Long Island North Shore Helicopter Route Environmental Study 

This report presents the results of the noise and emissions analysis of helicopter operations along the North 

Shore Helicopter Route of Long Island, New York performed by the Federal Aviation Administration, with the 

assistance of the Volpe Center’s Environmental Measurement and Modeling group. 

Noise 

The FAA’s Office of Environment and Energy tasked the Volpe Center to conduct an analysis of the noise of 

helicopters operating under Visual Flight Rules (VFR) along the north shore of Long Island. This analysis 

examines current helicopter noise along the route. The route is shown below in Figure 1. 

Figure 1. North Shore Helicopter Route 

 

Helicopter Operational Source Data 

The ATAC Corporation provided Performance Data Analysis and Reporting System (PDARS) information to 

the Volpe Center. This PDARS data set included helicopter operations near and over Long Island around 

Memorial Day, 2011 (May 27 to May 31) and the 4th of July, 2011 (June 30 to July 5). When providing the 

data, ATAC provided a breakdown of helicopter operations, which is shown in Table 1. Using this peak season 

holiday data, the analysis assumed an average daily number of 42.8 helicopter operations (40.1 operations 

during the day and 2.7 operations during nighttime hours). 

Table 1. Helicopter operations from PDARS data 

Time 5/27 5/28 5/29 5/30 5/31 6/30 7/1 7/2 7/3 7/4 7/5 Total

Day 82 38 24 66 29 42 58 10 10 45 37 441

Night 2 2 1 3 1 3 4 3 2 6 3 30

 

The FAA’s Aviation Environmental Design Tool version 2A (AEDT 2A) was used to model the noise of these 

operations. U.S. Census Bureau 2010 population data were used to determine the population impacted by these 

operations. 
Processing 

The Volpe Center converted the PDARS data into a format usable by AEDT 2A. The PDARS data were used 

to generate track, fleet, and profile (altitude) data which were imported into AEDT 2A. Standard AEDT 

processes were used for fleet data. Flight specific altitude/speed profiles from the PDARS data were created for 

the helicopter performance profiles. These profiles were inserted directly into the AEDT fleet database for the 

respective helicopters being modeled. AEDT 2A was then run to calculate the noise of each of the flights and 

to generate the total noise impacts presented in this evaluation. Note that the numbers of operations were scaled 

from seasonal holiday time frames for an average annual day. Given that operation levels were drawn from 

around Memorial Day and Fourth of July – days when operations are known to be high in number – and the 

average annual day was created from these numbers, the average annual day reflects a higher level of operations 

than if a normal average annual day had been used. The assumed higher levels of operations result in higher 

noise levels than would result from a normal average annual day. 

The majority of helicopter operation information did not contain specific helicopter types. Given this gap in the 

data, each helicopter operation was assigned to one of three helicopter types that have been used over Long 

Island: light helicopters, represented by the Robinson R-44; medium helicopters, represented by the Eurocopter 

AS-350; and heavy helicopters, represented by the Sikorsky S-76. Actual altitudes flown were taken from the 

PDARS data. All operations were modeled as overflights: takeoff and landing flight segments were modeled as 

climbs and descents at the beginning and end of the track, respectively. 

To represent the cumulative helicopter noise environment, all helicopter operations in the vicinity of the route 

were modeled. This includes helicopters operating to and from MacArthur Airport (ISP) and helicopters which 

operate exclusively on either the east or west side of Long Island, even though they are not using the North 

Shore Route. In addition, helicopters that fly the route and fly near the route were also modeled. Figures 2 and 

3 illustrate the routes modeled in the analysis. 

