1. NPA 53b JAR OPS 1.235 Noise Abatement Procedures
Capt. Claude Godel
OST 06-1

2. JAR-OPS 1.235
Present text ( 1998) JAR-OPS Noise abatement procedures
(a) An operator shall establish operating procedures for noise abatement during instrument flight operations in compliance with ICAO PANS-OPS Volume 1 (Doc 8168-OPS/611).
Take-off climb procedures for noise abatement specified by an operator for any one aeroplane type should be the same for all aerodromes.
OPSG has been tasked to update this text
in order to meet noise targets that are increasingly demanded at all aerodromes
but in a manner consistent with safety.
The proposal intends to :
comply with ICAO PANS OPS
take advantage of any new technology implemented by the aircraft manufacturers
But keep it safe and simple for the pilots
Following a request of last OST, the JAR OPS text has been reworded and a new ACJ added to clarify some concepts.

3. New proposed JAR-OPS 1.235 JAR-OPS 1.235 Noise Abatement Procedures
When required to meet aerodrome noise abatement objectives an operator shall establish operating procedures for noise abatement which:
a) comply with ICAO PANS OPS Volume 1 (Doc 8168-OPS/611),
b) are designed to be simple and safe to operate with no significant increase in crew workload, particularly during the initial climb phase.
c) for each aeroplane type,
(i) comprise no more than two climb profiles, one of which shall meet the close-in noise abatement objective and the other the distant noise abatement objective, and
(ii) specify only one sequence of actions per climb profile.
d) ensure that safety has priority over noise abatement considerations.

4. New proposed ACJ to JAR OPS 1.235
Noise Abatement Procedures
“Climb profile” in JAR OPS (c) means the vertical path of the NADP as it results from the pilot’s actions (Engine power reduction, acceleration, slats/flaps retraction).
“sequence of actions” means the order and the timing in which these pilot’s actions are done.
Example: for a given aeroplane type when establishing the Distant NADP, an operator should choose either to reduce power first AND then accelerate or to accelerate first and then wait until slats/flaps are retracted before reducing power. The two methods constitute two different sequences of actions within the meaning of this ACJ.

5. New proposed ACJ to JAR OPS 1.235
The NADP procedures for an aeroplane type, should be defined by:
two altitudes which can be runway specific:
the altitude of the first pilot’s action (generally power reduction with or without acceleration). This altitude should not be less than 800ft AAL.
the altitude of the end of the noise abatement procedure. This altitude should not be more than 3000ft AAL.
one sequence of actions (close-in or distant)
On a case by case process a special agreement could be accepted by the authority of the operator for a specific runway (climb profile/trajectory), provided the safety of the operations remains the greatest priority. That agreement should then be aeroplane type/operator specific and the training aspects taken into consideration.

6. A closer look to the two ICAO procedures
Part V Chapter c)
c) To minimize the impact on training while maintaining some flexibility to address variations in the location of noise-sensitive areas, sufficient commonality shall exist between the departure procedures specified by the operator. There will be no more than two departure procedures to be used by one operator for an aeroplane type, one of which should be identified as the normal departure procedure and the other as the noise abatement departure procedure.
 d) Normal departure procedures typically include general noise reduction measures that encompass one of the two examples shown in the appendix to this chapter – Noise Abatement Departure Climb Guidance….
What can we understand?
- There shall be no more than two departure procedures
The, so called, “normal procedure” is in fact one of the two examples (NADP 2 a) on most of the aircraft.
Therefore we are not in contradiction with ICAO when choosing to write “two climb profiles” each of one being a noise abatement procedure.
And it sounds more environmentally correct…

7. A closer look to the two ICAO examples
Noise abatement climb example of a procedure alleviating noise close to the aerodrome (NADP 1)
2.4 On reaching an altitude at or above 240 m (800 ft) above aerodrome elevation, adjust and maintain engine power/thrust in accordance with the noise abatement power/thrust schedule provided in the aircraft operating manual. Maintain a climb speed of V 2 plus 20 to 40 km/h (10 to 20 kt) with flaps and slats in the take-off configuration.
3. Noise abatement climb -Example of a procedure alleviating noise distant from the aerodrome (NADP 2)
3.4 On reaching an altitude equivalent to at least 240 m (800 ft) above aerodrome elevation, decrease aircraft body angle/angle of pitch whilst maintaining a positive rate of climb, accelerate towards V ZF and either:
a) reduce power with the initiation of the first flap/slat retraction; or
b) reduce power after flap/slat retraction.
NADP 1 - Close in
Easy! : somewhere between 800ft and 2999ft (it’s written on the chart), reduce power but maintain speed and flaps/slats until 3000ft where acceleration takes place.
NADP 2 - Distant
We want it easy too!:
For a given type of aeroplane, the operator will have to choose between ICAO 3.4 a) and 3.4 b) and then fly the same procedure on each aerodrome where the Distant NADP is the better solution. NADP Distant 2 a) on one airport and NADP Distant 2 b) on an other is not permitted for the same aeroplane type because it is not the same sequence of action.

