RNAV RWY 21 at SMO

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TBalch

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TBalch
It seems like every time I fly this approach, which is not often, I end up way too high at DARTS. Yesterday SoCal cleared me from 7000 to 6000, and very soon after, cleared me for the approach. I had planned a CDFA based on DARTS at 4300, but had to toss that.

I’m guessing they are trying to avoid conflicts with departures from Burbank, so asking for lower probably would be useless.

Anyone out there that’s familiar and has some suggestions?
 
Getting slam dunked into a approach is fairly common, could be traffic, could be radar coverage, just make it work, and if you get too far behind never hesitate to go missed and try again
 
I've heard that joining an approach at a point that is not an IAF, they will most likely keep you high. I didn't quite understand the explanation. But, I've noticed it to be my experience fairly consistently (like 100%). Maybe someone in ATC can chime in and comment.

DARTS is an IF, not an IAF, so that could be why it is. I cannot find an IAF on this approach. Curious... or am I just missing it?

I agree with James331. Be prepared and make it work. I've flown that approach numerous times and always had to hustle down.
 
noahfong didn't miss the IAF. There used to be one on the SMO RNAV 21 chart, but it was way to the southeast of DARTS and so not useful for approaches from most other directions. DARTS is on Victors 186, 459 and 597, and I have received clearances to KSMO via DARTS from V186. That time, I was coming from the east, and was able to cross DARTS at 4200, as per the SMO RNAV 21.

However, when I've come from the west over KBUR, I too have been kept very high by ATC -- "5500 until established" -- and was vectored to join the approach between DARTS and MOVVE which left me way above the glidescope. It took a real dive to get down. For pilots concerned about shock cooling their engines, having to get down that fast is a real concern, and I've talked to one pilot who refused a clearance because it kept him too high for longer than he was willing.

On another occasion, when instructed to remain at or above 5500 until established, I asked for lower and was permitted to descend to 4500 until established. On that occasion, I guessed that there was no traffic coming into or out of KBUR at that moment. And 4500 over DARTS was fine.
 
noahfong said:
I've heard that joining an approach at a point that is not an IAF, they will most likely keep you high. I didn't quite understand the explanation. But, I've noticed it to be my experience fairly consistently (like 100%). Maybe someone in ATC can chime in and comment.

DARTS is an IF, not an IAF, so that could be why it is. I cannot find an IAF on this approach. Curious... or am I just missing it?

I agree with James331. Be prepared and make it work. I've flown that approach numerous times and always had to hustle down.
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Two reasons DARTS is not an IAF:
1. It is on an airway, in which case TERPs does not require an IAF.
2. Radar is required to enter the procedure.
 
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TBalch said:
It seems like every time I fly this approach, which is not often, I end up way too high at DARTS. Yesterday SoCal cleared me from 7000 to 6000, and very soon after, cleared me for the approach. I had planned a CDFA based on DARTS at 4300, but had to toss that.

I’m guessing they are trying to avoid conflicts with departures from Burbank, so asking for lower probably would be useless.

Anyone out there that’s familiar and has some suggestions?
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Sounds like you were coming down V459. MEA is 7000 until over DARTS. That tells a story. Here is the Minimum Vectoring Altitude Map. https://www.faa.gov/air_traffic/fli...tal_products/mva_mia/pdf/SCT_BUR_MVA_2015.pdf

Look at the sector labeled RR 7000. Wrapping around that is the 6000 XXX sector. Follow things from there. The map is centered on the Radar Antenna which is on the Airport at BUR. Best advice I could give is expect and be configured for steep angles of descent if you are arriving via V459.
 
