Citation 525B Runway Overrun, Louisville Bowman, 10/7, no fatalities

Doc Holliday said:
So you did the landing performance calculation? Can you post that here? Thanks.
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I used this copy of the manual from the FAA. Wet runway, with no overrun (well, no overrun that's not a par 72) so I added 20%. Maybe you add less, but even at the FAA's 15% for wet runways, you've got no margin. Maybe the plane was very light, and they thought there'd be plenty of pavement. Maybe the boss didn't want to drive a few miles. But he got his shoes wet, that's for sure.
 

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Kenny Phillips said:
I used this copy of the manual from the FAA. Wet runway, with no overrun (well, no overrun that's not a par 72) so I added 20%. Maybe you add less, but even at the FAA's 15% for wet runways, you've got no margin. Maybe the plane was very light, and they thought there'd be plenty of pavement. Maybe the boss didn't want to drive a few miles. But he got his shoes wet, that's for sure.
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So what temp did you use? Zero wind, tail wind or head wind? He flew an hour before landing, so that's about -1000 pounds of fuel (we don't know how much fuel he put on board at departure)
 
At least it appears that it will buff out ... ;)
 
Doc Holliday said:
So what temp did you use? Zero wind, tail wind or head wind? He flew an hour before landing, so that's about -1000 pounds of fuel (we don't know how much fuel he put on board at departure)
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I used local temp at the time (same weather I was having) of 20°C and calm winds (they were light and variable where I was), and guesstimating the landing weight (based on someone who likes to ferry fuel). The "long" runway was out of service.
I was thinking that he could have been very light, and had 20 kts. on the nose, which would have given him a margin of sorts. But then I finally grabbed this from ASN:
METAR KLOU 071407Z 15008KT 2 1/2SM +RA BR BKN009 BKN049 OVC075 21/19 A3003 RMK AO2 P0005 T02060194
Also, from ASN: "ADS-B data indicate that the aircraft ran off the runway at a ground speed of about 55 knots" so not much speed was scraped off on the runway.
Now I'm at a loss as to why he didn't divert. I didn't post all of the landing charts, but there's no scenario that works until you get down to really low landing weights, and then only just. I'm not a fan of only just. And going off at 55 kts ain't close.
Luckily this won't likely affect my insurance rate on a Skyhawk.
 
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Back to key question. Bowman is sooooo close to the Class C "big" airport KSDF. So easy to go there.

And I've landed at Bowman many times - actually started my PPL training there. Why a jet would attempt that runway in those conditions - I don't know.
 
Kenny Phillips said:
Also, from ASN: "ADS-B data indicate that the aircraft ran off the runway at a ground speed of about 55 knots" so not much speed was scraped off on the runway.
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Hydroplaning speed is 9 x sq root of tire pressure, so low tire pressures or high speeds (tailwind, etc.) could have been a big factor.
 
Maybe familiarity with the field and/or aircraft, and bajillions of landings makes one complacent when it comes to 91.103(b) on preflight info on runway lengths…kind of like not doing a W&B on all but the most extreme end of the limits. Not right, but not uncommon.
 
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From ADS-B data:

1000 ft AGL
142 kts, -960 fpm

500 ft AGL
126 kts, -640 fpm

I-264 (0.5 nm from runway)
123 kts, -928 fpm

Crossing approach end of runway 33
121 kts, -1280 fpm

Touchdown
116 kts

Passing runway 6/24 (~1800 ft remaining)
103 kts

8 kt tailwind was noted in post #6

Given runway exit speed of about 60 kts, 40 kts of deceleration in 1800 ft.
 
AquaLand said:
From ADS-B data:

1000 ft AGL
142 kts, -960 fpm

500 ft AGL
126 kts, -640 fpm

I-264 (0.5 nm from runway)
123 kts, -928 fpm

Crossing approach end of runway 33
121 kts, -1280 fpm

Touchdown
116 kts

Passing runway 6/24 (~1800 ft remaining)
103 kts

8 kt tailwind was noted in post #6

Given runway exit speed of about 60 kts, 40 kts of deceleration in 1800 ft.
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So he was Vref + 19 (using a Vref of 108 for 12750) plus a 8kt TW.
 
dtuuri said:
Uh, no. Landing at Vref of 108 w/8 kts of tailwind gives 116 kts @ touchdown.
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I'm not talking touchdown, I'm referring to Vref at threshold which should be 108. Then the GS is increased 8 kts TW for 116. And to add he was 5 knots above Vref (perhaps his Vapp speed)

Vref should happen at 50' above the runway to make published landing numbers. I'm assuming at threshold he was approx 50 feet.

Let's not forget on his PFD and/or MFD he has also a GS readout.

The big point here is he was flying into a runway without enough margin, contaminated and a 8 knot tail wind. We saw the end result.
 
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Doc Holliday said:
I'm not talking touchdown, I'm referring to Vref at threshold which should be 108. Then the GS is increased 8 kts TW for 116. And to add he was 5 knots above Vref (perhaps his Vapp speed)

Vref should happen at 50' above the runway to make published landing numbers. I'm assuming at threshold he was approx 50 feet.

Let's not forget on his PFD and/or MFD he has also a GS readout.

The big point here is he was flying into a runway without enough margin, contaminated and a 8 knot tail wind. We saw the end result.
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Not sure I follow you, but no matter. I'm working backward from this:
AquaLand said:
From ADS-B data:

...

Touchdown
116 kts
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Too fast no matter how you look at it.
 
That’s fast on a wet short runway with tailwind and a heavy airplane.
 
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