Glom
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Are Helicopters Inherently Unreliable?

Thu Mar 05, 2009 8:08 am

If an airline had a dispatch reliability like Bristows of Scatsta have, they'd have gone to the wall even during the dot.com bubble.

It's a daily event. Delays due to a technical problem with choppers. Say what you want about airlines, but a blue carrier doesn't often delay flights due to aircraft technical problems, at not in my experience (of this kind of thing does happen many times, but on an apples and apples comparison, airlines have far, far fewer delays due to technical problems than Bristows).


There are a series of possibilities:

1) Bristows maintenance just suck.
2) The hanger is being shared with some Shetland ponies, who keep eating the rotors.
3) The pilots are sending the aircraft tech for things that airline pilots would gloss over.
4) Dispatch reliability is actually similar, but airlines have more spare aircraft available to compensate.
5) The S92 is an unreliable aircraft.
6) Helicopters in general are unreliable.
 
flypig687
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RE: Are Helicopters Inherently Unreliable?

Thu Mar 05, 2009 6:16 pm

Helicopters are not unreliable aircraft, however they require a lot more maintainence, more often. Not nearly as many moving parts in a plane as in a helicopter.

I know nothing about the company you are talking about, but if i had to guess they probably have a relatively small fleet, used often, and when only a few aircraft go down for maintainence it has a major effect. They might be able to account for this problem by staggering aircraft usage to always have ships up while others are in maintaince.
 
KELPkid
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RE: Are Helicopters Inherently Unreliable?

Thu Mar 05, 2009 7:22 pm

It could just be a symptom of the underlying problem, too...perhaps the dispatch unreliability has something to do with the "toys" not being put away properly at night, or maintenance which should be preventative being exercised in a reactive manner?

You could take any aircraft type in the world, and follow the manufacturer's reccomendations to the "T", and still uncover a problem that is peculiar to a particular operator. Just ask SAS's regional affiliates who were flying Dash 8 Q400's about that...  Wink I'm sure that, given the time and an on-site engineering team, Bombardier could have uncovered what was causing the corrosion in the gear pins in that case...
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Alessandro
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RE: Are Helicopters Inherently Unreliable?

Thu Mar 05, 2009 7:48 pm

Depends which type, the Mil-17 is a workhorse made to last.
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Glom
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RE: Are Helicopters Inherently Unreliable?

Thu Mar 05, 2009 8:13 pm



Quoting KELPkid (Reply 3):
It could just be a symptom of the underlying problem, too...perhaps the dispatch unreliability has something to do with the "toys" not being put away properly at night, or maintenance which should be preventative being exercised in a reactive manner?

Well they are building a new hanger at Scatsta, maybe it is the elements that's causing a problem at the moment. We'll see if dispatch reliability improves once the hanger becomes operational.
 
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larshjort
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RE: Are Helicopters Inherently Unreliable?

Thu Mar 05, 2009 9:01 pm

Helicopters are much more maintenace heavy than regular aircraft due to the fact that everything is shaking in a helicopter.

Quoting KELPkid (Reply 3):

You could take any aircraft type in the world, and follow the manufacturer's reccomendations to the "T", and still uncover a problem that is peculiar to a particular operator. Just ask SAS's regional affiliates who were flying Dash 8 Q400's about that... I'm sure that, given the time and an on-site engineering team, Bombardier could have uncovered what was causing the corrosion in the gear pins in that case...

It wasn't a regional affiliate who had the problems, it was SAS Danmark who had the problems.

/Lars
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2H4
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RE: Are Helicopters Inherently Unreliable?

Thu Mar 05, 2009 10:07 pm



Quoting Glom (Thread starter):
Are Helicopters Inherently Unreliable?

Until we assign a specific definition to the term "unreliable", any replies will tend to be entirely subjective.

And even then, to what do we compare the reliability of helicopters? If we examine dispatch rate and compare it to fixed-wing airliners, it's rather apples & oranges. For example, what does it matter if the airliner has a better dispatch rate, when the airliner cannot complete the mission at hand?

