Posts Tagged ‘faa’

Got PBN?

Wednesday, March 28th, 2012

by Mary Ellen Eagan

Apologies for the somewhat belated post, but here’s a quick recap of the recent UC Davis Noise and Air Quality Symposium: Navigating NextGen, held March 4-6 in Palm Springs, CA.

The focus of much of the discussion at this year’s symposium was implementation of the FAA’s NextGen Program, the early phases of which are now being rolled out across the country.  This blog has discussed NextGen issues before, but I think this was the first conference I’ve attended that attendees were uniformly focused on finding ways to make implementation a success.

The symposium keynote was delivered by Dennis Roberts of the FAA’s ATO. Dennis is responsible for managing FAA’s Optimization of Airspace and Procedures in the Metroplex (OAPM) “metroplex” projects, a systematic, integrated, and accelerated program to implement satellite based navigation in the aviation system.   HMMH is involved in several of the metroplex projects, including the Houston Metroplex, which is on the President’s Federal Infrastructure Dashboard, which was initiated to monitor the pace of DOT efforts to accelerate major infrastructure projects by improving permitting and environmental review processes, and to improve the accountability, transparency, and efficiency of Federal actions. 

Other sessions focused on providing an overview of NextGen technologies and Performance Based Navigation (PBN) terminology, as well as airport experiences implementing and collaborating with FAA on the implementation of procedures at their airports.  The takeaway message from the entire symposium is that there is an urgent need for airports to get involved with NextGen airspace planning – airports understand local issues and provide a critical link between communities and the FAA.  Many airports have also spent years developing noise abatement programs and must be at the table to ensure that airspace planners understand both the spirit and substance of noise abatement.  As active participants in several of these projects, we at HMMH believe that this collaborative approach will be critical to early success of NextGen.

Presentations for the symposium can be found here (click on the presenter’s name).  Next year’s symposium will be held in Orange County, CA.  Please let me know if you have suggestions for topics for discussion.

INM Version 7.0c and Floatplanes in Alaska

Thursday, January 5th, 2012

by Brad Nicholas

If you have not heard, the Federal Aviation Administration (FAA) just released Version 7.0c of its Integrated Noise Model (INM).  This update is almost entirely about database changes, and a lot of them, including:

  • Updated noise information for nineteen aircraft
    • Nine Airbus jets
    • Six props
    • Four helicopters
  • Sixty-eight changes to aircraft substitutions
    • Twenty-two new
    • Thirty-eight modified
    • Eight deleted
  • Eleven new aircraft
    • Five Cessna jets
    • Four Bell helicopters
    • Two single-engine floatplanes
  • Modified arrival profiles for twenty-one aircraft
    • Sixteen Airbus and Boeing jets (updated reverse thrust segment)
    • Five props (added final landing segment)

There are a few other changes, but you can find those in the release notes.  I’m an instructor for HMMH’s INM Training Course so I take an interest in any new releases, but there was something special about this one.  In the list above, I’m fairly confident that the thing that jumps out at everyone is the floatplanes.  Or maybe that’s just me.  Let’s do a little backstory here.

In June of 2007 I was at Willow Lake, Alaska doing noise measurements for a study of floatplane noise.  Willow Lake is just up the road from the now (in)famous city of Wasilla.  Each year, the frozen lake is used as the restart point for the Iditarod dog sled race.  It’s a scenic little lake, surrounded by forest with houses, cabins, and a community center along the shore.  It is also used by floatplanes.

Floatplane Departure, Willow Lake, AK

 The weather for the measurement program was great and the residents around the lake were friendly and helpful.  Folks in Alaska love their airplanes.  It is by far the most aviation-literate population that I have ever met.  Everyone seemed to be a pilot, have been a pilot, or at the bare minimum, have a pilot in the family.  Given the love of airplanes and the low operations levels (approximately twenty operations per day in-season), why was the study necessary?

In short, the floatplanes, particularly the de Havilland DCH-2, are loud and due to the size of the lake and proximity of the houses to the shore, the planes are quite close to residential locations when they are applying full thrust to get off the water.  Here’s a picture of a Beaver taking off from the deck of residence along the shore.