Figure 2. Helicopter operations outside the affected area or flying to/from ISP 
Figure 3. Helicopter operations that are primarily following or paralleling the North Shore route 

Results and Analysis 

Table 2 below shows the results of the noise analysis. It presents the Day-Night Average Sound Level (DNL) 

noise levels and the population affected by the modeled helicopter noise. The analysis of the existing condition 

shows no population exposed to helicopter noise over a level of DNL 45 dB (decibels). To help put the North 

Shore noise levels in context, the average DNL level in quiet suburban residential areas is 50 dB.1 

Table 2. Population Exposure at Noise Levels 

Noise Level DNL 30-35 dB DNL 35-40 dB DNL 40-45 dB DNL 45-50 dB 

Population 2,992,284 2,329,766 728,665 0 

The rule is intended to maximize utilization of the existing North Shore Helicopter Route, which will secure and 

improve upon the existing low levels of helicopter noise that have to date been voluntarily achieved. In 

response to some commenters’ concerns that the rule might result in a significant noise impact on communities, 

there is not a reasonable potential for that to occur. To cause a significant noise impact, the rule would have to 

increase noise by DNL 1.5 dB or more at or above DNL 65 dB over residential areas.2

 Given that existing noise 

does not exceed DNL 45 dB, it would require thousands of additional daily flights along the North Shore 

Helicopter Route to produce enough noise to result in a significant noise impact, and this is not a possible 

outcome of the rule or reasonably foreseeable under any circumstances. 

 

1 Federal Agency Review of Selected Airport Noise Analysis Issues, Federal Interagency Committee on Noise, August 1992. 2

 FAA Order 1050.1E, Environmental Impacts: Policies and Procedures, Appendix A, Section 14, June 8, 2004. 
 

Emissions 

Context for Emissions Analyses

A commenter to the NPRM estimated that the average helicopter engine burns between 45 and 55 gallons per 

hour. (For twin engine helicopter, the fuel burn may be doubled). They also alleged that compliance with the 

rule will increase average flight time by 10 minutes, which they estimated will result in an annual increase of 

fuel burn of 116,875 gallons. 

According to the commenter, the total number of helicopter operations (to and from the East End airports) 

historically has been approximately 15,000 annually. Based on the commenter’s assumption that North Shore 

Route usage is 85% of the total (12,750 operations), then the added 10 minutes per flight would equate to 

127,500 minutes (2,125 hours). Therefore, at a rate of 55 gallons per hour, the commenter calculated that 

116,875 additional gallons of fuel will be consumed. 

No specific factual basis for the alleged 10-minute increase in flight time was provided by the commenter. The 

rule does not mandate entry or exit points for helicopters using the route, nor does it require operators to fly any 

specific route to or from the North Shore Helicopter Route. Therefore, it is not possible to quantify any 

increase in fuel consumption that might occur as a result of the rule. Based on the FAA’s analysis of PDARS 

data, fuel burn under current voluntary conditions along the North Shore Helicopter Route is roughly 453,000 

gallons per year. The commenter’s estimated increase of 117,000 gallons per year would amount to a 25 

percent increase in fuel burn. The FAA does not regard this as a reasonable potential result of the rule, 

considering the reported high level of compliance with the voluntary route, the commenter’s apparent 

assumption that even those flights currently in compliance with the route would fly 10 minutes longer as a result 

of the rule, and the absence of mandates in the rule that would substantially increase fuel burn. 

For the purposes of this emissions evaluation, the commenter’s data is helpful insofar as it provides an upper 

bound for fuel consumption that can be used to show that the rule could not result in noncompliance with 

applicable emissions requirements. Therefore, this emissions analysis provides calculations based on the 

commenter’s assumptions to demonstrate regulatory compliance with applicable emissions regulations. 

Emissions Analysis

First, calculations (Equation 1 through 4) were performed using a worst case fuel consumption based on the 

commenter’s assumptions, as follows: 

 Rotorcraft Type: S76, B430, AW139, and AS365 

 Annual increase in fuel burn: 117,000 gallons 

 Annual increase in flight time: 2,125 hours 

The commenter suggested the S76, B430, AW139, and AS365 as acceptable two engine helicopters to operate 

over water. From this list of rotorcraft, the AW139 and AS365 appear to be primarily used by the U.S. Coast 

Guard. The B430 was not specifically identified in EDMS (Emissions Dispersion Modeling System), but a 

comparable rotorcraft, the B407 with the same engine, was available for analysis. In addition, the S76 was 

found in EDMS as a viable commercial/private rotorcraft for use in this evaluation. The S76 and B407 

emissions information was extracted from EDMS. Due to limited rotorcraft operations data at Long Island 

landing sites, the emissions indices were selected from EDMS based on the highest rate of emissions regardless 

of flight segment for the Sikorsky S-76 Spirit (See Table 3). These selected indices provide a more 

conservative emissions estimate. 