Were such a comparison to be made, it would be more prudent to compare the dispatch rate of helicopters to that of other methods of transport that are able to complete the mission. Blimps, for example. Maybe powered-lift.

It's a bit like saying a glider is more reliable than a Bonanza. While it's undoubtedly true that gliders experience fewer mechanical failures, that statement is of little use, is it not?  Smile

2H4
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tdscanuck
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RE: Are Helicopters Inherently Unreliable?

Fri Mar 06, 2009 3:25 am

"The thing is, helicopters are different from planes. An airplane by it's nature wants to fly, and if not interfered with too strongly by unusual events or by a deliberately incompetent pilot, it will fly. A helicopter does not want to fly. It is maintained in the air by a variety of forces and controls working in opposition to each other, and if there is any disturbance in this delicate balance the helicopter stops flying; immediately and disastrously. There is no such thing as a gliding helicopter. This is why being a helicopter pilot is so different from being an airplane pilot, and why in generality, airplane pilots are open, clear-eyed, buoyant extroverts and helicopter pilots are brooding introspective anticipators of trouble. They know if something bad has not happened it is about to."
- Harry Reasoner Feb 16, 1971
 
bassbonebobo
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RE: Are Helicopters Inherently Unreliable?

Fri Mar 06, 2009 7:04 am



Quoting 2H4 (Reply 7):
It's a bit like saying a glider is more reliable than a Bonanza.

I know an airport bum that claims that Bonanzas make quite reliable gliders (at least his does).  Wink
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KELPkid
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RE: Are Helicopters Inherently Unreliable?

Fri Mar 06, 2009 7:08 am



Quoting Bassbonebobo (Reply 9):
I know an airport bum that claims that Bonanzas make quite reliable gliders (at least his does).

I suppose if you're looking for something that reliably descends... Big grin
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bassbonebobo
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RE: Are Helicopters Inherently Unreliable?

Fri Mar 06, 2009 8:24 am



Quoting KELPkid (Reply 10):
I suppose if you're looking for something that reliably descends...

The way this plane looks I wouldn't be surprised if it was an annual event.  Wow!
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XT6Wagon
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RE: Are Helicopters Inherently Unreliable?

Fri Mar 06, 2009 10:35 am

Its the lack of redundancy in helicopters.

rotor failure = crash
tail rotor failure = crash
gearbox failure = crash

etc etc etc

Conventional planes have nice fixed wings to support the aircraft in the air, leaving failures in the engines or other systems far less nasty. Also much easier and less MX intensive to make sure the wings don't fall off, than a helicopers lifting surfaces.

So... you can bet a helicopter sees ALOT more inspections.
 
Shhpanked
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RE: Are Helicopters Inherently Unreliable?

Fri Mar 06, 2009 11:32 am



Quoting Flypig687 (Reply 1):
Helicopters are not unreliable aircraft, however they require a lot more maintainence, more often. Not nearly as many moving parts in a plane as in a helicopter.

Technically all we need to comply with is the 100 hour and annual inspections, nothing different than the FW guys. That said, where I work, we also use an AAIP based off of the manufacturers maintenance recommendations which just adds a 50 hour inspection to the aforementioned.

Quoting 2H4 (Reply 7):
Until we assign a specific definition to the term "unreliable", any replies will tend to be entirely subjective.

Yeah, for what it's worth in the last six months the helicopter I fly has only gone down once with a mechanical problem. The downwash from a company helicopter slammed the blades which weren't tied down and cracked the swash plate. So wouldn't fall into the category of reliability IMO.
People fly airplanes and pilots fly helicopters.
 
dragon6172
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RE: Are Helicopters Inherently Unreliable?

Fri Mar 06, 2009 12:11 pm



Quoting XT6Wagon (Reply 12):
rotor failure = crash
tail rotor failure = crash
gearbox failure = crash

All depends on the severity... same with an airplane.
wing=crash
vertical tail=crash
engine=crash

An aircraft can glide further than a helo can auto-rotate, so a lot depends on where you are at when your major failure happens.
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metroliner
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RE: Are Helicopters Inherently Unreliable?