De Havilland DHC-2 Beaver Take-off, Willow Lake, AK

 At full throttle, that radial piston engine and whirling propeller produced maximum levels averaging 112 dBA at this location for northbound departures.  A single northbound DHC-2 departure per day would give a Day Night Average Sound Level (DNL) of 70 dB.  Actual average levels were quite a bit lower due to a much higher percentage of southbound departures and the fact that the lake is frozen most of the year.  Still, after experiencing this firsthand, I was impressed by the tolerance of the locals.
After the measurement program, it was time to model the average annual conditions for our report.  At that time INM 7.0 was the most current version and the DHC-2 was modeled using the GASEPV, a generic single engine piston aircraft with a variable-pitch propeller.  Unfortunately, that aircraft produced levels that were nine to twenty-three decibels too low compared to the measurements, depending on the location along the flight path.  To put twenty-three decibels in perspective, using that aircraft would be the same as using an accurate aircraft, but modeling one two-hundredths of the correct number of operations.
 After no small amount of work and worry, I ended up creating a user-defined aircraft by modifying the GASEPV to have a much longer take-off distance and increased source noise levels.  This produced a reasonable representation of the Beavers operating on the Lake.
Let’s jump back to 2012 and the release of INM 7.0c.  It has a new aircraft, a DHC-2 floatplane.  Let’s see how it compares on the most common departure path at Willow Lake.  The table below includes measured values and the INM 7.0c computed Sound Exposure Level (SEL) and take-off roll distances for the GASEPV (INM 7.0 representation of the DHC-2), my user-defined aircraft, and the new DHC-2FLT.
Item Description Measured GASEPV User-Defined DHC-2FLT
Site 1 SEL (dBA) near start of takeoff





Site 2 SEL (dBA) take-off “roll”





Site 3 SEL (dBA) just after take-off





Site 4 SEL (dBA) after take-off





Take-off Roll (ft)  





Well, nothing hits the measurements exactly at all points, but the user-defined aircraft and the new DHC-2FLT are clearly better than the old substitution.  Of course the user-defined aircraft was developed from precisely this particular set of measurement data so the agreement is not surprising.  The agreement with the new standard INM data is nice to see though.  The development of this data for the new DHC-2FLT will be detailed in a US DOT Volpe National Transportation Systems Center report which is pending publication (see the INM 7.0c release notes).
The discrepancies for the take-off roll portion are not entirely unexpected.  First, the measurements may slightly overstate the SEL by including some taxi noise.  Second, water is a hard reflective surface and the INM will underestimate the levels when the primary reflected path is off the water due to the inclusion of a soft-ground effect.  You can remove this effect for props in the INM, but it would do that at all sites which would throw off the results at Sites 3 and 4 where the soft-ground assumption is more appropriate.  Third, the measurements were of a limited number of aircraft which performed the majority of the operations on this particular lake.  The general fleet may be slightly different.
So there you have it, INM 7.0c is out and it has two new floatplanes.  This may not matter to most folks, but I can remember a few months back 2007 when this would have made my life a lot easier.

A Better Way to Compare Aircraft Noise and Emissions?

Wednesday, April 6th, 2011

by Nick Miller

The World Health Organization (WHO) has recently published “Burden of disease from environmental noise, Quantification of healthy life years lost in Europe.” The title sparked my interest because there is an on-going effort in the U.S. to quantify and compare the relative adverse effects on society caused by aviation noise and aviation produced air pollutants. For the primary air pollutants, current U.S. work translates benefits of reductions to such things as reductions in premature mortality and in chronic bronchitis, to which dollar benefits are assigned. For noise, the Noise Depreciation Index (NDI) reveals how many dollars in housing prices are gained by reducing noise. 

I’ve always been troubled by this comparison of dollars of house price saved versus dollars of lives saved –not because I doubt either the calculations or assigning dollars to a life, which is standard in many cost benefit analyses. But my opinion, shared I think by many who deal with community reactions to aircraft noise, is that house prices really don’t reflect the adverse noise effects of living near a busy airport. For one thing, realtors and sellers go out of their way to down-play the aircraft noise issue.

Well, whether or not we want to pursue that debate, here come the Europeans and WHO, with “disability-adjusted life-years” (DALYs) as a method for quantifying any environmental health effect, and a report specifically addressing noise. Though my hopes for enlightenment about aircraft noise were immediately dashed when I learned that this report deals almost exclusively with the effects of road traffic noise, the DALY method may eventually have some use for comparison of aviation noise and emissions effects.

So how do we compute DALYs? Basically it’s the sum of years of life lost (e.g., premature mortality) and years lived with disability, or years of healthy life lost (e.g., suffering chronic bronchitis). The noise produced disabilities the WHO report examines are cardiovascular disease, cognitive impairment in children, sleep disturbance, tinnitus and annoyance. These are all adverse health effects consistent with the WHO definition of health as being “a state of complete physical, mental and social well-being.”

Computation of DALYs requires knowledge of the number of people exposed to each level of noise, a dose-response relationship that gives percent of people affected at each level, the “disability weight,” DW, assigned to the effect (DW equals zero means no health effect, DW equals one, you die), and the number of years of living with the disability or years of life lost. Obviously, many assumptions are required, but I like the way the large number of assembled subject area experts synthesized their knowledge and the research literature results to quantify each variable and calculate the DALYs for each health effect. 