Table 1 lists the conversion factors and emission factors/indices utilized in estimating an emissions inventory 

based on the commenter’s assumption of 117,000 gallons of fuel being consumed. The emission indices for 

Sulfur Dioxide (SO2), Total Hydrocarbons (THC), and Oxides of Nitrogen (NOX) are multiplied by the total 
fuel consumption to determine the total emissions. The Particulate Matter (PM10) emission factor is multiplied 

by the number of hours operating to determine total PM10 emissions. The number of additional hours of aircraft 

operation is estimated to be 2,125 hours. A conversion factor is applied to THC to obtain Volatile Organic 

Compounds (VOCs). Table 2 lists the worst case emissions inventory presented in U.S. Short tons based on 

this conservative emissions inventory methodology. 

Table 1. Conversion Factors and Emissions Rates 

Factor/Emission 

Rate Description 

Specific Weight of 

Fuel 6.8 lbs/gal of jet fuel 

Mass Conversion 2.2 lbs per kg 

U.S Short Ton 

Conversion 907.18 kg per U.S. Short Ton 

THC Emission Index 56.67 g/kg - Sikorsky S-76 Spirit; T700-GE-700 Idle Emission Rate 

THC to VOC 

Conversion 

1.15 VOC to THC - FAA/EPA RECOMMENDED BEST PRACTICE FOR 

QUANTIFYING SPECIATED ORGANIC GAS EMISSIONS FROM AIRCRAFT 

EQUIPPED WITH TURBOFAN, TURBOJET, AND TURBOPROP ENGINES 

Version 1.0 5/27/2009

NOX Emission Index 8.61 g/kg - Sikorsky S-76 Spirit; T700-GE-701 Take-off Emission Rate 

PM10 Emission Rate 0.3633 kg/hr – U.S. Environmental Protection Agency (EPA), EPA’s Procedure 

for Emission Inventory Preparation, Vol. IV, Mobile Sources. 1992

SO2 Emission Rate 

Based on a 98% conversion to SO2 with jet fuel having 0.068% sulfur content -

Coordinating Research Council, Inc., Handbook of Aviation Fuel Properties, Third 

Edition, CRC Report No. 635, Alpharetta, GA., 2004. 

Results and Analysis 

The North Shore helicopter route is located entirely within Suffolk County, New York. This area has been 

designated by the Environmental Protection Agency (EPA) under the Clean Air Act as a nonattainment area for 

particulate matter (PM-2.5) and a moderate nonattainment area for ozone.3 In addition, the state of New York is 

within the Ozone Transport Region established in section 184(a) of the Clean Air Act, 42 USC § 7511c(a). 

EPA has determined that for such nonattainment areas, emissions of less than 50 tons per year of volatile 

organic compounds and 100 tons per year of nitrogen oxides, PM-2.5, or sulfur dioxide are de minimis.

4

 

Using the methodology described above, the analysis indicates that emissions of these pollutants from 

combustion of an additional 117,000 gallons of fuel would be well below levels determined by the EPA to be de 

minimis. 

Table 2. Emissions Inventory Results Demonstrating Compliance below the 50 and 100 Tons per Year de 

minimis Thresholds (All values are in tons per year) 

VOC NOX PM10 SO2

25.98 3.43 0.85 .27 

Note: The PM10 estimate can be used as a surrogate for PM2.5 emissions. 

