One Hell Of A Steep Glideslope At Steamboat (KSBS)

Buck Rizvi

Buck Rizvi

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BoulderBuck
It was a beautiful, calm day today so I decided make my first trip ever to Steamboat Springs (KSBS).

I donned my oxygen and flew flight following at 14,500 with the intention of doing a practice approach on the RNAV (GPS) E.

Everything was just dandy until I hit the final approach fix at the required 9,700 feet.

That's when I realized that I needed to drop down at a vertical speed exceeding 1,200 feet per minute to make a visual approach to the runway.

It's more than a bit unnerving to see the tiny postage stamp of a runway at nearly 3,000 AGL when I'm that close.

So I did the sensible thing and went around, joined the normal pattern, and landed on runway 32.

I guess my mistake was I didn't "dive and drive" after the FAF to 8,740 at WAKOR and then again to the MDA immediately after. The "dive and drive" would have certainly had me exceeding 1,500 fpm in order to be at the stepdown altitude before the next waypoint.

Is this situation unique to Steamboat, or are there a lot of other super steep GPS approaches for me to explore :)
 
Amen. IIRC, it’s 13.8 @DBL and then gear out and let the ride begin....
 
Buck Rizvi said:
So I did the sensible thing and went around, joined the normal pattern, and landed on runway 32.

I guess my mistake was I didn't "dive and drive" ...
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No, it's a "Circling" approach. The mistake is expecting to go straight in just because the approach coincides with the runway, imo. At 120 kts, the descent rate looks pretty normal down to circling minimums to me. To go straight in, you'd need to buy some time VFR, by S-turning before getting to the runway. At Aspen, you can square off to a base leg early to accomplish the same.
 
One can always reduce the vertical speed required by reducing their horizontal speed; unpressurized, I dislike more than 1K FPM down.
 
As @dtuuri said, the "E" makes it a circling-only approach. It's not designed to fly straight in from MDA.

I haven't flown the Steamboat approach, but at Aspen, many operators require ceiling and visibility to see the runway from the FAF. From there, idle thrust and all the drag they can muster will allow a straight-in approach. Just about anything beyond that requires maneuvering in the valley.
 
Kenny Phillips said:
One can always reduce the vertical speed required by reducing their horizontal speed; unpressurized, I dislike more than 1K FPM down.
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In order to lose 1900 feet in 2.2 miles at less than 1000 fpm, you'd need to be roughly 60 KIAS or slower with no wind.
 
Buck, what are you flying and how fast on the final approach? At 120 1,000 fpm should work fine to get down 960 feet in 2.4 miles. At 100 knots 700 fpm should be fine. Then you need to circle to land, which is what you did. Anything over 1,000 fpm is no bueno for an approach according to my teachers.
 
We were surprised at Lugano! 11.7% 6.65 deg.
MKx6T4.jpg
 
murphey said:
Steamboat is nuthin' compared to Aspen. You go from 13.7 to 7800 in 11 nm.
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I flew by Aspen last week. Very calm day and I was itchin' to add it to my bucket list. I've heard the landing fees are painful, though. Last time my meager Cherokee Six was in a sea of private jets was at Teterboro. She's still recovering from that ;-)

By comparison, Steamboat Springs airport was sleepy (at least yesterday), super friendly, and run by the City. Relatively cheap gas for a resort town. Stacie, the airport manager, is running a tight ship there!
 
dtuuri said:
No, it's a "Circling" approach. The mistake is expecting to go straight in just because the approach coincides with the runway, imo. At 120 kts, the descent rate looks pretty normal down to circling minimums to me. To go straight in, you'd need to buy some time VFR, by S-turning before getting to the runway. At Aspen, you can square off to a base leg early to accomplish the same.
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Ah, duh! I realize my mistake. I decided on making a visual approach at the FAF straight into runway 32. This GPS-E approach was only meant to set me up to hit the MDA of 8140 for circling, which is essentially what I did by going around and entering the normal pattern. If I was targeting the MDA, I'm sure I would have been just fine. Thanks!
 
PaulS said:
Buck, what are you flying and how fast on the final approach? At 120 1,000 fpm should work fine to get down 960 feet in 2.4 miles. At 100 knots 700 fpm should be fine. Then you need to circle to land, which is what you did. Anything over 1,000 fpm is no bueno for an approach according to my teachers.
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I fly a Cherokee Six 300. My normal approach speed is 100 kts. The mystery is solved: I should have been flying to MDA and made a lap in the pattern, not go directly for the runway from the FAF. Notes for next time! :)
 
Hank S said:
No thanks, I'll circle around a little. The draggier your plane is, the better.
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My circle back around to 32 was just fine and what was called for. My mistake to get greedy and dive for RWY 32 from the FAF.
 
