Stage 5 Aircraft Noise Standards Approved in US – What does it mean for airports?

October 25th, 2017

By Jessica L. Cohen

On October 4, 2017, the Federal Register published a new noise standard for newly certified large airplanes.[1]  The noise standard, Stage 5, applies to large jets with a Maximum Takeoff Weight (MTOW) greater than or equal to 55,000 kg manufactured after December 31, 2017. Jets with a MTOW of less than 55,000 kg will need to adopt this standard by December 31, 2020. This is in correlation with the ICAO Chapter 14 noise standard, adopted July 14, 2014, for the purpose of ensuring efficiency for aircraft manufacturers in certifying their aircraft. In short, Chapter 14 and Stage 5 include the same requirements in their standard to reduce any extraneous cost or effort by requiring aircraft manufacturers to comply with two separate standards.[2]


Figure 1: EASA Certified Aircraft Noise Levels vs Chapter 3 Limit Source: HMMH modified EASA jet aeroplanes noise database (Issue 24 of 10/12/2015), January 22, 2016; updated March 2017


The new Stage 5 standard requires a cumulative reduction of 7 EPNdB (Effective Perceived Noise Level, in decibels) from Stage 4 standards, which correlate to ICAO’s Chapter 4 standards. Chapter 4 or Stage 4 standards, adopted in 2006, required a cumulative reduction of 10 EPNdB from the Chapter 3 limit. Therefore, Stage 5 compliant aircraft require a cumulative reduction of 17 EPNdB from the Chapter 3 limit. Figure 1 shows the different aircraft Stages versus the Chapter 3 (Stage 3) limit as well as some of the different aircraft types that fall into each Stage’s noise standard currently. Table 1 (below)  provides contextual information regarding the labels shown in Figure 1 (above).


Table 1: Aircraft categories as defined by ICAO/CAEP independent experts (IE)


For Stage 4 and Stage 5 requirements, the calculation of noise margins involves utilizing microphone locations at three places, which correspond to Chapter 3 noise limits. The cumulative result of subtracting the measured noise levels at three microphone locations from the limits determines whether an aircraft meets Stage 5 requirements.


Table 2: Analysis of Number of Jet Aircraft with a MTOW greater than 55,000 kg, Manufacturers, and Stage 5 Compliance Source: EASA, June 2017,


As Figure 1 shows, many aircraft currently in operation already meet Stage 5 requirements. Table 2 shows aircraft with a MTOW of greater than or equal to 55,000 kg, where future iterations of the aircraft types produced by these manufacturers will need to meet the Stage 5 noise standard beginning on December 31, 2017. Currently, approximately one third of these aircraft meet the Stage 5 noise standard and their manufacturers are Airbus and Boeing.


Figure 2: Summary of Stage 5 Noise Standard Compliance by Manufacturer and Number of Aircraft Types Source: EASA, June 2017,


Figure 2 (above) shows the number of aircraft types by each manufacturer that meet the Stage 5 noise standard currently, displaying whether all, the majority, a partial amount, a minimal amount, or none of that registered aircraft of meet the standard. Figure 3 below breaks this information down by aircraft type.


Figure 3: Stage 5 Noise Standard Compliance by Aircraft Type and Manufacture for Jet Aircraft with a MTOW of greater than or equal to 55,000 kg Source: EASA, June 2017,

[1] The Stage 5 Noise Standard was originally proposed by the FAA on January 14, 2016.


Aviation Environmental Design Tool (AEDT) 2017 Update

September 29th, 2017

by Robert Mentzer

FAA has released its latest version of the Aviation Environmental Design Tool (AEDT 2d).  Released on September 27, 2017, the model is a free upgrade for existing AEDT 2b/2c licensed users and is available from the FAA AEDT website.  All FAA actions requiring noise, fuel burn or emissions modeling and for which the environmental analysis process has begun on or after September 27, 2017 are required to use AEDT 2d.

The major features of this release are:

  • for the first time since AEDT was released the FAA has added new aircraft data to the model that were not in the legacy models (Boeing 737 MAX, Bombardier Global 5000 and 6000 and BADA support for the A350-900).
  • AEDT 2d will only operate on the SQL 2012 platform (prior releases used SQL 2008)
  • MOVES improvements including: inputs including roadway, parking facilities and construction zones and inventory file improvements
  • VALE report improvements
  • Dynamic Grid support for Time-based noise metrics
  • Creating and editing vector tracks
  • Track dispersion editing
  • Metric results import and combine feature improvements

This release also includes several model enhancements and bug fixes and includes a known list of issues.

HMMH provided INM training for more than 20 years. HMMH now offers AEDT 2d training with the same focus on practical implementation from a user perspective.  This course provides users with an overview of the new model, with a focus on transitioning from legacy tools and computational resources.

