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#1
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![]() "Ron Garret" wrote in message ... And there are no other possible ways to hit terrain? None that are caused by use of a handheld GPS for IFR enroute navigation in US controlled airspace. |
#2
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In article t,
"Steven P. McNicoll" wrote: "Ron Garret" wrote in message ... And there are no other possible ways to hit terrain? None that are caused by use of a handheld GPS for IFR enroute navigation in US controlled airspace. What about the following scenario: The pilot is holding the handheld in his hand (imagine that) and drops it. While he is bending down to retrieve it he enters an unusual attitude from which he is unable to recover. Would that not be an accident that is caused (at least in part) by use of a handheld GPS? It would not have occurred if the GPS were not being used. (For the record, I do not believe that the use of a handheld GPS represents a significant risk, and in fact, IFR flight is almost certainly safer with a handheld than without one, all else being equal. But a yoke mount is advisable :-) rg |
#3
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![]() "Ron Garret" wrote in message ... What about the following scenario: The pilot is holding the handheld in his hand (imagine that) and drops it. While he is bending down to retrieve it he enters an unusual attitude from which he is unable to recover. Would that not be an accident that is caused (at least in part) by use of a handheld GPS? No. The handheld GPS didn't cause the aircraft to enter an unrecoverable unusual attitude. It would not have occurred if the GPS were not being used. It wouldn't have occurred if the pilot had been competent. The lesson there is to be competent. |
#4
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In article ,
"Steven P. McNicoll" wrote: "Ron Garret" wrote in message ... What about the following scenario: The pilot is holding the handheld in his hand (imagine that) and drops it. While he is bending down to retrieve it he enters an unusual attitude from which he is unable to recover. Would that not be an accident that is caused (at least in part) by use of a handheld GPS? No. The handheld GPS didn't cause the aircraft to enter an unrecoverable unusual attitude. If an aircraft enters an unusual attitude following an AI failure, most pilots would say that that accident was caused (at least in part) by the AI failure despite the fact that the AI didn't (directly) cause the plane to enter an unusual attitude. But OK, have it your way: the pilot drops the GPS. Being a competent pilot he does not attempt to retrieve it. It bounces around in the turbulence and, unbeknownst to the pilot, it gets wedged under one of the rudder pedals. The airplane spins and crashes turning base to final because the now limited travel on the rudder pedal makes it impossible to adequately compensate for adverse yaw (and the pilot doesn't realize it until it's too late). It would not have occurred if the GPS were not being used. It wouldn't have occurred if the pilot had been competent. The lesson there is to be competent. Most accidents, including this hypothetical one, are the result of long causal chains of events, all of which are collectively necessary for the accident to occur. It is true that the pilot in my first scenario was incompetent, but in a way that would not have manifested itself but for the need to retrieve the GPS from the floor of the plane. (And this, by the way, is why it matters that it's a GPS that was dropped and not, say, a granola bar. The perceived urgency of retrieving a granola bar would probably be less than that of retrieving the GPS.) It's a moot point since I have now provided a scenario involving a competent pilot, but do you have a principled basis for assigning all of the causality to one of many factors in the causal chain, or did you simply choose to make this assignment arbitrarily in order to support your untenable position? rg |
#5
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![]() "Ron Garret" wrote in message ... If an aircraft enters an unusual attitude following an AI failure, most pilots would say that that accident was caused (at least in part) by the AI failure despite the fact that the AI didn't (directly) cause the plane to enter an unusual attitude. I think you're wrong about that. I think most pilots would say that erroneous information provided by a failed AI would be a direct cause of an unusual attitude. Are you a pilot? But OK, have it your way: the pilot drops the GPS. Being a competent pilot he does not attempt to retrieve it. It bounces around in the turbulence and, unbeknownst to the pilot, it gets wedged under one of the rudder pedals. The airplane spins and crashes turning base to final because the now limited travel on the rudder pedal makes it impossible to adequately compensate for adverse yaw (and the pilot doesn't realize it until it's too late). So what you're saying is that loose objects in the cockpit can be hazardous. That may very well be, but that's not the subject of this discussion. Most accidents, including this hypothetical one, are the result of long causal chains of events, all of which are collectively necessary for the accident to occur. It is true that the pilot in my first scenario was incompetent, but in a way that would not have manifested itself but for the need to retrieve the GPS from the floor of the plane. (And this, by the way, is why it matters that it's a GPS that was dropped and not, say, a granola bar. The perceived urgency of retrieving a granola bar would probably be less than that of retrieving the GPS.) Why? The pilot can always ask ATC for navigational assistance, but they can't provide an inflight snack. It's a moot point since I have now provided a scenario involving a competent pilot, but do you have a principled basis for assigning all of the causality to one of many factors in the causal chain, or did you simply choose to make this assignment arbitrarily in order to support your untenable position? My untenable position? It is my position that use of a handheld GPS for IFR enroute navigation in US controlled airspace is without hazard. Note that nobody has identified any hazard from such usage. |
