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Post by codetrucker on Nov 7, 2019 5:20:07 GMT -5
TDZ & FPM GRADING
Okay, I may be off my nut on this one and I suspect you devs have already thought of this, but since there was nothing stated, I offer a "just in case." Also, what I am suggesting may not give a tempting ROI, but it may trigger other creative cogitations. Here goes. Would it not be possible to create a "sweet spot" that would be calculated with the following. I'm not a mathematician, so use my variables and operators loosely. Set optimum landing FPM as a factor of... -> Usual 3-degree descent based on runway slope. -> TDZ per real plates. -> (LengthOfRunway +/- Headwind) -> RequiredSpeedOfAircraftType(Depending on LandingGrossWeight) = TargetTDZAirspeed. Now, with these values it should be possible to create a bell curve of values. Required TDZ would be a percent factor of the runway length with the TDS (Touch Down Spot) being at the top of the bell curve. Deviating away from either side of the curve peak would provide the percent of bonus/penalty for the landing. Here is an example... <> using 15% of the runway length to calculate TDS <> Two pilots - Pilot "A" landed at 800' from threshold @ 210 fpm and Pilot "B" landed 2000 feet from threshold @ 50 fpm... <> Runway = 8000' <> TDS = 1200 feet... optimum from the threshold <> Derived/User-Configured FPM = 190 (optimum) <> Extremes would be 0 fpm and 380 fpm <> 20 points bonus (weighted) available (as an example) where hitting the TDS would be 60% and FPM would count 40%. These values may need to be adjusted. Your call. So, if we calculate the one extreme of the runway (bell curve) = 0 feet from approach end of the runway and the peak of the curve would occur at 1200' then the other "0" on the other end of the curve would be 2400 feet down the tarmac allowing only 5600 feet to safely stop the aircraft. Given the calculated values, it would be easy math to determine the percent of bonus or penalty. Using a similar bell curve to grade FPS should not be complicated. Values outside of the curve would be penalized as a "negative" bonus, if possible. In the Pilot "A" scenario the pilot would be penalized for risking not landing on the runway by touching down too soon (think: wind shear). The Touchdown occurred 400 feet too short. 400/1200=67% * (.60x20 points) = 8 Bonus points. 210-190 = 20 fpm, the inverse percent of (20/190)=89% 89% of the 40% available for FPM = 7 Bonus points. Therefore 6 + 7 = 15 Bonus points for Pilot "A" for this landing. In the Pilot "B" scenario the pilot would be penalized for risking overshooting the runway. The Touchdown occurred 800 feet too long. The inverse of 800/1200=33% * (.60x20 points) = 4 Bonus points. 190-50 = 140 fpm, the percent of (50/190)=26% 26% of the 40% available for FPM = 2 Bonus points. Therefore 4 + 2 = 6 Bonus points for Pilot "B" for this landing. Anyway, here is my offering, such as it is. I hope they may be of service or at least spark other/better ideas. Let me know anything needs clarifying or defining even though I know you can figure it out. Like I said, just in case.
Take care, CT
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Post by peter on Nov 7, 2019 16:59:52 GMT -5
Hi CT,
those are very nice ideas. I am sure Dutch and Travis will consider this.
Cheers, Peter
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Post by Travis on Nov 13, 2019 13:08:40 GMT -5
Knowing where the TDZ is, would be one challenge. (We can know the general parameters of runways, but I've not yet studied the general TDZ layout.) It's possible to know the Vref of the aircraft (if the correct SPEEDCALL entries have been made.) This may not make it for 1.8.2... but we can begin checking certain things. And by the way, I'm Pilot B. Best,
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Post by alaskanflyboy on Nov 13, 2019 16:06:42 GMT -5
Knowing where the TDZ is, would be one challenge. (We can know the general parameters of runways, but I've not yet studied the general TDZ layout.) It's possible to know the Vref of the aircraft (if the correct SPEEDCALL entries have been made.) This may not make it for 1.8.2... but we can begin checking certain things. And by the way, I'm Pilot B. Best, TDZ is typically 3000 feet long on US runways, defined by the sets of bars at the ends of runways with precision markings. Shorter runways have a less defined length, which would be more difficult to work with. Here's more information with good reference links to boot: code7700.com/aim_point_vs_touchdown_point.htmAirlines really don't care much about how far down the runway their aircraft land as they are more concerned with their aircraft stopping before they run out of runway. As far as descent rates at touchdown, I've mentioned elsewhere that there is a fine line as you want passengers to be comfortable but also want to ensure the main gear settles down far enough to engage the weight-on-wheels (aka squat) switches that activate thrust reversers, auto brakes, ground spoilers, steering disconnects, logging of the ACARS "ON" time, and a host of other systems. Landing too soft can delay the aircraft settling to this point. Aircraft that are running light and have sticky struts may fail to engage one or both switches, effectively locking out or failing to activate associated systems.