What most struck me, was the number of experts (41 are listed) who participated in developing the report. In contrast, current U.S. efforts have required that many people come up to speed on the effects of aircraft noise on people, working with an additional very few who had actually worked in the field of aircraft noise effects. (Three cheers to the FAA for bringing in experts from outside the U.S. to assist with development of the Aviation Noise Impacts Roadmap.) To be clear, those who had to learn, were already experts, many in acoustics, just not in aviation noise and its effects.

In some ways, how sad. In the 1970’s the U.S. lead the world in developing the knowledge needed to formulate a national policy on noise and noise control. But those efforts all stopped short in the early 1980’s. Hence, most of those with expertise have retired and no new blood added for these three decades.

Now that we are concerned about how we can expand the U.S. air transport system, change airspace use, add runways, and increase the use of under-utilized airports, recognition has come that we better understand what the noise and air quality effects will be on society. Let’s hope that we can develop enough understanding to provide the aviation decision-makers with the information they need for science based noise and emissions policy. Perhaps a bit more of looking to research results gathered outside the U.S. would benefit our efforts.

TRB releases Critical Issues in Aviation and the Environment e-circular

Tuesday, April 5th, 2011

by Mary Ellen Eagan

TRB Transportation Research E-Circular E-C148: Critical Issues in Aviation and the Environment explores the environmental media affected by aviation activities and processes that link aviation and the environment. The circular consists of nine individually authored sections representing the authors’ expert opinions on these issues.

Critical Issues in Aviation and the Environment 2011

Many thanks to the authors of those sections:

E-C148 updates and expands upon previous circulars while maintaining their cross-disciplinary approach to reviewing subjects of interest to the civil aviation community in the United States. The circular focus is on the state of science, rather than on policy, and on identifying priority research with the potential to yield benefits during the next several years to several decades.

I hope you will find it a useful reference.

NEPA and NextGen: Airports can bridge the gap between industry and the public

Tuesday, March 15th, 2011

by Mary Ellen Eagan

Discussion of NextGen and NEPA issues was a hot topic at the U.C. Davis Noise and Air Quality Symposium earlier this month – not only in “formal” sessions and presentations, but informally over dinners, cocktails, and networking sessions.  Jason Schwartz of the Port of Portland presented a great graphic which summarizes the central role of airports in this discussion:

Courtesy of Jason Schwartz, Port of Portland

Of critical importance – and a potential significant benefit from the perspective of FAA officials tasked with rolling out performance-based navigation (PBN) procedures as quickly as possible – will be the role airports can play in outreach.  I believe this will be the key to maximizing understanding and minimizing controversy (and thus avoiding costly and lengthy environmental processes).

As shown in Jason’s slide, airports are uniquely positioned to understand the technical issues and urgency of industry to implement the procedures as well as the concerns of the community and elected officials to preserve their quality of life.   Airports can bridge this gap by engaging both sides in a constructive discussion and evaluation of environmental impacts (and benefits!) resulting from implementation of PBN.  We have been involved in such discussions at Denver International Airport, which FAA hopes to use as a model for collaborative engagement for its integrated National Airspace and Procedures Plan (otherwise known as the “Metroplex Project”).

The FAA is taking a major step to loosen key bottlenecks in metroplexes, the busy metropolitan areas where multiple airports and competing airspace lead to less-than-efficient operations.  The FAA intends to design integrated airspace and new procedures to de-conflict arrivals and departures in an initiative that will reach 21 such areas by 2016.

Source: FAA 2010

The goal of the Metroplex Project is to implement more efficient operations in metroplex areas. Study teams with representatives of the FAA and the aviation community will provide an expeditious but comprehensive front-end strategic look at each metroplex.  They will analyze operational challenges, assess current and planned airspace and procedures efforts, and explore new opportunities for solutions that are tailored individually to each metroplex. Once a study team has come up with the right changes for its metroplex, a design and implementation team will develop the changes and put them in place.  The first two metroplex areas – North Texas and Washington D.C. – have been identified as prototypes for early analysis.  The FAA has completed the initial concept studies for each and soon will be entering the design phase similar to the recent effort at Denver.  The next five metroplexes identified for study are: Atlanta, Houston, Charlotte, N.C., Northern California, and Southern California.

For a great summary on NextGen Implementation, read this report from FAA.

HMMH will be assisting the FAA to prepare NEPA documents for the upcoming metroplex studies.  I look forward to working with airports – the local experts – to identify important community and local government representatives and strategies for outreach.

As Chad Leqve of Minneapolis St. Paul International Airport pointed out on several occasions during the symposium, the rollout of PBN procedures presents a rare opportunity to achieve meaningful noise reduction over noise-sensitive communities.  We should not squander that opportunity.