Hobart accident
Join Date: Mar 2006
Location: Melbourne
Posts: 472
Likes: 0
Received 0 Likes
on
0 Posts
I spent more than a decade on AS350's and there was no issues with hydraulic pumps at any time. Regular belt replacement, maintenance checks carried out and there was never any hydraulic failures at any time in my employers fleet, nor any leased AS350's.
These a/c were mainly used for sling work.
These a/c were mainly used for sling work.
Mark Six, you are nearly correct. Close but no cigar. ADFHS had at least 1 Perhaps 3 damaging (unsure of the categories, but at least 1 was a right off) incidents on hyd off on the BA’s. I went through on BA’s can’t recall if I was on the first or second BA course, we were taught to hover and manoeuvre in the hover hyd off. Accidents happened, thankfully no serious injuries. The Pomms had the legend Keith Champion to learn from, who was an outstanding flight instructor, mentor and champion that learnt his Squirrel craft at ADFHS prior to the World’s ****test cricket team getting BA’s and twist grip throttles.
I digress however, to suggest that the military was beyond reproach is incorrect.
I digress however, to suggest that the military was beyond reproach is incorrect.
Mark Six,
As the comments point out it may be a cultural thing!
No doubt the aircraft does really have a good service record if managed and operated correctly.
I only did about 400 hours on the type and would jump in one again tomorrow.
The history of the ADF use is not as squeaky clean as has been pointed out already -
As the comments point out it may be a cultural thing!
No doubt the aircraft does really have a good service record if managed and operated correctly.
I only did about 400 hours on the type and would jump in one again tomorrow.
The history of the ADF use is not as squeaky clean as has been pointed out already -
Australian Department of Defence Evaluation of the AS 350 BA
In 1997, following a hydraulics-out landing accident, the Royal Australian Air Force (RAAF)
tasked a formal evaluation of the handling qualities of the AS 350 BA with a hydraulic system
malfunction. The goal of the test program was to determine if the flight manual emergency
procedures, approach and landing techniques, and operating limits for the AS 350 BA required
amending due to control forces, handling qualities, or control authority during hydraulic
malfunctions. The result of the assessment was that, during hydraulics-out flight at high gross
weight, the substantially reduced control authority, the considerably increased control free play,
and the greatly increased control forces in all control axes were unacceptable and caused a loss
of control during low-speed flight.
The Department of Defence report (AR-009-993) is approved for public release and in part
concludes that, with respect to hydraulics-out flight:
• the reduced control authority in the collective was unacceptable;
• the high forces in the collective control were unacceptable;
• the reduction in servo authority in cyclic control was unacceptable;
• the cyclic free play was unacceptable;
• the high forces in the longitudinal cyclic control axis were unacceptable; and
• the high forces in the lateral cyclic control axis were unacceptable.
In 1997, following a hydraulics-out landing accident, the Royal Australian Air Force (RAAF)
tasked a formal evaluation of the handling qualities of the AS 350 BA with a hydraulic system
malfunction. The goal of the test program was to determine if the flight manual emergency
procedures, approach and landing techniques, and operating limits for the AS 350 BA required
amending due to control forces, handling qualities, or control authority during hydraulic
malfunctions. The result of the assessment was that, during hydraulics-out flight at high gross
weight, the substantially reduced control authority, the considerably increased control free play,
and the greatly increased control forces in all control axes were unacceptable and caused a loss
of control during low-speed flight.
The Department of Defence report (AR-009-993) is approved for public release and in part
concludes that, with respect to hydraulics-out flight:
• the reduced control authority in the collective was unacceptable;
• the high forces in the collective control were unacceptable;
• the reduction in servo authority in cyclic control was unacceptable;
• the cyclic free play was unacceptable;
• the high forces in the longitudinal cyclic control axis were unacceptable; and
• the high forces in the lateral cyclic control axis were unacceptable.
In the civilian world, at least five AS350 write-offs occurred in the fleet during my time with employers who operated that type, due to hydraulic or engine failures, not including another one which got shot down through no fault other than the multiple bullet holes which caused its demise, plus another AS350 that had a hydraulics failure on take-off that through pure fortune and good luck resulted in a successful landing without a scratch much to the pilots surprise.
...and to conclude on the story of the demise of that AS350 due to bullet holes, the four trigger happy villains that caused said bullet holes were themselves promptly subjected to bullet holes delivered by the good guys, sufficiently to the extent required to cause their permanent demise. Some might say, more than sufficiently so.
Last edited by gulliBell; 21st Dec 2017 at 14:47.
RVDT - that extract for the report looks like someone trying to get funding for a new training helicopter by trashing the reputation of the old one.