Procedure NA for arrivals at DARTS on V186-597 eastbound, V459-597 northwest bound and on V459 southeast bound.
 
luvflyin said:
Sounds like you were coming down V459. MEA is 7000 until over DARTS. That tells a story. Here is the Minimum Vectoring Altitude Map. https://www.faa.gov/air_traffic/fli...tal_products/mva_mia/pdf/SCT_BUR_MVA_2015.pdf

Look at the sector labeled RR 7000. Wrapping around that is the 6000 XXX sector. Follow things from there. The map is centered on the Radar Antenna which is on the Airport at BUR. Best advice I could give is expect and be configured for steep angles of descent if you are arriving via V459.
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Here's a geo-referenced MVA. The MVA is 6,000 at BERRI and to the NW. Just after BERRI they can descend you to 4,300. Often they don't for workload, or whatever.DARTS.jpg
 
luvflyin said:
Can anyone get those? Link???
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No. I get them because of my work. And, it then takes some work to convert them to be readable by my GIS program.

The FAA said about 5 years ago they would make them available for Jeppesen, etc. Jepp didn't take the deal because the FAA wouldn't commit to keeping them current like Part 95 and 97 IFPs.
 
aterpster said:
No. I get them because of my work. And, it then takes some work to convert them to be readable by my GIS program.

The FAA said about 5 years ago they would make them available for Jeppesen, etc. Jepp didn't take the deal because the FAA wouldn't commit to keeping them current like Part 95 and 97 IFPs.
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I figured as much. Thanks for taking the time to do that
 
They love keeping you high and turning you steeply onto that approach. You just have to be ready for it and slow down the airplane early. It helps to have gear to put down to dirty the plane up. The reasons are both cause of BUR and also to skirt the relatively low LAX Class B in that area, which is just east of the final approach course. Another issue is that the approach was designed for when KSMO had a 5000' runway.
 
TBalch said:
It seems like every time I fly this approach, which is not often, I end up way too high at DARTS. Yesterday SoCal cleared me from 7000 to 6000, and very soon after, cleared me for the approach. I had planned a CDFA based on DARTS at 4300, but had to toss that.

I’m guessing they are trying to avoid conflicts with departures from Burbank, so asking for lower probably would be useless.

Anyone out there that’s familiar and has some suggestions?
Click to expand...
Happened to me several times going into SMO ------- once you pass DARTS it is a "dump and dive" maneuver to get down to the LPV glide slope.
 
@120 knots thats only like 1300 or so fpm to lose 3000 to hit the FAF at altitude I'd just dive and drive it down at 1500+ fpm and slow down at the level off if needed

or

@120 kts to the VDP you get 940 fpm

while it isn't what you planned its not exactly a slam dunk
 
Lon33 said:
shock cooling
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Is this really a thing? I've only seen ancient texts and word of mouth grumpy crusty CFIs saying no more than about 50 or 60 degrees a minute, but what's the scientific engineering based upon that? And has an engine ever failed because of cooling down too fast? Yes I'm aware things expand and contract at different rates, but of all the pressures inside an engine I fail to believe that this is one that could really cause any damage

how is it not just the inverse of when you start up? Obviously when you first start the engine it heats up at more than 50 degrees a minute.. so? it obviously doesn't take two whole minutes for the cylinder head to reach 100 degrees

Actually looks like AVweb recently covered this:
https://www.avweb.com/news/features/Shock-Cooling-Time-to-Kill-the-Myth-230134-1.html

pardon the thread drift, but it's tangentially related, does anyone have any real proof that this is bad for engines?? Like actual teardowns and metallurgical analysis? has anyone's mechanic taken a look at their plane and said "damn Bobby! you must have shock cooled this thing one too many times!"
 
jaybee said:
@120 kts to the VDP you get 940 fpm

while it isn't what you planned its not exactly a slam dunk
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yep, and for the person who's going to have a hard time with a thousand feet per minute, they will not be flyintg the approach at 120.. more like 80.. and at that point the glide rate will be different (less). And for people who can do an approach at 120 knots a thousand feet a minute, while steep, is not unusual or unstable
 