I was scanning the thread titles in the summary view ...

upload_2019-1-11_17-34-19.png

Glideslope ... Buick Riviera.

For a moment there ... :)
 
Yes, terrain can cause a number of steep approaches. While you'll more often find them in the west like you did, they even exist in the "baby" mountains in the east. When I was doing my instrument training in Pennsylvania, the VOR approach at Selinsgrove (next airport over) was a good practice because it had a very steep segment. It taught you to look at how many miles you had between each segment as well as the altitude change, so that you could plan your descent.

In PA we had a lot of airports in valleys or otherwise surrounded by mountains where "brick approaches" were beneficial. I've often theorized that because Piper was originally based in Pennsylvania, they built their aircraft to meet the needs of pilots in the area - which included being able to do steep glide paths. Once they moved to Florida, not so much.

The important thing is knowing the capabilities of your aircraft as well as what you're comfortable with so you can plan how you want to do the final segment of your approach (straight in, circling, etc.) and then be prepared to go around.
 
Buck Rizvi said:
I thought that applies from the final approach fix and, in this case, to the circling MDA of 8140.
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I don't think so, because that would be a slope of
atan((9700-8140)/(2.2+2.4)/1.15/5280) = 3.2 degrees,
which would be consistent with flying the approach as you suggest, with a reasonable glideslope from the FAF to the MDA at the runway end, followed by circling in the pattern to the runway.

The only combination of numbers I can find that gives a slope close to 7.75 degrees is from the last waypoint WAKOR to the runway surface atan((8740-6882)/2.2/1.15/5280) = 7.9 degrees

Screen Shot 2019-01-11 at 10.12.39 PM.png
 
NoHeat said:
I don't think so, because that would be a slope of
atan((9700-8140)/(2.2+2.4)/1.15/5280) = 3.2 degrees,
which would be consistent with flying the approach as you suggest, with a reasonable glideslope from the FAF to the MDA at the runway end, followed by circling in the pattern to the runway.

The only combination of numbers I can find that gives a slope close to 7.75 degrees is from the last waypoint WAKOR to the runway surface atan((8740-6882)/2.2/1.15/5280) = 7.9 degrees
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That 7.75 is indeed measured from WAKOR (note the positioning of the symbol and values), but it is not measured to the runway elevation. It is measured to the TCH elevation, so 6882 + 40 = 6922.
 
RussR said:
That 7.75 is indeed measured from WAKOR (note the positioning of the symbol and values), but it is not measured to the runway elevation. It is measured to the TCH elevation, so 6882 + 40 = 6922.
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I get 5.68 degrees. I believe source is incorrect. It states: WAKOR TO RWY 32: 7.75/40. FAA dutifully charted that. Jeppesen corrected it (even though they seem to be off a tad): EDIT: Jepp rounded 3.36 n.m. to 3.4 n.m.

KSBS.jpg
 
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Frankly, everyone I know ( and me) flys VFR to Steamboat and comes in from HABRO. This past week has been unusually and unseasonably fall-ish with weather. Chickened out on a trip to Leadville - rule of thumb for spam cans along the Front Range....always wickd high winds in the passes during winter so no mountainpasses until spring. Not this winter.

Wait.....yesterday 1/11 weather is back to normal....rats. Too much snow. But the eastern plains deperately needs the moisture.
 
I had flown the approach into Aspen several times in the Pilatus sim before my first time there for real........in a Citation III. When we left Atlanta, the weather was clear and forecasted to stay that way. When we got there it was 4000’ overcast, well above the 2000’ minimums. The sight picture popping out of the clouds was eye opening to say the least. The sim, while pretty good, just doesn’t do it justice.
 
aterpster said:
I get 5.68 degrees. I believe source is incorrect. It states: WAKOR TO RWY 32: 7.75/40. FAA dutifully charted that. Jeppesen corrected it (even though they seem to be off a tad): EDIT: Jepp rounded 3.36 n.m. to 3.4 n.m.

View attachment 70699
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Wally, 5.68 is the angle from the FAF (PEXSA) to the runway threshold at TCH. Since the stepdown fix WAKOR is ABOVE this descent angle, the VDA charted is the one from WAKOR to the runway threshold. FAAO 8260.3D, para 2-6-4e(1)

8740-6922, divided by 2.2 nm gives 826.36 feet per nm, or 7.75 degrees.

I'm not sure what you're saying about source and FAA versus Jepp. Source seems correct and both FAA and Jepp charted 7.75 degrees. Jepp does go the extra step and determines where that higher angle intercepts the PFAF altitude and charts it, in this case at 3.4 nm to the runway.
 
RussR said:
Wally, 5.68 is the angle from the FAF (PEXSA) to the runway threshold at TCH. Since the stepdown fix WAKOR is ABOVE this descent angle, the VDA charted is the one from WAKOR to the runway threshold. FAAO 8260.3D, para 2-6-4e(1)

8740-6922, divided by 2.2 nm gives 826.36 feet per nm, or 7.75 degrees.

