#233681 - 10/13/11 07:04 PM
Re: Video: Cessna 310 Ditching off Hawaii
[Re: Russ]
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Geezer
Registered: 01/21/04
Posts: 5163
Loc: W. WA
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Not necessarily -- If the winds pick up after PONR, it may still be shorter in terms of time and fuel burn, to turn around and fly with the wind to an airfield that is behind you. Not over the ocean! Sue
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#233690 - 10/13/11 07:36 PM
Re: Video: Cessna 310 Ditching off Hawaii
[Re: Susan]
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Geezer
Registered: 06/02/06
Posts: 5357
Loc: SOCAL
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Flying with the wind always increases your ground-speed.
Time-distance/fuel remaining calculations begin shortly after take-off. Normally however, the winds at altitude are planned and if you are iffy on fuel remaining it's a no-go.
When the guys I work with need to take a plane to Hawaii, the question is whether Midway Island is open or are they going through Cold Bay, Alaska direct to Honolulu. The winds are very rarely adequate to support a direct flight from California to Hawaii.
_________________________
Better is the Enemy of Good Enough. Okay, what’s your point??
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#233704 - 10/13/11 10:29 PM
Re: Video: Cessna 310 Ditching off Hawaii
[Re: Doug_Ritter]
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Journeyman
Registered: 05/26/06
Posts: 77
Loc: Cochise Co., AZ
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As a dispatcher, we got upper level wind updates constantly via ACARS (Aircraft Communications Addressing and Reporting System) from various Air Carriers every 7 minutes. Not much info at his altitude.
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#233734 - 10/14/11 03:57 AM
Re: Video: Cessna 310 Ditching off Hawaii
[Re: Russ]
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Stranger
Registered: 10/11/11
Posts: 20
Loc: US
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...So if things look alright 45 min prior and then again as you reach it, but then change for the worse 5 to 10 min later you're committed because now you can't go back because it's closer to continue.... Not necessarily -- If the winds pick up after PONR, it may still be shorter in terms of time and fuel burn, to turn around and fly with the wind to an airfield that is behind you. Modern GPS receivers are very good at doing the math to compute various options. For a relatively slow general aviation aircraft, a change in wind velocity from what was planned can play a huge role in go/no-go decisions mid-flight. IMO (we'll need to wait for the incident report to find out for sure) the reason he put the aircraft in ground effect was to reduce the headwinds at higher altitude. Agreed, I was just illustrating that just because everything is fine up until your PONR it doesn't guarantee a successful crossing it just means you're committed to continuing, and if things change in either direction it will obviously change your PONR as well...but at some point it will be to late to turn back. There could be all kinds of other factors, maybe the engines weren't performing per book spec, maybe the mixture was improperly adjusted either manually or by computer if fuel injected, maybe there was a clog in some or multiple fuel lines either from the probable ferry bladders onboard to the normal tanks, or maybe in the normal fuel system itself, maybe they weren't actually topped off all the way, maybe there was a leak by the fuel caps, maybe the fuel cap wasn't sealed properly, maybe there was a crack in a fuel tank or in a line, maybe the wind was stronger than expected, maybe the flight plan wasn't done properly, maybe, maybe, maybe... There's just too many factors that are unknown, so we wait and hopefully learn what happened to learn from it.
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#233740 - 10/14/11 02:12 PM
Re: Video: Cessna 310 Ditching off Hawaii
[Re: Fred78]
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Newbie
Registered: 10/03/11
Posts: 27
Loc: Floriduh
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Well, I'm of the opinion that the point of no return doesn't guarantee a successful outcome but is your absolute last chance to turn around if things don't add up. After you cross it, you are committed no matter how things change with the fuel/wind etc.., because you won't make it.
So if things look alright 45 min prior and then again as you reach it, but then change for the worse 5 to 10 min later you're committed because now you can't go back because it's closer to continue.
And I bet that's a lonely feeling out over the ocean, by yourself when you know you're gonna get wet and you're 5 plus hours from land.
We don't know what happened, therefore it's impossible to know what he may or may not be guilty of.
Fred -- The bolded part... I did not go into the possibility that AFTER you have DYDD at the 45-minute to PONR point... and then AGAIN at the PONR point... that the wind could suddenly pick up right into your windscreen and ruin all your planning. Here's why: Using your own example above, any pilot (thass you and me, too) should be checking position regularly. So let us posit the very, very, very UNlikely happenstance that 10 minutes after you reach the PONR, suddenly the wind begins to blow right into your front window. Think about it... really. **IF** that semi-instantaneous kamikaze wind is suddenly blowing right in your cockpit at 10 minutes after PONR... ...you say to yourself: "Self? Guess what? There is a sudden and awful headwind. Your new calculation of groundspeed shows you cannot make it to Hawaii!! What to do, what to do? Hmmm... with a tailwind, I can cover a LOT more ground. That means even though I am a tad past PONR, (which was calculated as having the legally required fuel reserve of 45 minutes upon landing at destination) I can turn around and use that TAILWIND to safely get back to try again tomorrow."That is why I did not cover the bolded eventuality. You seem to be saying that in spite of your new calculations showing you are gonna get a wet butt by continuing on INTO the headwind (if there ever was one, but we won't go into that), you gotta do it. I respectfully disagree, bro. You turn your butt around, and use that dirtyrottenevil wind to blow your butt and plane alla way back to California. OK... let us go straight to the sublime... you are 90 miles from Hawaii. Suddenly, outa fargin nowhere, the wind hits 100kts right in your face, and stays there. NOW you cannot make it. That is about how far you have to reach to validate the "sudden, unexpected headwind-as-cause" excuse. The PONR changes (BOTH ways) due to unexpected winds. You can turn around -- with that nice new tailwind -- and fly all the way back. But staying with "get home-itis" will get you wet.
