these types. After engine shut-down, during the rotor run-down, I decided for some trivial reason to play with the pedals: a bit left, a bit right, less than an inch either way. Then I noticed something peculiar: every time I applied any amount of right pedal I would hear some sound from the tail section which in retrospect I would describe as a soft grinding or rubbing sound. The sound would not change in either pitch or volume while applying more or less right pedal, and would immediately stop with neutral or left pedal.
It turned out to be the bearing in the tail rotor pitch change spider (sometimes referred to as the tail rotor swashplate) in the process of self-destruction. The engineer saw an angular difference developing between the rotating and stationary parts as I moved the pedals back and forth. On removal the bearing felt very “gritty” and rough as the races were rotated. The engineer reckoned on another 1-2 hours (!) before complete destruction and possibly seizure. The bearing was about 1100 hours into its 1200-hour life.
The grinding sound was so soft that if I’d kept a little right pedal in during the whole run-down I’m convinced I wouldn’t have noticed anything. Same, of course, for neutral or left pedal. So from now on I shall be gently “walking the pedals” during every rotor run-down; I strongly suggest other AS350/AS355 drivers do the same.
It turned out to be the bearing in the tail rotor pitch change spider (sometimes referred to as the tail rotor swashplate) in the process of self-destruction. The engineer saw an angular difference developing between the rotating and stationary parts as I moved the pedals back and forth. On removal the bearing felt very “gritty” and rough as the races were rotated. The engineer reckoned on another 1-2 hours (!) before complete destruction and possibly seizure. The bearing was about 1100 hours into its 1200-hour life.
The grinding sound was so soft that if I’d kept a little right pedal in during the whole run-down I’m convinced I wouldn’t have noticed anything. Same, of course, for neutral or left pedal. So from now on I shall be gently “walking the pedals” during every rotor run-down; I strongly suggest other AS350/AS355 drivers do the same.
Joined: Sep 2004
Posts: 642
Likes: 2
From: daworld
Buitenzorg,
Well done for chasing this up to find the cause of the noise, but I don't think playing with the pedals during rotor rundown is really a good way of finding any bearing problems. How about checking the bearing on the pre-flight, that way you'll know before you fly if it is OK.
Would be good if you could give us some details as to the calendar time since overhaul, and if all the bulletins had been carried out. When I used to overhaul these things, Eurocopter came out with a number of bulletins to try and improve the reliability. Bearing failure wasn't the problem then, the problem was wear on the bearing housing and wear on the spider because there wasn't enough pinch on the bearing to stop it from rotating in the housing. Your pitch change spider should be at least a -5 or -6, and those dash numbers are from 4 years ago!!!
Well done for chasing this up to find the cause of the noise, but I don't think playing with the pedals during rotor rundown is really a good way of finding any bearing problems. How about checking the bearing on the pre-flight, that way you'll know before you fly if it is OK.
Would be good if you could give us some details as to the calendar time since overhaul, and if all the bulletins had been carried out. When I used to overhaul these things, Eurocopter came out with a number of bulletins to try and improve the reliability. Bearing failure wasn't the problem then, the problem was wear on the bearing housing and wear on the spider because there wasn't enough pinch on the bearing to stop it from rotating in the housing. Your pitch change spider should be at least a -5 or -6, and those dash numbers are from 4 years ago!!!
Joined: Mar 2002
Posts: 243
Likes: 1
From: West of zero
Noooby,
The spider was manufactured new in 1988, completely overhauled in 1999, about 2200 hours TSOH. Originally a -5, modified in 2000 to -6. Bearing that failed was 2 years and almost 1100 hours old. Being a driver, I can’t be bothered to check how many SBs apply to this p/n but the log card indicates 3 having been complied with since overhaul.
I’m intrigued about “checking the bearing on preflight”; how would you go about doing this? The bearing is enclosed within the spider so you can’t see it, and the roughness in the bearing would have to be awful to feel it when rotating the tail rotor by hand. Of course I check for play in the complete assembly and blistered paint (from overheating bearing) but none of these were present. Any other hints?
The spider was manufactured new in 1988, completely overhauled in 1999, about 2200 hours TSOH. Originally a -5, modified in 2000 to -6. Bearing that failed was 2 years and almost 1100 hours old. Being a driver, I can’t be bothered to check how many SBs apply to this p/n but the log card indicates 3 having been complied with since overhaul.
I’m intrigued about “checking the bearing on preflight”; how would you go about doing this? The bearing is enclosed within the spider so you can’t see it, and the roughness in the bearing would have to be awful to feel it when rotating the tail rotor by hand. Of course I check for play in the complete assembly and blistered paint (from overheating bearing) but none of these were present. Any other hints?
