R44 200ftAGL engine out Autorotation video
I personally think that automotive ignition type switches have no place in the aviation industry. There are too many opportunities for murphy, eg if the key is 180 degrees out, it will still look to be in the correct position
Thread Starter
Fit it with a `proper big round RRPM/ERPM GAUGE......
what surprises me is that the R44 continued to follow the obvious R22 miscalibration. I hate it when the H300 battery voltage is more visible than the R22 RRPM. hard to learn doing autos when you have to resolve millimeters on the needle to get ahead of the aircraft.
I personally think that automotive ignition type switches have no place in the aviation industry.
Certification wise, it seems that it is hard to implement incremental modfication or improvments to an established type.
Yet, the exception:
Airbus helicopter has on the AS350-EC125-H125 made 17 variants (+ 6 conversion kit avaiable)
blade size change, number os seats, dual hydraulic, FADEC, VEMD Avionics, Fuel tank .... it seems that only the center frame and the control rods have remained as designed 50 years ago.
A little anecdote regarding mag switches.
Very early in my career I took over flying a Bell 47 on scenics from a guy that was headed overseas. He told me of a flight where he'd told Dad and his young kid not to touch that particular switch as it would stop the engine running. Dad had to then spend the entire flight stopping thelittle 5hit kid from turning the mags off. I tucked that story in my experience bag and told every kid, that of all those switches in front of you one of them sets off your ejector seat but, I'm not telling you which one! Never once did I have any issues after that. 
Very early in my career I took over flying a Bell 47 on scenics from a guy that was headed overseas. He told me of a flight where he'd told Dad and his young kid not to touch that particular switch as it would stop the engine running. Dad had to then spend the entire flight stopping the
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Pretty much every single engine piston aircraft on the planet uses that same ignition switch. It's probably been around since the 30's. There are exceptions, of course, but they are few and far between. Not something pilots who've only seen the inside of a turbine helicopter might be familiar with. If it was really a problem mechanically or ergonomically it would have been phased out long ago.
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The Tiger Moth has 2 magneto switches outside the cockpit mounted on the fuselage. The right magneto (forward switch) has some low speed ignition retardation capability to allow the starter motor (the person swinging the prop) to easily start the Gypsy Major (the engine). Once started the left magneto (rear switch) is turned on. Magneto checks are done during run-up by momentarily turning off either switch individually, pre-takeoff checks are to ensure both magnetos are on (switches up). Couldn't be simpler.
In this case, it does look like Robinson came up with a new way to complicate things unnecessarily by using a different orientation for installing the same ignition switch. My concern in my post above was that from looking at the pictures megan kindly posted, it does look like the labelling on the switch panel doesn't match that ignition barrel.
Eurocopter also did a bodgy with their unreliable push-button switch panel on their early AS350s. The later toggle switch replacement of this panel is worlds better.
If it was really a problem mechanically or ergonomically it would have been phased out long ago.
Eurocopter also did a bodgy with their unreliable push-button switch panel on their early AS350s. The later toggle switch replacement of this panel is worlds better.
Pretty much every single engine piston aircraft on the planet uses that same ignition switch. It's probably been around since the 30's. There are exceptions, of course, but they are few and far between. Not something pilots who've only seen the inside of a turbine helicopter might be familiar with. If it was really a problem mechanically or ergonomically it would have been phased out long ago.
Don’t get me started.
Someone with a degree thought it was a good idea to put the interior light switch on the door pillar on top of a fuel line....pre 90’s Cessna
Thread Starter
Quote:
The R22 was originally designed witht he leisure or personal business traveler in mind so those RRPM and ERPM gauges were probalby suitable for the purpose of that market segment
Originally Posted by Robbiee
Please elaborate.
The R22 was originally designed witht he leisure or personal business traveler in mind so those RRPM and ERPM gauges were probalby suitable for the purpose of that market segment
Originally Posted by Robbiee
Please elaborate.
originally sold for $40,000 when a new 1979 Cessna 152s and 172s were being delivered at $26,000 and $35,000, respectively.
With respect to the RRPM gauge, one can see how Guimbal did it with the green range taking half the screen, that was better calibrated to the training aircraft market.
From the first line of robinson heliccopter inc history description: Franklin D. Robinson set about designing and building a cost-effective light helicopter targeted at the private individual, small business man.
originally sold for $40,000 when a new 1979 Cessna 152s and 172s were being delivered at $26,000 and $35,000, respectively.
With respect to the RRPM gauge, one can see how Guimbal did it with the green range taking half the screen, that was better calibrated to the training aircraft market.
originally sold for $40,000 when a new 1979 Cessna 152s and 172s were being delivered at $26,000 and $35,000, respectively.
With respect to the RRPM gauge, one can see how Guimbal did it with the green range taking half the screen, that was better calibrated to the training aircraft market.