 

3

 See U.S. Environmental Protection Agency (EPA), “Currently Designated Nonattainment Areas for All Criteria Pollutants,” 

available at http://www.epa.gov/oaqps001/greenbk/ancl.html. 4

 40 CFR § 93.153(b)(1). 
 USDOT Research and Innovative Technology Administration March 14, 2012 

 Volpe Center Environmental Measurement and Modeling Division 

Long Island North Shore Helicopter route Page 6 of 7 NY N. Shore noise & emissions eval 3-21-12.docxEquation 1 

ܥܸܱ	݊݋ܶ	ݐݎ݋݄ܵ	ܷܵ ?

ൌ 	

ܥܪܶ	݃	56.67

݇݃	݂ݑ݈݁ ൈ ൭117,000	݈݃ܽ	݂ݑ݈݁ ൈ ൬6.8	݈ܾ 1	݈݃ܽ൰ ൈ ൬ 1	݇݃ 2.2	݈ܾ൰൱ ൈ ൭൬1	ܷܵ	݄ܵݐݎ݋	ܶ݋݊ 907.18	݇݃ ൰ ൈ ൬ 1	݇

1,00

ܥܸܱ	݊݋ܶ	25.98 ൌ

Equation 2 

? ܷܵ	݄ܵݐݎ݋	ܶ݋݊	ܱܰݔ ൌ 	 8.18	݃	ܱܰݔ ݇݃	݂ݑ݈݁ ൈ ൭117,000	݈݃ܽ	݂ݑ݈݁ ൈ ൬6.8	݈ܾ 1	݈݃ܽ൰ ൈ ൬ 1	݇݃ 2.2	݈ܾ൰൱ ൈ ൭൬1	ܷܵ	݄ܵݐݎ݋	ܶ݋݊ 907.18	݇݃ 

ݔܱܰ	݊݋ܶ	3.26 ൌ

Equation 3 

0.85 ൌ ݎ݄	2,125 ൈ ൰൱݃	1,000 ݇݃	1 ൬ ൈ ൰ ݇݃	907.18 ݊݋ܶ	ݐݎ݋݄ܵ	ܷܵ	1൭൬ ൈ ݎ݄ ܯܲ	݇݃	0.3633 	 ൌ଴ ଵܯܲ	݊݋ܶ	ݐݎ݋݄ܵ	ܷܵ ?

Equation 4 

? ܷܵ	݄ܵݐݎ݋	ܶ݋݊	ܱܵݔ ൌ 	ቌ൭117,000	݈݃ܽ	݂ݑ݈݁ ൈ ൬6.8	݈ܾ 1	݈݃ܽ൰ ൈ ൬ 1	݇݃ 2.2	݈ܾ൰ ൈ ൬1	ܷܵ	݄ܵݐݎ݋	ܶ݋݊ 907.18	݇݃ ൰൱ ൈ 0.068%ቍ ൈ 98
 USDOT Research and Innovative Technology Administration March 14, 2012 

 Volpe Center Environmental Measurement and Modeling Division 

Long Island North Shore Helicopter route Page 7 of 7 NY N. Shore noise & emissions eval 3-21-12.docx

Table 3. EDMS Emissions Indices for Specific Pollutants and Modes of Operation for T700-GE-700 and 

(All values are in g of pollutant per kg of fuel. The most conservative values are shaded to indicate the hi

this analysis.) 

Aircraft 

Type 

EDMS Equivalent 

Type 

EDMS 

Equivalent 

Engine 

THC 

Take Off 

THC 

 Climb 

Out 

THC 

Approach

THC 

Idle 

NOx 

Take Off 

NOx 

Climb 

Out 

S76 Sikorsky S76 Spirit T700-GE-700 0.39 0.49 0.37 56.67 8.61 8.18 

B430 Bell 407 250B17B 0.30 0.40 5.20 20.00 6.60 5.96 

AW139 No information in EDMS; Researched suggested Coast Guard Helicopter 

AS365 No information in EDMS; Researched suggested Coast Guard Helicopter