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#1
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Primus 1000 FMS brain damage
Today I departed out of RIL as a passenger on a Citation V Ultra being
flown under Part 135. Despite the winds and terrain favoring a departure from runway 26, we departed runway 8. One of the consequences of this was that we needed a 5500 foot ceiling, which we darn near didn't get and we almost got stuck there. When I asked why they departed runway 8 instead of 26 (whose departure minimums require only a 3500 foot ceiling) I was told that the Honeywell Primus 1000 FMS could not be programmed to properly fly the Squat 1 departure (http://204.108.4.16/d-tpp/0801/06741SQUAT.PDF). In particular, the procedure requires that the plane fly to YIRDU intersection before turning towards SQUAT, but the Primus 1000 always interpolates its turns (i.e. it would start turning towards SQUAT slightly before reaching YIRDU), and this cannot be overridden. This all sounded a little farfetched to me. Leaving aside the fact that it's only a 15 degree turn, I don't understand how any IFR-certified GPS (let alone one that they would install on a freakin' jet) could not properly fly a published GPS departure procedure. Can anyone here shed any additional light on this situation? Is this really true, or did I get told a tale? Thanks, rg |
#2
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Primus 1000 FMS brain damage
Ron Garret wrote:
/snip/ When I asked why they departed runway 8 instead of 26 (whose departure minimums require only a 3500 foot ceiling) I was told that the Honeywell Primus 1000 FMS could not be programmed to properly fly the Squat 1 departure (http://204.108.4.16/d-tpp/0801/06741SQUAT.PDF). In particular, the procedure requires that the plane fly to YIRDU intersection before turning towards SQUAT, but the Primus 1000 always interpolates its turns (i.e. it would start turning towards SQUAT slightly before reaching YIRDU), and this cannot be overridden. This all sounded a little farfetched to me. Leaving aside the fact that it's only a 15 degree turn, I don't understand how any IFR-certified GPS (let alone one that they would install on a freakin' jet) could not properly fly a published GPS departure procedure. Can anyone here shed any additional light on this situation? Is this really true, or did I get told a tale? Thanks, rg Ron, I'm not sure what they were trying to tell you, but there are no "fly over" waypoints on this procedure, they are all "fly past", i.e. it's perfectly acceptable (and expected) to anticipate any turns. Yes, any competent FMS can handle this easily (though, I'm not familiar with the Primus 1000 specifically). Which direction was your destination? If it was eastbound, this particular procedure takes you quite a bit out of your way. Perhaps the crew wanted to save gas/flight time by departing 8. That doesn't make much sense, though, if it meant a real possibility of getting stuck there, instead of actually departing. Not only that, but both of the Rwy 8 DP's allow a 400-1 takeoff minimum, assuming you can maintain 320' per NM on the climb out, something I would think a Citation could handle. Happy Flying! Scott Skylane |
#3
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Primus 1000 FMS brain damage
In article ,
Scott Skylane wrote: Ron Garret wrote: /snip/ When I asked why they departed runway 8 instead of 26 (whose departure minimums require only a 3500 foot ceiling) I was told that the Honeywell Primus 1000 FMS could not be programmed to properly fly the Squat 1 departure (http://204.108.4.16/d-tpp/0801/06741SQUAT.PDF). In particular, the procedure requires that the plane fly to YIRDU intersection before turning towards SQUAT, but the Primus 1000 always interpolates its turns (i.e. it would start turning towards SQUAT slightly before reaching YIRDU), and this cannot be overridden. This all sounded a little farfetched to me. Leaving aside the fact that it's only a 15 degree turn, I don't understand how any IFR-certified GPS (let alone one that they would install on a freakin' jet) could not properly fly a published GPS departure procedure. Can anyone here shed any additional light on this situation? Is this really true, or did I get told a tale? Thanks, rg Ron, I'm not sure what they were trying to tell you, but there are no "fly over" waypoints on this procedure, they are all "fly past", i.e. it's perfectly acceptable (and expected) to anticipate any turns. Yes, any competent FMS can handle this easily (though, I'm not familiar with the Primus 1000 specifically). Which direction was your destination? Due west. Burbank. rg |
#4
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Primus 1000 FMS brain damage
Ron Garret wrote:
Which direction was your destination? Due west. Burbank. rg Well, then I am at a complete loss. The appropriate DP in that case, given a Rwy 8 departure, would be the EDUKY ONE. That DP is the only one that *does* contain a "fly over" waypoint, the very thing your pilot said his FMS *couldn't* do! Happy Flying! Scott Skylane |
#5
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Primus 1000 FMS brain damage
Ron Garret wrote:
Today I departed out of RIL as a passenger on a Citation V Ultra being flown under Part 135. Despite the winds and terrain favoring a departure from runway 26, we departed runway 8. One of the consequences of this was that we needed a 5500 foot ceiling, which we darn near didn't get and we almost got stuck there. When I asked why they departed runway 8 instead of 26 (whose departure minimums require only a 3500 foot ceiling) I was told that the Honeywell Primus 1000 FMS could not be programmed to properly fly the Squat 1 departure (http://204.108.4.16/d-tpp/0801/06741SQUAT.PDF). In particular, the procedure requires that the plane fly to YIRDU intersection before turning towards SQUAT, but the Primus 1000 always interpolates its turns (i.e. it would start turning towards SQUAT slightly before reaching YIRDU), and this cannot be overridden. This all sounded a little farfetched to me. Leaving aside the fact that it's only a 15 degree turn, I don't understand how any IFR-certified GPS (let alone one that they would install on a freakin' jet) could not properly fly a published GPS departure procedure. Can anyone here shed any additional light on this situation? Is this really true, or did I get told a tale? Thanks, rg You got a tale, on a number of levels, plus I have to wonder about the competence of that crew. First, an IFR FME (or for that matter a panel mount) must be able to handle both flyover (FO) and fly-by (FB) waypoints. There are two RNAV DPs for Runway 8 and one for 26. There is also a VOR/DME based ODP for Runway 8, but not for 26. So, the basic takeoff minimums apply to the ODP for Runway 8 and to the SQUAT RNAV DP for Runway 26. (26: 3400-3 or standard with a min CG of 360/NM to 10,000. 8: 5500-3 or standard with a min CG of 370/NM to 13,000) The basic Runway 8 takeoff minimums do not apply to the two RNAV DPs for that runway. They each have their own takeoff minimums and CGs. The two RNAV DPs have the mandatory 400-1 requirement even with a CG, whereas the "steam gauge" ODP is standard with its climb gradient. Seems that they were not willing to do any of the three RNAV DPs, thus opted for the steam gauge ODP. Not a good choice at this airport. Runway 26 is downhill and with the use of the SQUAT ONE there is virtually no terrain threat. In fact, engine failure procedures off Runway 26 should be a piece of cake compared to Runway 8. SQUAT is a FB waypoint. The only FO waypoint for any of the three RNAV DPs is USUNE. Squat is speed limited so the turn doesn't occur two early for the AWRAW or EDUKY transitions. There is no speed limit for the JNC transition because there is a very small course change. And, you say they needed a 5500-1 ceiling for Runway 8. True, but only if they couldn't do 370 per mile to 13,000. If that airplane can't do that, it shouldn't be doing IMC charters at an airport like Rifle. Departing on the SQUAT on Runway 26 requires a slightly less climb gradient and only to 10,000 feet, which is far less demanding. I can only speculate: Maybe they don't really know how to do RNAV DPs? Maybe their database was out of date? Maybe they misunderstood the takeoff performance requirements for each runway? Bottom line: Anyone with their act together in an RNAV aircraft would have departed Runway 26. |
#6
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Primus 1000 FMS brain damage
On Sun, 03 Feb 2008 08:44:52 -0800, Sam Spade
wrote: First, an IFR FME (or for that matter a panel mount) must be able to handle both flyover (FO) and fly-by (FB) waypoints. There are two RNAV DPs for Runway 8 and one for 26. I always learn from your posts... G |
#7
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Primus 1000 FMS brain damage
In article ,
Sam Spade wrote: You got a tale, on a number of levels, plus I have to wonder about the competence of that crew. I dunno. I grilled them pretty hard and they seemed to know what they were doing. They didn't get defensive about it or anything. First, an IFR FME (or for that matter a panel mount) must be able to handle both flyover (FO) and fly-by (FB) waypoints. The crew was quite specific that this one could only do FB, except with an upgrade that the company was unwilling to pay for. (I even asked them why don't they just hand-fly the DP, and the answer was that they could, but that the CDI would still direct them according to the FB routing, so that wouldn't actually help.) There is also a VOR/DME based ODP for Runway 8, but not for 26. [xnip] Seems that they were not willing to do any of the three RNAV DPs, thus opted for the steam gauge ODP. Yes, exactly. That is exactly what they said. Not a good choice at this airport. That's what I thought, and that's what they thought. But they said that according to the regs they didn't have a choice. And, you say they needed a 5500-1 ceiling for Runway 8. True, but only if they couldn't do 370 per mile to 13,000. If that airplane can't do that, it shouldn't be doing IMC charters at an airport like Rifle. It can certainly do that with both engines, but with an engine out it's dicey (this, again, according to the crew). I can only speculate: Maybe they don't really know how to do RNAV DPs? Inconceivable. Maybe their database was out of date? Possible, but that's not what they said. Maybe they misunderstood the takeoff performance requirements for each runway? Ditto. Bottom line: Anyone with their act together in an RNAV aircraft would have departed Runway 26. Yeah, that's what I thought. rg |
#8
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Primus 1000 FMS brain damage
All the details aside, there is no RNAV system certified that won't
handle both flyby and flyover waypoints. Such a limited system could not fly any GPS approaches, because they all have a flyover waypoint to begin the missed approach. So, you were being fed some kind of BS. Also, as to Part 135 single-engine contingencies, they could have a different procedure than the ODP for Runway 8, if their company chose to. I will check out the Primus 1000 with some pilots that fly that system. ;-) |
#9
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Primus 1000 FMS brain damage
Did you note that the SQUAT 26 DP doesn't have any flyover waypoints?
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#10
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Primus 1000 FMS brain damage
I got the info.
What the crew told you was about right. That model, as delivered from Cessna, is not RNAV-1 compliant. It requires a couple of hardware mods/additions to become RNAV-1. So, none of the RNAV stuff at RIL was avaiable to them. Not the best configuration to dispatch to RIL in weather conditions. |
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