Joined: Sep 2004
Posts: 642
Likes: 2
From: daworld
The main problem with the older bearings was binding. With the newer bearings, axial play seems to be the problem. Grab hold of the stationary star, and see if you can move the bearing housing along the stationary star. Heat, as you mentioned, is another give away. They can also sling grease before they give up the ghost. The bearings are sealed, but are installed with grease across the upper and lower surfaces. This grease can melt and get flung out if the bearing gets hot. On the outboard end of the bearing housing, there should be a line of sealant. Make sure this is in good order, otherwise there is a risk of water getting inside the housing. Can't really think of much else. Bearings were always a throw away item during overhaul, but we did check them for play before biffing. Found a couple that had a wee bit of roughness, but only remember one that was kaput, but we couldn't verify it's total time or TSO.
Sounds like you were unlucky to get a bad bearing, and lucky to hear it
Sounds like you were unlucky to get a bad bearing, and lucky to hear it
Joined: Jun 2001
Posts: 506
Likes: 1
From: Europe
Upgraded AS 355N available April 2007 by ECF
The new AS 355 variant designated AS355 NP will be available in April 2007.
This new aircraft has been launched to meet the needs of a wide range of worldwide customers, for corporate transport or several utility missions. It will have enhanced CAT A performance, allowing it to take off at maximum gross weight in various climatic conditions. Improved OEI performances are significantly increasing the payload (+120 kg in HOGE, ISA, SL conditions) for customers operating in specific conditions where performance on one engine is required.
A VEMD system for commonality with the rest of the AS350 family of helicopters has been integrated. The aircraft will be simple to operate both in VFR and IFR missions. Maximum take-off weight with sling load will be increased by 200 kg from presently 2,600 kg to 2,800 kg. This represents an increase of 20 percent of external payload, giving the aircraft real aerial work capabilities. This is achieved by the integration of a new main gearbox, which is derived from the renowned top performer, the AS350 B3, and offers 500 kW of mechanical power.
The AS355 NP will be fitted with two Turbomeca Arrius 1A1 engines.
This new aircraft has been launched to meet the needs of a wide range of worldwide customers, for corporate transport or several utility missions. It will have enhanced CAT A performance, allowing it to take off at maximum gross weight in various climatic conditions. Improved OEI performances are significantly increasing the payload (+120 kg in HOGE, ISA, SL conditions) for customers operating in specific conditions where performance on one engine is required.
A VEMD system for commonality with the rest of the AS350 family of helicopters has been integrated. The aircraft will be simple to operate both in VFR and IFR missions. Maximum take-off weight with sling load will be increased by 200 kg from presently 2,600 kg to 2,800 kg. This represents an increase of 20 percent of external payload, giving the aircraft real aerial work capabilities. This is achieved by the integration of a new main gearbox, which is derived from the renowned top performer, the AS350 B3, and offers 500 kW of mechanical power.
The AS355 NP will be fitted with two Turbomeca Arrius 1A1 engines.
Joined: May 2004
Posts: 394
Likes: 2
From: Aus, Europe & everywhere in between
Sounds like a good aircraft. I personally like the AS355N but any improvements will be welcome.
I just hope the authorities (CASA) in particular see this as a "variant" and not a totally "new" aircraft.
You see, in Australia, as soon as a twin-engine aircraft goes over a MTOW of 2750kg, the requirements for a type rating changes from a 5 hour flight syllabus to a 10 hour syllabus. Let's see!
I just hope the authorities (CASA) in particular see this as a "variant" and not a totally "new" aircraft.
You see, in Australia, as soon as a twin-engine aircraft goes over a MTOW of 2750kg, the requirements for a type rating changes from a 5 hour flight syllabus to a 10 hour syllabus. Let's see!
Joined: May 2004
Posts: 394
Likes: 2
From: Aus, Europe & everywhere in between
Mr Selfish
Sounds like the same scenario but there comes a time when systems enhancements (VEMD, IIDS, etc) differ too much from the "original" product.
Remeber when the B407 was classed under the B206 endorsement? CASA then saw fit to make the 407 a different endorsement altogether. Not a bad idea if you ask me.
I suppose they will look at the new AS355 and decide in good time.
Does anyone know if the physical dimensions of the aircraft differs from the AS355N?
Sounds like the same scenario but there comes a time when systems enhancements (VEMD, IIDS, etc) differ too much from the "original" product.
Remeber when the B407 was classed under the B206 endorsement? CASA then saw fit to make the 407 a different endorsement altogether. Not a bad idea if you ask me.
I suppose they will look at the new AS355 and decide in good time.
Does anyone know if the physical dimensions of the aircraft differs from the AS355N?
Joined: Feb 2006
Posts: 50
Likes: 0
From: In the boot
How many twin squirells do we have in Australia? Not many..count on one hand with some fingers missing. How many operators are interested in a twin squirell in Australia? I venture to say very few indeed...now that the media are all going back to singles.
don't think we need to worry too much about the AS355NP here...its too new for Aussie operators....unless you are wealthy private customer than they seem to go for the A109E or S these days.
don't think we need to worry too much about the AS355NP here...its too new for Aussie operators....unless you are wealthy private customer than they seem to go for the A109E or S these days.
