mswmsw

I know there's a lot of smart guys out there, so maybe somebody can answer some questions. I was looking at the KHQM (Hoquiam, WA) ILS approach plate, and had the following questions:

(1) Why are the minimums for the straight-in ILS 24 approach higher than the minimums for the straight-in LOC only approach? (800 and 2 for the ILS and 600 and 3/4 for the LOC only appch)

(2) What do the distance references for the transitions from the ULESS and the SOUPY IAF's refer to? [The notations show 183 degrees (7.3) and LOC (4.5) from ULESS; and 286 degrees (5.9) and LOC (4.5) from SOUPY. ]

Here's the link for the approach plate, if I copied it correctly.

http://204.108.4.16/d-tpp/0801/00889ILD24.PDF

de727ups

No idea about the ILS. Never seen mins like that before.

If you're talking about the 30 inside the D, that means it's a DME fix.

ackeight

The DA and MDA's have something to do with the 500ft tower on 3 DME mile final which is probably only 2 miles from threshold...

For instance: You are on the ILS and at about 3 DME you would be VERY close to the tower on glideslope. However, If you are on the localizer look closely to the profile view. You are only allowed to decend to 840 ft at that tower location (step down fix) then after the tower you can decend to MDA. This is just an obstacle clearance issue.

The second question is just speculation on my part because I've never seen that before but it could be this.

Look at ULESS. It says 183 degrees for 7.3. That is the distance to the localizer course on a 183 Mag Course. The 4.5 could be the distance away from the Localizer directly to it possibly.

ksuav8r

I'm going to agree on the first point that ackeight made. You would be VERY close to the tower if you were to follow the glideslope all the way down. However, with the final stepdown on the localizer located after you pass the tower, then you still have your obstacle clearance.

As for the second question, from ULESS, ackeight is correct in that it is 183 Magnetic course to COXOD and 7.3 nm between the two, however, from there it is another 4.5 nm to LAMMB (the intermediate fix - IF).

Hope that helps.

ackeight

the 4.5 makes sense now. No wonder they put it there instead of over the segment. It's too cramped to put 4.5 from Coxod to lammb. I knew the angles looked different from those two fixes and they both couldn't be 4.5 from the LOC. Thanks for clearing that up for us.

GunnF16

I agree w/ ksuav8r. Its probably a TERPS obstacle clearance calucation that makes you go Missed prior to the obstacle but the step down fix solves the problem on the LOC.

GRDHound

Maybe somebody can help me see the light here. How are ULESS and SOUPY defined other than there DME from HQM? I'm probably missing something obvious but I don't see it.

sparerib11

If you haven't looked at the low altitude enroute chart, ULESS is on V27 on the way from Seattle and SOUPY looks like it is on V204 coming from Olympia.

Bowersbum

I've looked at this plate before. Compare the jepp chart with the NACO chart on the mins for the ILS, there is a very noticable difference.

MoosePileit

Googled, as I've never seen an ILS w/ higher HAT than the no G/S. A 3.27 degree Glideslope would fix the problem if the trees and antennas don't grow or change- then it would be I assume a 200' HAT for the DA.

REPORTS:
ILS/Bowerman Field Update
Kurt Atticott & Reinhardt Jung of Reid Middleton, outlined the Instrument Landing System (ILS) obstruction matter from the initial notice by the FAA describing obstructions on Beacon Hill protruding into the 34:1 approach slope of Runway 24, through aerial photogrammetry undertaken to identify specific problem trees and antennas, to development of a scope of work necessary to remove or mitigate the obstructions from the approach surfaces. Obstacles were identified as:
• Trees that are protruding the glideslope are located on three different property ownerships
• Two antennas located around the City’s water tower are too tall.
• Two additional inner-approach obstructions have been identified at the airport and will be taken care of by the Port.

Mr. Atticott reported the various options to mitigate obstructions and approach procedure:
• In order to restore a 3° glide path on a 34:1 approach slope and have the FAA update approach procedures accordingly, the Port would need to work with property owners to clear the obstructions.
• Another option involves permanently raising the glide slope angle to 3.27° in order to clear all existing Beacon Hill obstructions.

Other options that have been explored, but not considered viable by the FAA are:
• Changing the ILS operations or adding a new ILS to Runway 06.
• A curved or offset approach to Runway 24.
• Eliminate the ILS at Bowerman Field.

Commissioners requested staff to send a letter to the FAA requesting the establishment of an LPV approach to Runway 06 at Bowerman Field.


http://209.85.173.104/search?q=cache...lnk&cd=1&gl=us