It glosses over the words 'high gross weight' and implies the aircraft is unfit for purpose because of the control loads hyd out.
We all know that very little basic training is done at high AUM.
However that information does gel with what I was told in the late 90s - that the Aussies wanted rid of the 350 in that role.
Maybe they should have stuck to cheating at cricket..........
It glosses over the words 'high gross weight' and implies the aircraft is unfit for purpose because of the control loads hyd out.
We all know that very little basic training is done at high AUM.
However that information does gel with what I was told in the late 90s - that the Aussies wanted rid of the 350 in that role.
Maybe they should have stuck to cheating at cricket..........
Originally Posted by [email protected]
...However that information does gel with what I was told in the late 90s - that the Aussies wanted rid of the 350 in that role.
I love the AS350 & have done run on landings with hydraulics off during check rides every 6 months for years now. I must say that even at -20 degrees OAT you sweat your arse off keeping everything under control, as mentioned it can be done & has been done repeatedly but I agree with the ADF report, unacceptable control forces. Unfortunately, as with any manufacturer, money is only invested in R&D when the sales drop off or the FAA forces them to, the AS350 is so good in most other areas that people will keep buying it even if you couldn’t train for hydraulic emergencies. Similar scenario to the old auto to touchdown vs powered recovery technique argument, if the liklihood of having a hydraulic failure is so low that it makes the liklihood of a crash during training the highest risk, should we train all the way to a run on landing or turn the hydraulics back on a few feet from the ground? I think we should keep training to a run on landing, but my daughter would probably agree with Rogers girls that we should not.
Mark Six, you are nearly correct. Close but no cigar. ADFHS had at least 1 Perhaps 3 damaging (unsure of the categories, but at least 1 was a right off) incidents on hyd off on the BA’s. I went through on BA’s can’t recall if I was on the first or second BA course, we were taught to hover and manoeuvre in the hover hyd off. Accidents happened, thankfully no serious injuries. The Pomms had the legend Keith Champion to learn from, who was an outstanding flight instructor, mentor and champion that learnt his Squirrel craft at ADFHS prior to the World’s ****test cricket team getting BA’s and twist grip throttles.
I digress however, to suggest that the military was beyond reproach is incorrect.
I digress however, to suggest that the military was beyond reproach is incorrect.
The basic trainer was the UH-1B, not H. I trained on them, and saw one destroyed in front of me at Wagga when the transmission mounts broke at the bottom of an auto. They were a very durable and forgiving machine but we definitely bent a few of them.
Keith Champion was possibly the best hands-on pilot I've ever seen (and I'm sure he'd agree with me!). We were at the ADFHS (and other places) at the same time.
The AS350 is a fine machine, but why engineer it with such fine tolerances that a simple delay in getting on the ground with a hydraulic problem can cause a fatality?
Make the hyd pump a lot more powerful, have a way of isolating the hyd pressure inside the system like the Bell machines do, and you will do away with the Hydraulic Transparency issues that are a total PITA in the 350.
I have had a scare in a 350 simply from enthusiastic cyclic inputs, which I never encountered in 10,000 Bell hours. And yes, we did have a lot of scrapes in B models during training, but mostly due to the insistence in taking almost every auto to the ground, whereas 99% of the benefits of doing an auto can be achieved in a power termination. But that's another thread.
Make the hyd pump a lot more powerful, have a way of isolating the hyd pressure inside the system like the Bell machines do, and you will do away with the Hydraulic Transparency issues that are a total PITA in the 350.
I have had a scare in a 350 simply from enthusiastic cyclic inputs, which I never encountered in 10,000 Bell hours. And yes, we did have a lot of scrapes in B models during training, but mostly due to the insistence in taking almost every auto to the ground, whereas 99% of the benefits of doing an auto can be achieved in a power termination. But that's another thread.
I'm not sure I understand that. Isolating hydraulic pressure inside the system might result in pressure lock on both sides of the servo power piston, causing it to jam, no? Or do you mean, if the fluid level in the system gets low, isolate the tail rotor servo and preserve any remaining hydraulic pressure for the cyclic servos?
Guest
Posts: n/a
Nubian
Yep, two guys on the controls wasn't good, and yes it was very lucky to have not been an accident.
There was no briefing prior to the event, and me only having 40hrs in the as350 at that time I was pretty green on it.
I discuss it prior to the C and t guys doing a check on me, and I discuss it when I do check rides on others.
My story was a lesson that I learned, and hopefully others can learn from it also.
Yep, two guys on the controls wasn't good, and yes it was very lucky to have not been an accident.