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Post by DirkDP on Nov 16, 2019 12:33:52 GMT -5
Hi,
Several files generated by the Scenery Scanner have the coordinates of the RWY threshold and heading. So that could be used to determine TD distance from threshold. My VA's flight reports display distance from threshold, but IIRC, there was no way to take into account RWYs with displaced thresholds. Optimal landings are 100-300fpm and TD on the 1st 1/3 of RWY lenght.
Regards, DDP.
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Post by Travis on Nov 16, 2019 13:29:58 GMT -5
I've started liking changing the smooth landing requirements from 0-200fpm to 100-300fpm - but I think I'll do that as an option.
Without looking at the code, I believe this will not be a retroactive change, but if I'm wrong I'll build in a guard so that flights before a certain date always use the old range.
IIRC, MakeRunways' R5.csv includes a displacement value, so we could use that to determine a TDZ. I may want to wait until the FCDU can be used to select both the takeoff and landing runways, so we would know which runway was in play. Sure, we could make a good guess most of the time, but I've seen runway layouts where non-overlapping runways are in odd arrangements, and I'd hate to make a bad guess.
But I also like the idea of getting dinged for floating too much - no matter where or how you land on the runway.
Good ideas all around - thanks Captains!!
Best,
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Post by Travis on Nov 17, 2019 12:55:13 GMT -5
I have the nuts & bolts of the "landing rate" change in place for Alpha 2. I will need to add a guard so older flights won't be affected. (Hint - they would be, and that's not fair.)
But before I go much farther, does anyone feel that each Captain could choose from an small set of "nice landing rates"?
Today there's only one range - "0 to 200".
There's been a suggestion to allow "100 to 300". That's a range I would use.
BUT could a Captain legitimately feel that "200 to 400" is a valid choice?
I personally feel that "300 to 500" would be pushing the envelope, but might there be a legitimate argument made for some Captains using that range??
Best,
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Post by Travis on Nov 17, 2019 12:57:03 GMT -5
I'll add that if a Captain chooses to fly under a different "landing rate", that would also trigger a "floating detector" which we could work on next week. Best,
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Post by Travis on Nov 19, 2019 0:19:58 GMT -5
I've included an option - currently with 4 different variables: (default) 0=0-200fpm, 1=100-300fpm, 2=200-400fpm, 3=200-500fpm. Here's one result on my 'default - really short test flight' using 100-300fpm as a guide. I got 296fpm and a "Nice Landing"! Do know that "Nice Landing" needs more than just landing at a specific rate. Pitch and Bank must be good, no screams in the flight, be close to on-timedon't be late against your Block Time, don't have a Complainer (make lots of announcements!), have a proper landing weight, don't run off the runway, don't crash, don't cancel your flight, etc. Best,
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Post by Travis on Nov 19, 2019 18:09:18 GMT -5
I'm now wondering what to do if you have a small bounce on landing. Currently if your bounce lasts more than 4 seconds, you won't get the PAX Compliment. Should that be reduced below 4 seconds - or should any level of bounce forgo the PAX Compliment?
But should we gauge the "landing speed" (and eventually the "landing spot") on the initial contact or the secondary??
Best,
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Post by alaskanflyboy on Nov 19, 2019 18:56:55 GMT -5
I'm now wondering what to do if you have a small bounce on landing. Currently if your bounce lasts more than 4 seconds, you won't get the PAX Compliment. Should that be reduced below 4 seconds - or should any level of bounce forgo the PAX Compliment? But should we gauge the "landing speed" (and eventually the "landing spot") on the initial contact or the secondary?? Best, For me, any bounced landing is a botched one. More often than not, the plane settles down rather hard after the bounce. So for PAX comments, I'd say bounced landings of any duration should have a more negative element. Most of the flying public knows that a bounce on landing isn't normal and it should affect their confidence in the flight crew.