Tantalum said:
yep, and for the person who's going to have a hard time with a thousand feet per minute, they will not be flyintg the approach at 120.. more like 80.. and at that point the glide rate will be different (less). And for people who can do an approach at 120 knots a thousand feet a minute, while steep, is not unusual or unstable
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actually on second look I had calculated for 3.0 degree not the 3.5 on the plate.... still not exactly a slam dunk though
 
Good question about shock cooling. I’ve spoken with three instructors at the same flight school from which I rent a Cirrus SR20 about shock cooling the plane’s engine. One said, in no uncertain terms, that it happens and could damage the engine. Two said shock cooling damage is a myth. All three are experienced instructors. And, again, they instruct in the same school and in the same plane.
 
Lon33 said:
Good question about shock cooling. I’ve spoken with three instructors at the same flight school from which I rent a Cirrus SR20 about shock cooling the plane’s engine. One said, in no uncertain terms, that it happens and could damage the engine. Two said shock cooling damage is a myth. All three are experienced instructors. And, again, they instruct in the same school and in the same plane.
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I've even had the same instructor pull a 180 on this.. twice! So is that a 360?

Instructors know flight dynamics, but I'd love to see an engineer break this down and look at some real data... or even look at 50 or so "spent" engines with different owners polled

Honestly, while there are differences in expansion rates of the metals, that differential is going to be small.. you have to think that the force of compression and combustion, plus all other forces, vibrations, etc. put a much larger stress on the engine. Plus, when you start the engine it is warming at much greater than 50* per minute. I think it can "feel" wrong to go to idle power and descend for 10 minutes.. but the engine is running, combustion is happening, it doesn't care
 
When a lot of people did research after the last round of FAA cylinder debacles, the general consensus is that it is OVERHEATING not OVERCOOLING that is the cause of cylinder failures.
 
Larry in TN said:
What does the airplane's AFM say?
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The Cirrus SR20 POH doesn't say anything at all about shock cooling or about whether pulling the power significantly in order to descend is OK or not. The POH does point out that an Engine Operators and Maintenance Manual is available for purchase; but I don't have one of those.
 
Engines see the most stress during large power changes.

Smoothly advancing the power or reducing the power is prudent.

My A&P and former racecar engine builder/dyno tuner two cents worth.
 
Tantalum said:
I've even had the same instructor pull a 180 on this.. twice! So is that a 360?
Click to expand...

I had an employee tell me that the client "did a complete 360 on me."

When I finished laughing I told her that math wasn't her strong suit and that she meant "did a complete 180." Still didn't get it.

Fortunately her work was always solid.
 
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Ravioli said:
I had an employee tell me that the client "did a complete 360 on me."

When I finished laughing I told her that math wasn't her strong suit and that she meant "did a complete 180." Still didn't get it.

Fortunately her work was always solid.
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Good thing she isn't an airline pilot (very old joke). "Look at the terrible solid line of thunderstorms, left, right, and ahead, as far as you can see. Let's do a 360 and get out of here!"
 
From a practical view on the Santa Monica approach
I always get a "slam dunk" into santa monica too. When flying a plane I don't want to cut the power on, I have my gear down and approach flaps already set and get nice and slow ready to descend. It is still a pretty steep descent, but already being slow at darts makes it a lot easier.

Even IFR, I have the VNAV calculator function dialed up to somewhere on my gps just to give me some reference and help a bit with the situational awareness. When you start to realize you have a lot of air to descend through and not a lot of ground to cover, you start bringing back the power and getting slow. nobody wants to have to cut power on their airplane longer than they have to
 
TheGolfPilot said:
... nobody wants to have to cut power on their airplane longer than they have to
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Especially since the obstacle environment from DARTS to Runway 21 is very hostile for a single-engine airplane.
 
aterpster said:
Especially since the obstacle environment from DARTS to Runway 21 is very hostile for a single-engine airplane.
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Yessireee on that ----- an engine failure on that approach and you are "ess-cee-are-ee-double-u" SCREWED......
 
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