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#233741 - 10/14/11 02:20 PM
Re: Video: Cessna 310 Ditching off Hawaii
[Re: Fred78]
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Newbie
Registered: 10/03/11
Posts: 27
Loc: Floriduh
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...So if things look alright 45 min prior and then again as you reach it, but then change for the worse 5 to 10 min later you're committed because now you can't go back because it's closer to continue.... Not necessarily -- If the winds pick up after PONR, it may still be shorter in terms of time and fuel burn, to turn around and fly with the wind to an airfield that is behind you. Modern GPS receivers are very good at doing the math to compute various options. For a relatively slow general aviation aircraft, a change in wind velocity from what was planned can play a huge role in go/no-go decisions mid-flight. IMO (we'll need to wait for the incident report to find out for sure) the reason he put the aircraft in ground effect was to reduce the headwinds at higher altitude. Agreed, I was just illustrating that just because everything is fine up until your PONR it doesn't guarantee a successful crossing it just means you're committed to continuing, and if things change in either direction it will obviously change your PONR as well...but at some point it will be to late to turn back. There could be all kinds of other factors, maybe the engines weren't performing per book spec, maybe the mixture was improperly adjusted either manually or by computer if fuel injected, maybe there was a clog in some or multiple fuel lines either from the probable ferry bladders onboard to the normal tanks, or maybe in the normal fuel system itself, maybe they weren't actually topped off all the way, maybe there was a leak by the fuel caps, maybe the fuel cap wasn't sealed properly, maybe there was a crack in a fuel tank or in a line, maybe the wind was stronger than expected, maybe the flight plan wasn't done properly, maybe, maybe, maybe... There's just too many factors that are unknown, so we wait and hopefully learn what happened to learn from it. Excellently put, Russ & Fred. I see Russ picked up on the shift of planned vs actual PONR also. And Fred, your whole penultimate (did I actually use that word?) paragraph is Gospel. Any dumping on the guy by me is dependent not upon wind, but my (very possible) "jump to conclusion" about "get home-itis" and (also very possible) non-figuring/ignoring of PONR by the pilot. You have rightly brought up a lot of the myriad little bitsy things that coulda snuck in to possibly explain the unfortunate flight ending. I wonder what the final answer is gonna be.
Edited by Unca_Walt (10/14/11 02:25 PM)
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#233742 - 10/14/11 02:23 PM
Re: Video: Cessna 310 Ditching off Hawaii
[Re: Doug_Ritter]
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Newbie
Registered: 10/03/11
Posts: 27
Loc: Floriduh
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(*snicker*) Youse guys can see Unca Chicken-Liver prolly woulda tried about six times afore he made it. Hey! Click the middle sig line! I am all a-twitter: The Deputy Directory of Counterintelligence and Security Countermeasures in the Pentagon sent me a note: "Ripping good yarn! I especially was impressed by your narrative of naval battles. You created comprehensible pictures of what was undoubtedly chaos on and in the water."DANG!!!
Edited by Unca_Walt (10/14/11 02:30 PM)
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#233744 - 10/14/11 02:58 PM
Re: Video: Cessna 310 Ditching off Hawaii
[Re: Unca_Walt]
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Old Hand
Registered: 06/03/09
Posts: 982
Loc: Norway
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I'd just like to point out that today the quality of weather service is more than adequate to provide info about what kind of head or tailwind to expect. Not with 100% accuracy, but those services ARE plenty good enough that you NEVER should be caugth by surprise by an unexpected headwind.
The needed weather info is there, but is it available in a format, way and form that a particular pilot can relate to? There is still much work to be done when it comes to this kind of weather service.
In a perfect world the winds at your flight level would enter your ground speed calculations automagically. I've seen some proprietary systems where they have this kind of functionality (Jeppesen flight planner, although the user interface for this function was possible one of the worst possible I've ever seen). Proprietary also meant that the system was tied and locked to a particular weather service provider. There's nothing wrong with that particular w.s. provider, but we can't accept that kind of proprietary tie-in.
I'm not a pilot, but I am a weather forecaster that has transformed into something between a geographer and IT consultant. I am working on developing exactly the kind of services and infrastructure for this kind of services for our military.
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#233745 - 10/14/11 03:12 PM
Re: Video: Cessna 310 Ditching off Hawaii
[Re: MostlyHarmless]
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Geezer
Registered: 06/02/06
Posts: 5357
Loc: SOCAL
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about the weather... ...The needed weather info is there, but is it available in a format, way and form that a particular pilot can relate to? There is still much work to be done when it comes to this kind of weather service.... A friend of mine flies with a portable Garmin receiver (similar to the GPSMAP 696) that he sets above the panel on whichever aircraft he's flying. Not only does it do all the air navigation you expect in a receiver of this type, but it also receives XM WX™ Satellite Weather broadcast. If I flew transpac ferry flights for a living, I would definitely invest in a portable nav system, independent of whatever aircraft I was flying. It could/would keep me informed of current events (weather) as well as assist in doing all the navigation and contingency planning.
_________________________
Better is the Enemy of Good Enough. Okay, what’s your point??
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