My concern in my post above was that from looking at the pictures megan kindly posted, it does look like the labelling on the switch panel doesn't match that ignition barrel
Last edited by megan; 15th Mar 2021 at 06:01.
It's a silly switch. Why can't they just have a push to start button (like my car, and every other helicopter I've flown), and a separate spring loaded 3 way switch for testing the magnetos? Then it would be impossible to take off with a magneto inadvertently switched off, no matter how many AR's you "bump" it with.
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As both a pilot and an engineer, I submit that the ergonomics and design of this switch are excellent. It may be esthetically displeasing to some, but it is actually quite a bit safer, simpler and less prone to error than plain old toggle switches. If you don't fly piston single aircraft, fixed or rotary wing, you may not have a full appreciation of this.
- All the functionality you need in one switch. No need for four separate switches (key, left, right, start).
- System state is clear, unambiguous and forced to be sequential.
- Start (or prime) automatically puts you in BOTH.
- Intrinsically resistant to inadvertent movement, no need for "lift to move", switch guards or other mechanical safety features that have to be designed, provisioned, and operated.
In the Raven II, Robinson was actually quite clever by using the traditional start position for prime and providing starter buttons on both the cyclic and collective. They could have left the switch as-is and provided a separate electric priming switch. Instead the design more easily allows for an in-air restart in the unlikely event one has time for such things during the auto, and is more "turbine-like". It would be nice to see this design carry over into new Raven I's and R22's.
As you can see from the photo below, the shaft of the switch is keyed with a notch which prevents it from turning in the panel as the panel hole has a matching stub that goes into that notch. Thus panel legending is no better or worse than a separate legend ring that fits over the switch shaft.
As a rule (there must be a few exceptions) I can't think of modern single engine piston that doesn't use the rotary switch. Things get more complex in piston twins. For instance Cessna twins use plain old toggle switches while Beech twins use two rotary switches.
- All the functionality you need in one switch. No need for four separate switches (key, left, right, start).
- System state is clear, unambiguous and forced to be sequential.
- Start (or prime) automatically puts you in BOTH.
- Intrinsically resistant to inadvertent movement, no need for "lift to move", switch guards or other mechanical safety features that have to be designed, provisioned, and operated.
In the Raven II, Robinson was actually quite clever by using the traditional start position for prime and providing starter buttons on both the cyclic and collective. They could have left the switch as-is and provided a separate electric priming switch. Instead the design more easily allows for an in-air restart in the unlikely event one has time for such things during the auto, and is more "turbine-like". It would be nice to see this design carry over into new Raven I's and R22's.
As you can see from the photo below, the shaft of the switch is keyed with a notch which prevents it from turning in the panel as the panel hole has a matching stub that goes into that notch. Thus panel legending is no better or worse than a separate legend ring that fits over the switch shaft.
As a rule (there must be a few exceptions) I can't think of modern single engine piston that doesn't use the rotary switch. Things get more complex in piston twins. For instance Cessna twins use plain old toggle switches while Beech twins use two rotary switches.
It's a silly switch. Why can't they just have a push to start button (like my car, and every other helicopter I've flown), and a separate spring loaded 3 way switch for testing the magnetos? Then it would be impossible to take off with a magneto inadvertently switched off, no matter how many AR's you "bump" it with.
What has not been mentioned is that if an owner doesn't like the magneto switch installed on their aircraft they have the option to change it legally via an alteration. Have done several. For the aircraft OEM to change that switch it usually doesn't pass the "bang for buck" review on the cost. Those switches are basically bullet-proof provided they are maintained (and used) properly.
Tradition dies hard in aviation. Piston-engine aircraft have been using rotary magneto switches forever. Since the mags can operate without any airframe electrical system at all, manufacturers incorporated a key lock into the switch as an anti-theft device. Putting the key into the switch meant that the manufacturer didn't have to have some other device to disable the ignition.
In the 1960's, when electric starter solenoids became widespread and you no longer had to pull a cable to manually engage the starter, then a button was often installed on the dash, or a spring-loaded "start" position was incorporated into the mag switch. (Some Piper airplanes had a weird one in which you actually had to push the key in while turning it to the "start" position - kind of like an old Volkswagen for those of you old enough to remember.) Some twin-engine fixed-wings used regular ol' toggle switches for the mags, and buttons (or spring-loaded toggles) for activating the starter. Some singles did too - Aeronca Champs had the toggle switches mounted on a panel on the wing root or in a recessed panel on the sidewall between the front and back seats..