I'm not sure what you're saying about source and FAA versus Jepp. Source seems correct and both FAA and Jepp charted 7.75 degrees. Jepp does go the extra step and determines where that higher angle intercepts the PFAF altitude and charts it, in this case at 3.4 nm to the runway.
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Yeah, I got wrapped around the axle. Having said that, no one is going to respect the WAKOR SD if they see the runway earlier. I'm not sure how the pilot is supposed to use this information when the vendors don't make it LNAV+V.
 
Ted DuPuis said:
Yes, terrain can cause a number of steep approaches. While you'll more often find them in the west like you did, they even exist in the "baby" mountains in the east. When I was doing my instrument training in Pennsylvania, the VOR approach at Selinsgrove (next airport over) was a good practice because it had a very steep segment. It taught you to look at how many miles you had between each segment as well as the altitude change, so that you could plan your descent.

In PA we had a lot of airports in valleys or otherwise surrounded by mountains where "brick approaches" were beneficial. I've often theorized that because Piper was originally based in Pennsylvania, they built their aircraft to meet the needs of pilots in the area - which included being able to do steep glide paths. Once they moved to Florida, not so much.

The important thing is knowing the capabilities of your aircraft as well as what you're comfortable with so you can plan how you want to do the final segment of your approach (straight in, circling, etc.) and then be prepared to go around.
Click to expand...

I just did this approach today with a safety pilot in prep of my checkride. It is a fun approach that will keep you on your toes especially with the missed.
 
Buck Rizvi said:
Ah, duh! I realize my mistake. I decided on making a visual approach at the FAF straight into runway 32. This GPS-E approach was only meant to set me up to hit the MDA of 8140 for circling, which is essentially what I did by going around and entering the normal pattern. If I was targeting the MDA, I'm sure I would have been just fine. Thanks!
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Bingo. You can always tell a circling-only approach because it has a letter at the end instead of a runway number, and the only minimums are circling minimums.

There are definitely some fun approaches out that way.
 
It is important to brief all aspects of the approach prior to top of descent. The rate of descent in fpm is given on the approach plate for various ground speeds. Not really one to find out after the faf.

For the prior to top of descent leaving the enroute phase of flight checks I was taught
Whups I Freda (whoops I freda!)

W - weather (i.e get the weather inc atis or the numbers)
HU - heads up (self brief the approach plate)
S - seat belts, tray tables, etc
I - check for ice
F - Fuel on tank(s) with sufficient contents, fuel pump a/r
R - Radios - tuned to navaids and identified, comms on approach and standby on tower etc
E - engine temps and pressures, vacuum etc, mixture
D - directional gyro aligned
A - Altimeter set to airfield QNH

The self brief is slow and measured,e.g
"this will be a RNAV Y 24 into .., the threshold elevation is.. the mda/da is.. the visibility is above minimums, the rod after the faf is.. the missed approach point is ...and the missed approach procedure is.."

hth
 
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Having the banana on your MFD really makes the stepdowns easy, but the math is not that difficult and does not need to be perfect IMHO unless it is in the written. 90 to 100 knots covers about 1 1/2 miles per minute, 120 its 2 miles per minute. So if you need to drop 1,000 feet in 2 miles it's 1000 fpm at 120, or 750 to maybe 850 at 90 to 100.
 
sonopoa said:
The self brief is slow and measured,e.g
"this will be a RNAV Y 24 into .., the threshold elevation is.. the mda/da is.. the visibility is above minimums, the rod after the faf is.. the missed approach point is ...and the missed approach procedure is.."

hth
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"All aspects" of your briefing on this approach would include the ROD from PEXSA to WAKOR and from WAKOR to the TCH. Only the latter is charted (as a descent angle): 7.75 degrees. The descent angle from PEXSA to WAKOR is 3.77 degrees. At 90 knots, ground speed, the RODs would be 600 fpm from PEXSA to WAKOR and 1,240 fpm (as charted by Jeppesen)) from WAKOR to the TCH. If you relied on the chart and set up 1,240 fpm at PEXSA you would cross WAKOR 1,000 feet too low. The charted descent angle is misleading.
 
aterpster said:
"All aspects" of your briefing on this approach would include the ROD from PEXSA to WAKOR and from WAKOR to the TCH.
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agreed

Here is how Jepp charts it
capturenlkkv.png
 
Brief the approach the night before, then you will be more prepared for your VS required on the descent. This is very common at mountain airports.
 
luvflyin said:
Looks like the moral of the story is brief the Approach
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Totally. I've not been practicing enough circling approaches because the LPV and ILS approaches to DA seem more fun.
 
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