Fri Mar 06, 2009 1:05 pm



Quoting Dragon6172 (Reply 14):
wing=crash
vertical tail=crash
engine=crash

Yes, but how often do wings fail in normal usage? Or vertical tails?

Rotor failures are 99% fatal, as are gearbox and tail rotor failures. You can land a plane with bits of wing, vertical tail and engine missing... if you have to!  Smile

(and I won't accept the AA A300 crash in NY as an example...)
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dragon6172
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RE: Are Helicopters Inherently Unreliable?

Fri Mar 06, 2009 2:37 pm



Quoting Metroliner (Reply 15):
Yes, but how often do wings fail in normal usage? Or vertical tails?

About as often as blades fly off of a rotor head?

Quoting Metroliner (Reply 15):
Rotor failures are 99% fatal, as are gearbox and tail rotor failures. You can land a plane with bits of wing, vertical tail and engine missing... if you have to!

Depends on what kind of rotor system failure you are talking about. If you lost a blade it is about as fatal and as likely to happen as losing a wing. If you just clip the tips off... still be able to control your landing probably. Tail rotor failures are far from being 99% fatal (unless you are in a tandem rotor). They are more likely than losing the tail of an aircraft though.

The danger in flying helicopters comes more from the low altitudes they fly at, the fact they do not always land at nice open airports and have to avoid obstacles etc. I will say they are more labor intensive, many more moving parts and things wear out quicker due to the vibrations, etc.
Phrogs Phorever
 
flypig687
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RE: Are Helicopters Inherently Unreliable?

Fri Mar 06, 2009 8:18 pm



Quoting Alessandro (Reply 4):
Depends which type, the Mil-17 is a workhorse made to last.

"Russian Helicopters may be 1/3 the price of American helicopters; however you need to buy 3 Russian helicopters. One to fly and two for parts"
 
UH60FtRucker
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RE: Are Helicopters Inherently Unreliable?

Sat Mar 07, 2009 1:34 am



Quoting XT6Wagon (Reply 11):
tail rotor failure = crash



Quoting Metroliner (Reply 14):
Rotor failures are 99% fatal, as are gearbox and tail rotor failures.

Uhh... not really.

Ever heard of a thing called an autorotation?
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Shhpanked
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RE: Are Helicopters Inherently Unreliable?

Sat Mar 07, 2009 6:20 am



Quoting Metroliner (Reply 14):
Rotor failures are 99% fatal, as are gearbox and tail rotor failures. You can land a plane with bits of wing, vertical tail and engine missing... if you have to!

Like others have said a tail rotor failure is far from being fatal. Roll the throttle off and enter an auto. Simple.

...M/R and T/R transmission do happen but there is usually fair warning giving the pilot enough time to put the aircraft down safely. As for rotor blades flying off the rotor hub? Well I haven't heard of it happening but if it did it would surely be fatal.

Anyways, with ratings in both FW and RW if something were to occur in the air I'd want to be a helicopter not a plane.
People fly airplanes and pilots fly helicopters.
 
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HAWK21M
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RE: Are Helicopters Inherently Unreliable?

Sat Mar 07, 2009 9:09 am



Quoting Glom (Thread starter):
3) The pilots are sending the aircraft tech for things that airline pilots would gloss over.

Any example?
regds
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2H4
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RE: Are Helicopters Inherently Unreliable?

Sat Mar 07, 2009 2:31 pm



Quoting Shhpanked (Reply 18):
Like others have said a tail rotor failure is far from being fatal. Roll the throttle off and enter an auto. Simple.

 checkmark  And sometimes, forego the autorotation entirely and land like an airplane. I watched a Bell 230 do this once.

2H4
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Stealthz
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RE: Are Helicopters Inherently Unreliable?

Sat Mar 07, 2009 2:44 pm



Quoting Glom (Thread starter):
3) The pilots are sending the aircraft tech for things that airline pilots would gloss over.

Given the operating environment I believe they operate in, North Sea, Crap weather, Low alt.
I would if a pilot, and you as a regular passenger should thank them for it!

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