Instead of designing special magneto switches for helicopters, r/w manufacturers simply used existing TSO'd fixed-wing switches. Old helicopters, with no locks on the cabin doors and no key needed for the magnetos were ridiculously easy to steal, if you were so inclined and talented. Until recently, I don't think I ever saw a Bell 47 or Hiller 12 with a key-type mag switch. In the 1970's Enstrom finally built their ships with a key-type mags. Robinson, obviously, followed suit. Enstrom put the starter button on the collective. R-22's had the "start" feature built into the mag switch. Later R-44's had a separate starter button (or two). Ahh, consistency in aviation!
Whether the legend for the mags is printed on a ring that surrounds the switch or on the instrument panel itself, I guarantee you that there is a notch and keyway affair in the switch and panel that keeps the barrel from rotating and being misaligned with the legend.
The most obvious explanation for this R-44 crash is this: Even with the key in the "Off" position, one of the mags was ungrounded. We do not know whether this was due to a faulty P-lead coming off the mag, or a defective mag switch. Bottom Line: he was running on one mag. At some point in the takeoff, the connection between the operational mag and 'ground' solidified again (perhaps through vibration). And since the switch was in the "Off" position, what happened was what was supposed to happen: The engine died.
Apparently, the crash happened at 10:00 a.m. Reportedly, the accident flight was the third flight of that day, which meant the first of the one-hour flights was probably around sunrise. I don't know about any of yous guys, but I sometimes experience a "mid-morning slump" in energy and attention levels when the first cup(s) of coffee wears off.. And, being the third flight of the day, our hero probably overlooked some of his usual first-flight-of-the-day procedures...like a mag check, pre-takeoff check...hover-power check, etc. Complacency kills, right? But come on, we see it a lot. And if we're honest, some of us are probably guilty of it too. Me, I'm not saying either way. All's I'm saying that I understand how this probably happened.
In the 1960's, when electric starter solenoids became widespread and you no longer had to pull a cable to manually engage the starter, then a button was often installed on the dash, or a spring-loaded "start" position was incorporated into the mag switch. (Some Piper airplanes had a weird one in which you actually had to push the key in while turning it to the "start" position - kind of like an old Volkswagen for those of you old enough to remember.) Some twin-engine fixed-wings used regular ol' toggle switches for the mags, and buttons (or spring-loaded toggles) for activating the starter. Some singles did too - Aeronca Champs had the toggle switches mounted on a panel on the wing root or in a recessed panel on the sidewall between the front and back seats..
Instead of designing special magneto switches for helicopters, r/w manufacturers simply used existing TSO'd fixed-wing switches. Old helicopters, with no locks on the cabin doors and no key needed for the magnetos were ridiculously easy to steal, if you were so inclined and talented. Until recently, I don't think I ever saw a Bell 47 or Hiller 12 with a key-type mag switch. In the 1970's Enstrom finally built their ships with a key-type mags. Robinson, obviously, followed suit. Enstrom put the starter button on the collective. R-22's had the "start" feature built into the mag switch. Later R-44's had a separate starter button (or two). Ahh, consistency in aviation!
Whether the legend for the mags is printed on a ring that surrounds the switch or on the instrument panel itself, I guarantee you that there is a notch and keyway affair in the switch and panel that keeps the barrel from rotating and being misaligned with the legend.
The most obvious explanation for this R-44 crash is this: Even with the key in the "Off" position, one of the mags was ungrounded. We do not know whether this was due to a faulty P-lead coming off the mag, or a defective mag switch. Bottom Line: he was running on one mag. At some point in the takeoff, the connection between the operational mag and 'ground' solidified again (perhaps through vibration). And since the switch was in the "Off" position, what happened was what was supposed to happen: The engine died.
Apparently, the crash happened at 10:00 a.m. Reportedly, the accident flight was the third flight of that day, which meant the first of the one-hour flights was probably around sunrise. I don't know about any of yous guys, but I sometimes experience a "mid-morning slump" in energy and attention levels when the first cup(s) of coffee wears off.. And, being the third flight of the day, our hero probably overlooked some of his usual first-flight-of-the-day procedures...like a mag check, pre-takeoff check...hover-power check, etc. Complacency kills, right? But come on, we see it a lot. And if we're honest, some of us are probably guilty of it too. Me, I'm not saying either way. All's I'm saying that I understand how this probably happened.
FH1100 is right. Even experienced pilots put the afterburners on the B412 doing what they thought was the hydraulic interlock check, or trying to take off a hospital rooftop pad with only one engine at flight idle.
At least everyone walked away from this one with nothing but a bruised ego (assuming it was a key issue).
At least everyone walked away from this one with nothing but a bruised ego (assuming it was a key issue).
A few basic details here:
https://aviation-safety.net/wikibase/248409
Interesting that the nature of the flight is noted as Private, rather than Commercial?
Inputting the registration into the NTSB accident database returns zero results.
https://aviation-safety.net/wikibase/248409
Interesting that the nature of the flight is noted as Private, rather than Commercial?
Inputting the registration into the NTSB accident database returns zero results.
mjb