Certification Standards and
Technology Goals
Aircraft are required to meet the environmental certification
standards adopted by the Council of ICAO. These are contained
in Annex 16 (Environmental Protection) to the Convention
on International Civil Aviation. This Annex at present
consists of two volumes, viz., Volume I: Aircraft Noise
and Volume II: Aircraft Engine Emissions. These certification
Standards have been designed and are kept up to date in
order to respond to concerns regarding environmental impact
of aviation on communities in the vicinity of airports as
well as society at large.
More recently, ICAO, under the CAEP process, has undertaken
an effort to establish medium and long-term environmental
goals relating to three types of technologies, viz., noise,
NOx, and fuel burn. In addition, assessments of environmental
improvements expected from operational initiatives in the
medium and long term are also underway. This process is
being led by panels of independent experts to ensure transparency
and involvement from all stakeholders. The purpose of this
goal setting exercise is to provide stretch yet reasonable
targets for industry R&D to aim at in cooperation with
States.
Aircraft and Engine Emissions
Aircraft are required to meet the engine certification
standards adopted by the Council of ICAO. These are contained
in Annex 16 – Environmental Protection, Volume
II – Aircraft Engine Emissions to the Convention
on International Civil Aviation. These were originally
designed to respond to concerns regarding air quality in
the vicinity of airports. As a consequence, they establish
limits for emissions of oxides of nitrogen (NOx), carbon
monoxide, unburned hydrocarbons, for a reference landing
and take-off (LTO) cycle below 915 metres of altitude (3000
ft). There are also provisions regarding smoke and vented
fuel.
While these standards are based on an aircraft's LTO cycle,
they also help to limit emissions at altitude. Of particular
relevance is the Standard for NOx, a precursor for ozone,
which at altitude is a greenhouse gas. The standard for
NOx was first adopted in 1981, then made more stringent
in 1993, 1999, and 2005. Most recently, the eight meeting
of CAEP (CAEP/8) in February 2010 agreed on a new NOx Standard,
which improves on the current Standard by up to 15 per cent
with an effective date of 31 December 2013, as well as a
production cut-off of engines according to the current Standard
with an effective date of 31 December 2012.The ICAO
Engine Exhaust Emissions Data Bank (Doc 9646), issued
in 1995, contains a comprehensive database of aircraft jet
engine emissions certification data. Subsequent updates
of the data bank are available through the ICAO website.
In line with the recommendation by the GIACC (link to
menu “GIACC”) and the HLM-ENV/09 (link to menu
“HLM-ENV/09”), the eighth meeting of CAEP in
February 2010 agreed on a plan for the development of an
aviation CO2 emissions Standard, aimed
at having a Standard for consideration at CAEP/9 in 2013.
Key necessary steps toward a CO2 Standard
have been identified and this systematic approach is expected
to culminate in the adoption of a CO2
Standard in 2013. A methodology is under development to
account for complete life cycle analyses of any alternative
fuels.
Regarding particulate matter (PM) emissions, CAEP/8 agreed
to focus on non-volatile PM since the science is more advanced
in this area, compared to volatile PM. Establishment of
a certification requirement is targeted by 2013 and a certification
Standard by 2016.
The independent expert review for NOx reduction technologies
was completed in 2006 and subsequently updated for CAEP/8
in February 2010. The panel of independent experts decided
to maintain the following goals established in 2006:
Medium Term Goal (2016):
CAEP/6 levels – 45%, ±2.5% (of CAEP/6) at
an overall pressure ratio of 30
Long Term Goal (2026):
CAEP/6 levels – 60%, ±5% (of CAEP/6) at an
overall pressure ratio of 30
Similarly, a workshop to consolidate the knowledge base
for fuel burn improvements through weight reduction, aerodynamic
improvement, engine fuel efficiency improvement, and aircraft
system optimization was conducted in 2009 and a follow-on
review was conducted in May 2010. A report of these reviews
and workshop and the resultant medium and long term goals
for fuel burn reduction technologies will be presented to
the CAEP/9 meeting in 2013.
Aircraft Noise
Much of ICAO's effort to address aircraft noise over the
past 40 years has been aimed at reducing noise at source.
Aeroplanes and helicopters built today are required to meet
the noise certification standards adopted by the Council
of ICAO. These are contained in Annex 16 — Environmental
Protection, Volume I — Aircraft Noise
to the Convention on International Civil Aviation,
while practical guidance to certificating authorities on
implementation of the technical procedures of Annex 16 is
contained in the Environmental Technical Manual on the
use of Procedures in the Noise Certification of Aircraft
(Doc 9501).
The first generation of jet-powered aeroplanes was not
covered by Annex 16 and these are consequently referred
to as non-noise certificated (NNC) aeroplanes (e.g. Boeing
707 and Douglas DC-8). The initial standards for jet-powered
aircraft designed before 1977 were included in Chapter 2
of Annex 16. The Boeing 727 and the Douglas DC-9 are examples
of aircraft covered by Chapter 2. Subsequently, newer aircraft
were required to meet the stricter standards contained in
Chapter 3 of the Annex. The Boeing 737-300/400, Boeing 767
and Airbus A319 are examples of "Chapter 3" aircraft
types. In June 2001, on the basis of recommendations made
by the fifth meeting of the Committee on Aviation Environmental
Protection (CAEP/5), the Council adopted a new Chapter 4
noise standard, more stringent than that contained in Chapter
3. Starting 1 January 2006, the new standard became applicable
to newly certificated aeroplanes and to Chapter 3 aeroplanes
for which re-certification to Chapter 4 is requested. Most
recently, CAEP/8 in February 2010 requested the noise technical
group to review and analyze certification noise levels for
subsonic jet and heavy propeller driven-driven aeroplanes
and, based on the analysis, develop a range of increased
stringency options. This analysis will be considered at
the CAEP/9 meeting in 2013.
A Noise database NoisedB was developed in 2006 by the
French DGCA under the aegis of the International Civil Aviation
Organization (ICAO). The database is intended to be a general
source of information to the public on certification noise
levels for each aircraft type as provided by certification
authorities.Based on the success of the independent expert
process to set medium and long term NOx reduction goals,
a similar process was launched for noise reduction technologies.
This independent expert review was completed in 2008 and
the panel presented its final report to CAEP/8 meeting in
February 2010. The goals for four classes or categories
of aircraft were as follows:
| Aircraft Category |
Margin
to Chapter 4 (EPNdB) |
| |
Mid-Term
(2018) |
Long-Term
(2028) |
| Regional Jet |
13.0±4.6 |
20.0±5.5 |
| Small-Med. Range Twin |
21.0±4.6 |
23.5±5.5 |
Long-Range Twin |
20.5±4.6 |
23.0±5.5 |
| Long-Range Quad |
20.0±4 |
23.5±5.5 |
When compared to a baseline of today’s aircraft,
the goals show more promise of noise reduction for larger
aircraft because of a broader scope of technologies that
can be applied to such aircraft.
Read more (presentation Goals and Standards - The ICAO
Perspective)