There was no briefing prior to the event, and me only having 40hrs in the as350 at that time I was pretty green on it.
I discuss it prior to the C and t guys doing a check on me, and I discuss it when I do check rides on others.
My story was a lesson that I learned, and hopefully others can learn from it also.
Last edited by Hughesy; 22nd Dec 2017 at 13:03.
Crashes after HYD failure.
I didnt fly the AS350.
I think for ( just about) all A/C, pilots with quite some experience on type, the confidence gets high. ”greatest A/C ever built”. ”No problems, did it a thousand times”.
Still, HYD malfunction on the 350 seems to kill people.
My guess is that the Australian evaluation is spot on, and heliducks post also indicate this.
A system should allow every kind of pilots to survive a malfunction, nut just Biggles on sunny day, but also pilots below avarage skill( yes, there has to be some of these, despite no one ever met one of them) on their not best day.
If it was a Robbie that this kept happening to...?
( I didnt fly the Robbie either, and Im a bit sceptical so).
I think for ( just about) all A/C, pilots with quite some experience on type, the confidence gets high. ”greatest A/C ever built”. ”No problems, did it a thousand times”.
Still, HYD malfunction on the 350 seems to kill people.
My guess is that the Australian evaluation is spot on, and heliducks post also indicate this.
A system should allow every kind of pilots to survive a malfunction, nut just Biggles on sunny day, but also pilots below avarage skill( yes, there has to be some of these, despite no one ever met one of them) on their not best day.
If it was a Robbie that this kept happening to...?
( I didnt fly the Robbie either, and Im a bit sceptical so).
The problem happens when people get complacent or think they know better than the Airbus test pilots and decide to hover the machine hydraulics off, that's when control can be lost very quickly.
I just re-read the article on the Vertical website regarding take offs with the tail rotor hydraulics turned off which is possible in the earlier B3’s, that article is also very critical of the complexity in the system & the functionality of the test sequence for pre-take off & for training. I’m sure it would not be difficult to have a spring loaded switch on the cyclic specifically for training, the functionality of this switch would only be activated by engaging a “ missile” type switch on the console. That way practicing for a hydraulic failure event the pilot could engage the switch which simulates the hydraulic failure, if at any stage during the training sequence things started to go pear shaped all you need to do is release the switch & hydraulics are restored. If you accidentally release the switch you get hydraulic function back, bugger, have to go around & start again.
This doesn’t help the “ light framed” people with man-handling the controls but it would save critical seconds when they’re needed the most.
Heli-ringer is right, follow the manual & all is good but a manual is an administrative control, engineering solutions are better. You can fly around at 60knots all day with the hydraulics off no problem, but get below translational lift speed & you’d need arms the size of Arnie’s legs to keep it under control.
This doesn’t help the “ light framed” people with man-handling the controls but it would save critical seconds when they’re needed the most.
Heli-ringer is right, follow the manual & all is good but a manual is an administrative control, engineering solutions are better. You can fly around at 60knots all day with the hydraulics off no problem, but get below translational lift speed & you’d need arms the size of Arnie’s legs to keep it under control.
So, let's forget whether this is normal operation or training for Emergencies. No need for swiss cheese in this analysis, how come is still acceptable on a contemporary certified helicopter?
I had a BA for 10 years and I don't think there are any real issues with hydraulics ! Yes , things get heavy when you get sub 10 knots and run on is better option if available but zero speed landings are quite possible if no other options . Also the sequence of buttons for hyd off testing are very precise and not too complicated even for me !!
My only issue with the type is the flimsy nature of the cockpit....I would rather hit the ground hard in any other type rather than a 350 ..even Robinsons are safer at that point !!!
My only issue with the type is the flimsy nature of the cockpit....I would rather hit the ground hard in any other type rather than a 350 ..even Robinsons are safer at that point !!!
I once had an issue with a 350B2 that could have been a disaster had altitude not been on my side. At about 2000ft, the hydraulics were isolated on the central collective (after simulating a slider valve seizure) and the student started to slow down too much. As airspeed decayed, he began to lose control in yaw (to the left) so I quickly said "I have control" and started a recovery. As I applied a significant amount of pressure to the right pedal to correct the yaw, my seat slipped back on the rail and I could no longer get enough movement on the yaw pedal to regain control. After a few tense revolutions where I unsuccessfully tried to dive on airspeed to get control back, I shouted at the student to switch the hydraulics back on. (There's only one switch on the standard 350 and it's on the central collective).
I wonder if the seat slipping on the rail could have contributed to this crash?
I wonder if the seat slipping on the rail could have contributed to this crash?