8. ICAO PANS OPS reminder Close in NADP 1 Distant NADP 2 3000ft 1500ft
Flap Retract
1500ft
3000ft
800ft
Best climb
Flap Retract
Close in
NADP 1
V2 + 10

9. CLOSE IN
Accel + retract
3000 ft
Accel + retract
3000 ft
V2 + 10
2000 ft
Power Red
V2 + 10
800 ft
Power Red
Type A aircraft on Aerodrome N°1
Type A aircraft on Aerodrome N°2
New proposition permits Power reduction height to be optimized for each given runway but sequence of action must remain the same.
The pilot has to remember three items : “I will fly a Close in, reduce power at xxxft and finish the NADP at xxxx ft”
The pilot’s workload remains acceptable. He will be able to concentrate on lateral track, frequency change, minimum safety altitude, weather radar,…

10. DISTANT
In the OPSG proposition, the two examples above will not be permitted for a same type of aircraft
Same sequence of action means either always power reduction and acceleration or always acceleration then power reduction. The operator has to choose.
The Pilot, again, should not have more than three items to remember:
The Distant sequence of actions for his type of aircraft
xxxx ft, the height of first action
Xxxxft, the end of the NADP
3000 ft
3000 ft
Power Reduction
Accel + retract
Accel + retract
Power Reduction
800 ft
800 ft
Type A aircraft on Aerodrome N°1
Type A aircraft on Aerodrome N°2

11. DISTANT (2)
3000 ft
3000 ft
Accel + retract
Accel + retract
1500 ft
Power Red
800 ft
Power Red
Type A aircraft on Aerodrome N°1
Type A aircraft on Aerodrome N°2
These two examples above will be permitted for a same type of aircraft
When the same sequence of action is used, the acceleration height may be optimized for each individual runway.
The Pilot has three items to remember:
The Distant sequence for his type of aircraft
xxxx ft, the height of acceleration for the departure runway
Xxxx ft, the altitude where the NADP ends

12. DISTANT (3)
3000 ft
3000 ft
Power Red
Accel + retract
Power Red
Accel + retract
1500 ft
800 ft
Type B aircraft on Aerodrome N°1
Type B aircraft on Aerodrome N°2
Again these two examples will be permitted for another type of aircraft (B)
It’s a different sequence of action but type B aircraft always uses that one.
The Pilot has three items to remember:
The Distant sequence for his type of aircraft
xxxx ft, the height of acceleration for the departure runway
Xxxx ft, the altitude where the NADP ends

13. Manufacturer State of the Art
FMS TAKE OFF Page:
Acceleration
+ Flap retraction
BOEING
AIRBUS
Thrust Reduction

14. Manufacturer Projects (Airbus)
Example of future development:
“Airbus are developing a new FMS function that should be available next year and will have a function called NADP (Standard on A380) which will allow the use of multiple noise abatement procedures optimised for individual runways for a particular set of operating conditions.
The power reduction altitude could be optimised as a function of the weight. It may be possible to uplink the noise abatement procedure to the FMS from the ACARS. There would be a planning tool, called ADAS Airbus Departure Analysis Software, to calculate best procedure. The FMS would have a noise page entered from the performance pages. The reduction altitude is the main parameter to optimise when designing Noise Abatement Procedure. If up-linked by ACARS, no additional workload for pilots. “

15. Manufacturer Projects (Boeing)
Example of future development:
“Boeing Noise Engineering expects to develop a planning tool to support the selection of noise abatement procedures by airlines. This tool will essentially combine with the Boeing Climbout Program (BCOP) to optimise departure procedures for noise abatement in compliance with safety requirements. The tool will consider MTOW, ambient conditions, thrust rating, flap settings, altitudes for thrust reduction and flap retraction, and the amount of thrust reduction, among others. Tool results could be uplinked to flight crews to provide guidance through FMS. Boeing expects to flight test the results of preliminary optimisation algorithms at a major European airport in 2006, and an initial version of the tool could be ready in time to support 787 deliveries. Any modifications required to the FMS to support multiple noise abatement procedures may be explored during the development of the tool.”

16. OPSG conclusion
The initial climb phase of flight is defined as critical and any changes must be assessed for their safety/workload impact.
We must limit the complexity and number of procedures during that phase.
Concerning the noise abatement procedure, the pilot’s before take off briefing should be limited to those three items:
“We will fly a Close in (or a Distant) sequence” (two different but clearly defined sequences of actions for a given aircraft type)
“The Power reduction (and/or the acceleration) will take place at xxxx ft”. (first pilot action depending on the type of sequence)
The NADP ends at xxxx ft
Noise abatement must always come second to safety considerations.
Noise abatement procedures shall be limited to the initial climb phase between 800 and, generally, 3000 ft above airport level.