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Post by DirkDP on Nov 19, 2019 20:07:39 GMT -5
But before I go much farther, does anyone feel that each Captain could choose from an small set of "nice landing rates"? Today there's only one range - "0 to 200". There's been a suggestion to allow "100 to 300". That's a range I would use. BUT could a Captain legitimately feel that "200 to 400" is a valid choice? I personally feel that "300 to 500" would be pushing the envelope, but might there be a legitimate argument made for some Captains using that range?? Best, Hi, It could be set as "airline policy", 100-300 or 200-400 is optimal. Below 50 could be considered as too soft (floating), above 500 (or 600?) too hard. Everything in between acceptable. Regards, Dirk.
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Post by Travis on Nov 20, 2019 13:41:35 GMT -5
For me, any bounced landing is a botched one. More often than not, the plane settles down rather hard after the bounce. So for PAX comments, I'd say bounced landings of any duration should have a more negative element. Most of the flying public knows that a bounce on landing isn't normal and it should affect their confidence in the flight crew. John, The reason I added that last "200-500fpm" range choice is to support an idea to reduce the length of "an acceptable bounce" down to nearly 0. We measure things in "ticks" where there are 18 ticks per second. And we generally allow a second to pass before dinging something as worthy of a penalty. There's a few seconds for a speed penalty, and 500-700 feet for TA and Landing Lights, etc. And when it comes to changes we usually try to allow "the old way of doing things" to be the default setting. I mean if a Captain has been doing things the same way for nearly ten years, we don't want to force them to change. So as it looks now, if you stay with the default setting of 0-200fpm, you'll still have nearly 4 seconds of "acceptable bounce". Change to the next range of 100-200fpm and you can have up to 3 seconds. Change to 200-400fpm, and you can have up to 2 seconds. 200-500fpm allows up to 1 second. I'll try some short flights with the 200-500 range to see how that goes.
I could even see adding an option where No Bounce - even for a tick - is acceptable. Let me know!
Best,
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Post by alaskanflyboy on Nov 20, 2019 19:39:14 GMT -5
Just before I started in flight school years ago, a student pilot stalled one of our Piper Cadets about 10 feet off the runway and taxied back to the ramp with a cracked wing spar. Neither he nor the instructor noticed the aircraft had a noticeable sag as they left the aircraft. Cadets are a stripped-down version of the Warrior, so they have a pronounced dihedral wing and the next student noticed it was rather anhedral.
I could see an option to add hard landings to the existing system that requires inspection before the next flight. I know the Boeing FCOM that comes with the PMDG NGX recommends the aircraft be inspected after a hard landing. I also know from experience as a mechanic that hard landings can do some damage (cracks in wing supports, landing gear attach points, and engine mounts; bent drag braces; popped tires; etc.).
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Post by Travis on Nov 21, 2019 14:17:29 GMT -5
I could see an option to add hard landings to the existing system that requires inspection before the next flight. I know the Boeing FCOM that comes with the PMDG NGX recommends the aircraft be inspected after a hard landing. I also know from experience as a mechanic that hard landings can do some damage (cracks in wing supports, landing gear attach points, and engine mounts; bent drag braces; popped tires; etc.). I've added this to our inspection routine. If a Captain has inspections enabled, this certainly counts as a reason. We randomly call for a minor inspection if you land slightly overweight (an option allows some customization), and a 'medium' inspection if you land severely overweight.
What fpm rate would you judge to be a minimum for an inspection call? I used 1000fpm as a placeholder - that sounds pretty hard to me.
Is there anything else we should consider to call for an inspection? Should smaller aircraft like your Cadet or a Skyhawk be judged at a different (less?) rate than airliners??
I didn't move the option to the airline policy area because I'm coming down with a sinus headache and I would like to get Alpha 2 out this weekend. So my efforts stop here (barring any observances on any test flights). Best regards from your anhedral (old and sagging) F/O.
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