Click here for more information or to register for HMMH’s next AEDT 2d course held in Burlington, MA on November 14th, 2017.

The AEDT support website is the technical support and information hub for AEDT. Support requests, feedback on bugs, and feature requests should be submitted through this website. The AEDT installer and support resources such as documentation and frequently asked questions (FAQ) are also available on the AEDT Support website.

Remaining Optimistic Despite President Trump’s Paris Agreement Decision

June 2nd, 2017

by Katherine B. Preston

As I sit here digesting the news that the Trump Administration has decided to withdraw from the Paris Agreement, which in my opinion is a decision that will have negative consequences for the country beyond just environmental impacts, it strikes me that what the U.S. does at a federal level isn’t a deal-breaker on climate.  Despite this unfortunate turn of events, I have reason to be optimistic.

How can this be?  Well, first of all, the feds weren’t really doing all that much to begin with on climate change.  While the Obama Administration accomplished some important initiatives designed to address climate change, such as corporate average fuel economy standards, the clean power plan, energy efficiency standards for federal buildings – I believe the real action is happening in the private sector and at the state and local level.  Motivated states and cities have been doing what the federal government hasn’t been able to do like set greenhouse gas emissions reduction targets, renewable energy generation goals, and putting resiliency plans into place.  Just ask California, Massachusetts, New York City, Seattle, Chicago, and so many more – too numerous to list here.

According to data from the 2010 census, over 80% of Americans live in urban areas – which means that our collective contribution to climate change and exposure to climate risks is overwhelmingly focused on American cities.  This is GOOD news, because it is cities across the country that are taking some of the most aggressive actions on climate change.   In fact, there are almost 600 U.S. members of the organization ICLEI – Local Governments for Sustainability taking action on climate change and becoming more resilient communities.  The United States Conference of Mayors strongly denounced the President’s decision and pledged to continue to work towards the goals in the Paris Agreement.  Climate deniers at the federal level can’t stop all that progress at the local and state level.

Sure the corporate average fuel economy standards and the Clean Power Plan rule were important.  But there are seismic shifts happening in sectors of our economy and economic forces in play regardless of what is happening (or not happening) in Washington, D.C.  Renewable energy development is on the rise as costs continue to decrease, and states continue to enforce renewable portfolio standards.  Solar power generation has risen at an exponential rate in the past 10 years, and as costs continue to decrease, this trend will continue.   Hybrid and electric vehicles continue to become more cost competitive and EV ranges are increasing.   Disruptive technologies hold enormous potential to address our collective GHG emissions too.  Autonomous vehicles could potentially realize a significant decrease in fuel consumption because of efficiency gains (humans aren’t really great drivers after all).

And let’s not forget the recent trend of activist boards forcing companies to fully account for the risks posed by climate change (see Exxon, for example).  This is a particularly exciting development, and I look forward to watching as investors and consumers vote more with their wallets to encourage continued progress.

Many industries are taking it upon themselves to act, whether it’s to better manage risk (regulatory, public relations, financial or otherwise), or because they view it as the “right thing to do”.  My own industry is a good example.  Airports across the world are voluntarily participating in carbon emissions reductions programs.  Some are required by local laws, others because of community expectations, some to compete with peer airports, and others because their leadership understands that managing the airports’ contribution to climate change carries more benefits than costs.  The Airport Carbon Accreditation program (just one of several frameworks in use for managing CO2 emissions) has grown to 189 participating airports and resulted in 206,000 tons of CO2 reductions last year alone.  A drop in the bucket compared to global GHG emissions, but it’s a start and it’s growing.

All of this isn’t to imply that there aren’t actions that the White House and Congress could take to push our economy even further in the right direction on renewable energy and energy efficiency.  Of course there are – and it’s too bad that we’re not.  We could reinstate the investment tax credit which helped the solar industry grow exponentially over the past 10 plus years by helping to bring costs down.  We could implement a cap and trade system – or even better a carbon tax and invest the profits in R&D to develop better renewable energy and energy efficiency technologies we could sell to the rest of the world.  We could ensure parity between renewables, biofuels and fossil fuels by giving equal subsidies and tax breaks to producers of these fuels instead of favoring oil and gas.  We could make sure farmers have access to crop insurance for biofuel crops to lower the barrier to entry.  We could implement renewable energy portfolio requirements. These are obviously just a few examples of many different actions that we could take at the federal level that would make a difference.  But as we’ve seen, progress in the private sector, at the state and local levels and internationally will not stop, regardless of the decisions made in Washington.

