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The Official Town Council and Planning Group of Tierrasanta
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Montgomery Field (MYF) Master Plan Update By Eric Germain, President of the Tierrasanta Community Council 6/28/04 At the April meeting of the Tierrasanta Community Council, the TCC President Eric Germain delivered a slide show presentation on Montgomery Field's Master Plan for capital improvements. MYF is important to Tierrasanta because about 120,000-or-so landings per year occur on runways 28R and 28L, and a significant number of these involve a landing route that passes over homes in the southern part of Tierrasanta and the military housing complex at Murphy Canyon. This report examines the improvements planned for MYF and their ramifications to Tierrasanta.
Near-term Improvements to
Montgomery Field: - Relocating the helipad to the northwest corner of MYF (at Balboa Blvd and Kearny Villa Road) - Adding new taxiways and improving existing taxiways - Adding run-up aprons and a blast pad The helipad relocation serves to move helicopter operations to an area of MYF that is slightly more remote from Tierrasanta, which should help reduce (albeit marginally) the noise heard in Tierrasanta. The other improvements should speed the flow of ground traffic at the airport, and thus enable slightly more frequent takeoffs and landings. An increase in traffic probably would marginally increase the noise heard in Tierrasanta. The aggregate impact to Tierrasanta from these improvements probably would be relatively minimal. Long-range Improvements to Montgomery Field: Some of the MYF Master Plan's other recommended improvements, envisioned for later years, potentially would cause a more significant increase to the noise heard by Tierrasantans. Please note that none of the items discussed below are imminent, none have been approved, and none are yet funded. - Runway Strength. One proposed improvement is a re-paving of the main runway, 10L-28R, with a 3-inch layer of asphalt and concrete. While intended as maintenance of the existing surface, this potentially also could serve to make the runway able to support heavier aircraft than are currently permitted by San Diego City Council Resolution 280194 of June 22, 1992. This Resolution, the governing authority that establishes weight limits on aircraft able to operate at MYF, is important because heavier aircraft generally require larger engines, and these typically are noisier. (The current limits are 20,000 pounds for all aircraft, and 12,000 pounds for aircraft with single-wheel landing configuration.) Before the re-paving is done, however, the Airports Director, Ms Tracy Means, has a funded plan to drill core samples of the runways for the purpose of performing scientific analyses of the runway surfaces. The reason for this is to determine the actual weight of aircraft these runways can support in their current state. It is possible the analysis will produce results that indicate weight restrictions must be maintained or reduced, but it's also possible the analysis will suggest larger and heavier aircraft can be supported. Either way, this scientific analysis would have bearing on whether or not to pursue the 3-inch runway re-paving improvement discussed above. If the runway surface is made stronger (if tests show it to be stronger, or if the 3-inch resurfacing makes it stronger), and thus it is able to support greater weight, then this might result in a level of user demand (and/or political pressure) sufficient to cause the City Council to consider changing the rules to allow larger and heavier aircraft to use the runway. But it would take City Council action, a change or cancellation of Resolution 280194, to relax this weight limit, and currently there is no indication any such action is likely to occur. - Runway Length. Runway 28R is the airport’s primary runway, where 85% of the takeoffs and landings occur on this westerly heading (280-deg magnetic). This means 85% of 28R takeoffs are in a direction heading away from Tierrasanta, while 85% of the landings happen with the planes on final approach passing over southern Tierrasanta and Murphy Canyon Military Housing. The other significant proposal is to reduce the displaced threshold of runway 28R by 600 feet: from 1,200 feet down to 600 feet. Currently, airplanes are permitted to use the full 4,600 feet of runway 28R for takeoffs, but they can use only the westernmost 3,400-foot part of runway 28R for landings; this is because the eastern-most 1,200 feet of runway 28R is prohibited for use in landings. Reducing the displaced threshold by 600 feet would extend 28R from 3,400 feet to 4,000 feet for landings only (no change for takeoffs). The current displaced threshold is specifically addressed in City Council Resolution 280194. So here again, the resolution would have to be changed or cancelled in order for the displaced threshold to be changed as the Master Plan recommends, and at present there is no indication such action is likely to occur. But should the runway effectively be lengthened (because more of the existing runway