#6
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In article et,
"Steven P. McNicoll" wrote: "Ron Garret" wrote in message ... If an aircraft enters an unusual attitude following an AI failure, most pilots would say that that accident was caused (at least in part) by the AI failure despite the fact that the AI didn't (directly) cause the plane to enter an unusual attitude. I think you're wrong about that. I think most pilots would say that erroneous information provided by a failed AI would be a direct cause of an unusual attitude. I don't really want to quibble over terminology. The fact of the matter is that a failed AI is neither necessary nor sufficient to produce an unusual attitude. (To produce an unusual attitude you must have either erroneous control input, extreme turbulence, or structural failure.) An AI failure is nonetheless considered a risk. Likewise, a failed GPS is neither necessary nor sufficient to produce CFIT. It is nonetheless a risk. The two situations are exactly analogous. They differ only in the degree of risk. Are you a pilot? PPIASEL with just over 500 hours. I fly an SR22. I have also in the past flown IFR in a 182RG/A both with and without a handheld GPS (yoke mounted) and felt a lot safer on the whole when I had it than when I didn't. But OK, have it your way: the pilot drops the GPS. Being a competent pilot he does not attempt to retrieve it. It bounces around in the turbulence and, unbeknownst to the pilot, it gets wedged under one of the rudder pedals. The airplane spins and crashes turning base to final because the now limited travel on the rudder pedal makes it impossible to adequately compensate for adverse yaw (and the pilot doesn't realize it until it's too late). So what you're saying is that loose objects in the cockpit can be hazardous. That may very well be, but that's not the subject of this discussion. It is if the loose object in question was a handheld GPS being used for enroute IFR navigation yada yada yada. Most accidents, including this hypothetical one, are the result of long causal chains of events, all of which are collectively necessary for the accident to occur. It is true that the pilot in my first scenario was incompetent, but in a way that would not have manifested itself but for the need to retrieve the GPS from the floor of the plane. (And this, by the way, is why it matters that it's a GPS that was dropped and not, say, a granola bar. The perceived urgency of retrieving a granola bar would probably be less than that of retrieving the GPS.) Why? The pilot can always ask ATC for navigational assistance, but they can't provide an inflight snack. That's why I hedged with "probably." Different pilots assess situations differently. I can actually envision situations where retrieving a granola bar might have a pretty high priority, but that, as you say, is not the topic under discussion. It's a moot point since I have now provided a scenario involving a competent pilot, but do you have a principled basis for assigning all of the causality to one of many factors in the causal chain, or did you simply choose to make this assignment arbitrarily in order to support your untenable position? My untenable position? It is my position that use of a handheld GPS for IFR enroute navigation in US controlled airspace is without hazard. Note that nobody has identified any hazard from such usage. You can keep insisting that, but the fact of the matter is that I have now described two (or three depending on how you count) potential hazards from such use. So yes, your position that such hazards do not exist is untenable. You can argue that the risks are insignificant (and I would agree, and so, I think, would everyone else) but you can no longer argue that they do not exist without behaving like -- dare I say it? -- an idiot. rg |
#7
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![]() "Ron Garret" wrote in message ... I don't really want to quibble over terminology. The fact of the matter is that a failed AI is neither necessary nor sufficient to produce an unusual attitude. (To produce an unusual attitude you must have either erroneous control input, extreme turbulence, or structural failure.) An AI failure is nonetheless considered a risk. Likewise, a failed GPS is neither necessary nor sufficient to produce CFIT. It is nonetheless a risk. The two situations are exactly analogous. They differ only in the degree of risk. Well, Ron, the fact of the matter is a failed AI is quite sufficient to produce an unusual attitude. PPIASEL with just over 500 hours. I fly an SR22. I have also in the past flown IFR in a 182RG/A both with and without a handheld GPS (yoke mounted) and felt a lot safer on the whole when I had it than when I didn't. Was any of it logged in the US? Was any of it logged outside of MSFS? It is if the loose object in question was a handheld GPS being used for enroute IFR navigation yada yada yada. So you're saying the hazard presented by use of a handheld GPS for enroute IFR navigation in US controlled airspace is loss of rudder control. Is that correct? You can keep insisting that, but the fact of the matter is that I have now described two (or three depending on how you count) potential hazards from such use. So yes, your position that such hazards do not exist is untenable. You can argue that the risks are insignificant (and I would agree, and so, I think, would everyone else) but you can no longer argue that they do not exist without behaving like -- dare I say it? -- an idiot. Right. You said use of a handheld GPS for IFR enroute navigation in US controlled airspace is hazardous because it could compel the pilot to turn off all his other avionics or jam the rudder pedals. And you think me an idiot because I try to explain why that isn't so. You're flying the airways of life with a couple of props feathered. |
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