That is perhaps one final reason for optimism about the decision of this Administration.  There is a gaping opening for other countries to take more of a leadership role.  China and the EU have jointly stepped up to the plate, and India has indicated it will stay in.   Hopefully our hiatus on the global stage is a short one, but in the meantime others will continue to their efforts.  American cities, states, businesses, organizations and individuals will join the rest of the world in addressing climate change.  Though I am disappointed in the decision to withdraw the U.S. from the Paris Agreement, there are many reasons to remain hopeful that our collective fight against the greatest challenge of our generation will continue.

Plastic Pollution and Healthy Oceans

April 25th, 2017

by Katherine B. Preston

This Earth Day I had the pleasure of volunteering at a community event designed to raise awareness about living more sustainably and reducing our collective environmental footprint.   I serve on the Board of Directors for a local organization, Sustainable Tallahassee, whose mission is to promote environmental stewardship and economic vitality in our community through education and collaboration.  At Sustainable Tallahassee, we have many initiatives, but the one we chose to highlight at Saturday’s Earth Day event was plastic pollution – specifically from single use water bottles.  We found that a lot of the festival goers with single use bottles justified using them because they recycle the bottles (which is great!) but that doesn’t quite negate the impacts.

Did you know that Americans drink around 50 billion (yes, Billion!) bottles of water each year – and that only around 20-25% of those bottles are recycled (according to National Geographic). That means around 38 billion plastic bottles are sent to a landfill each year in the U.S. alone, and many end up in our waterways and oceans.  The environmental impacts don’t stop there, unfortunately.  It takes about 17 million barrels of oil each year to manufacture all these bottles (again – U.S. estimates only), and approximately 3 liters of water to produce 16 ounces of bottled water.  Let’s not forget about the energy needed to transport all these bottles to retailers and homes, and to refrigerate them, and the impact from groundwater pumping.

If the environmental impacts alone don’t convince you to permanently ditch the bottled water, consider that all of this damage doesn’t come cheap either. On average, bottled water costs thousands of times more than tap water, and is no safer than what comes out of your faucet (unless you live in areas with lead pipe problems of course).  I am guilty of grabbing bottle waters at times, and tell myself that since its only once in a while it’s ok (plus I am very forgetful when it comes to reusable mugs and water bottles and have lost so many over the years).  After this year’s Earth Day event, I have made a pledge to do much, much better – and bought myself a new stainless steel water bottle since the last one was left on a plane somewhere in Baltimore…

If you spent time in this costume in the Florida heat educating your fellow citizens of the evils of bottled water, you’d make a vow to never use a plastic bottle again too! HMMH would be happy to send you one of our new HMMH stainless steel water bottles, just for reading this – please email us to order yours!

BTS Releases National Transportation Noise Map

March 23rd, 2017

by Mary Ellen Eagan


The U.S. Department of Transportation’s Bureau of Transportation Statistics’ (BTS) initial National Transportation Noise Map was released earlier this week.  It shows that more than 97 percent of the U.S. population has the potential to be exposed to noise from aviation and Interstate highways at levels above below 50 decibels (roughly comparable to the noise level of a humming refrigerator).  A much smaller segment of the U.S. resident population has the potential to be exposed to higher levels of aviation and Interstate highway noise. Less than one-tenth of a percent of the population could potentially experience noise levels of 80 decibels or more, equivalent to the noise level of a garbage disposal.

The purpose of the noise map is to facilitate the tracking of trends in transportation-related noise, by mode, and collectively for multiple transportation modes. The data allow viewing the national picture of potential exposure to aviation and highway noise. The data also allow viewing of the potential exposure at the state or county level.

The National Transportation Noise Map will be an addition to the National Transportation Atlas Database (NTAD), a set of nationwide geographic databases of transportation facilities, networks, and associated infrastructure available from the BTS Geospatial Data Catalog. The layers will be updated on an annual basis, and future versions of the National Transportation Noise Map are envisioned to include additional transportation noise sources, such as rail and maritime.

The BTS map contains aircraft and road noise inventory data provided as web map services (WMS) for use with Geographic Information Systems (GIS), computer programs that can store, analyze, and present spatial or geographic data.

The mapping was developed by the DOT’s Volpe Center, using data sources from the Federal Aviation Administration (FAA) and Federal Highway Administration (FHWA) to create a comprehensive map of noise levels. The FAA’s Aviation Environmental Design Tool was used to model the average number of daily flight operations from airports across the country, excluding airports with exclusively military operations. To determine daily road noise data, algorithms from the FHWA’s Traffic Noise Model were used in conjunction with data from the Highway Performance Monitoring System to obtain the average daily noise levels for automobiles, medium trucks, and heavy trucks. The acoustics modeling used in developing these noise layers uses conservative, simplified methods, and only considers transportation noise (no other ambient noise sources). Documentation on the modeling assumptions is available at The noise data in the layers should be used for the purpose of tracking trends, not for assessing impacts. This data release represents the first year of data that can be used to analyze future trends.