is made available for takeoffs), then the ramification is clear: aircraft that cannot safely land in 3,400 feet of runway cannot use today’s runway 28R, but aircraft that can safely land in 4,000 feet of runway would be able to use the new runway 28R. As above, heavier aircraft tend to have bigger engines, and these tend to be noisier. While it’s not known for sure, this author presumes there is a class of aircraft today (that possibly didn’t exist 12 years ago) which directly might benefit from this runway extension. Such aircraft perhaps would be in the category of small personal, corporate, or regional charter jets, which is the fastest growing segment of civilian aviation. (Having said that, the limiting factor is not so much on landings as it is on takeoffs. This is because heavier aircraft generally require longer runways for takeoff, when planes are loaded with fuel and are at their heaviest. There is no known proposal to lengthen 28R for takeoff.) So why is any of this important? There are two reasons: noise and flight safety. Noise Impacts. IF a stronger runway supports heavier aircraft than currently are permitted by the Council resolution, or IF lengthening the runway to 4,000 feet for landings makes 28R suitable for classes of larger aircraft that today are permitted by the FAA, and IF pressure is brought to bear that causes the City Council to change or cancel the current resolution, THEN it is clear that MYF would be used by these larger and heavier classes of aircraft. This then would only add to the existing traffic supported by the airport, which means the aggregate traffic at MYF would increase. The result of increased traffic (more takeoffs and landings per day) is that the time-averaged Community Noise Equivalent Level (CNEL) impacting the surrounding communities would increase. Bottom line: more traffic equals more noise heard by residents of southern Tierrasanta and Murphy Canyon (and Grantville, and Allied Gardens). But some say that’s not always true. Larger planes tend to be heavier, and usually it's true that heavier planes are noisier, but it is also true that some small jets these days are quieter than their propeller-driven counterparts. You should be the judge: listen for the smaller civilian jet aircraft making landings over your homes and judge for yourself. Do they tend to be quieter (or noisier) than propeller-driven aircraft landing on the same approach path? Flight Safety. Another potential impact from the change in 28R’s displaced threshold is flight safety in poor weather. This change to the displaced threshold means that planes will touch down 600 feet ahead of where they currently are permitted to land. An anticipated ramification of this (resulting from simple trigonometry) is that planes on final approach, using the same glideslope, will fly about 30 feet lower over the homes than they would be with the current threshold. Left unmitigated, this effectively reduces by about 4% the current elevation above homes that planes would fly, which would somewhat reduce flight safety for zero-visibility instrumented approaches. The Master Plan proposes changing the glideslope to a slightly greater angle to maintain altitude above homes on approach to 28R. This action would mitigate the safety issue by restoring the altitude of planes over our homes, but the increased glideslope would be nonstandard and there probably will be some pilots who choose not to fly the steeper approach. Summary. These proposed changes, in aggregate, are potentially (although not certainly) troublesome to Tierrasanta. Adding all of the above produces a worst-case scenario that goes something like this: 1. A lengthened main runway (via a reduced displaced threshold), that also has been reinforced (or that has been certified to permit heavier aircraft via scientific analysis of runway core samples), would put serious pressure on the City Council to relax the 1992 restrictions. 2. The Council would succumb and amend (or rescind) Resolution 280194, and thereby allow larger and heavier aircraft to use Montgomery Field. 3. Among the new classes of airplane allowed to use MYF would be small jets suitable for commuter and business uses. 4. New operations of these larger and heavier aircraft would only be added to the existing mix of traffic, so the overall traffic into and out of MYF would increase. 5. The result of more traffic is clear: the residents of Tierrasanta and Murphy Canyon would be impacted by increased noise. 6. Finally, some pilots will not fly the new glide slope, which means these planes fly at a slightly reduced altitude over our homes. The impact of this is to add a bit more to the overall noise and to marginally reduce the degree of flight safety from what we have today. TCC President Eric Germain is the community's representative to the Airports Advisory Committee (AAC), and the TCC's Area 5 Director, Janet Brown, is the community's representative for MYF noise complaints. The Community Council will continue to monitor MYF improvement plans, and the Council will periodically update the community via noticed hearings and via articles in the TierraTimes. |