On December 21, 2018

What you need to know about Reduced Acceleration Altitude

Pilots are the main actors to improve fuel efficiency since a lot of initiative to save fuel must be applied during flights.

 

That’s why this new series of articles will focus on giving you tips and tricks for many industry best practices for fuel efficiency.

such as Continuous Descent Approach (CDA) or Engine-Out Taxi In.

 

In this article, we will focus on a best practice during the climb phase: Reduced Acceleration Altitude.

 

 

What is Reduced Acceleration Altitude?

 

Reduced Acceleration Altitude is a fuel efficiency best practice during the climb phase.

 

Its principle is to accelerate at an altitude lower than what is usually done. In most cases, the altitude is reduced from 3000ft to 800ft. For lighter aircraft, it can go down to 400ft.

 

By accelerating at a lower altitude, the clean configuration is reached earlier and drag is reduced. The following graph shows different climb profiles.

  • In red, the usual NADP1 procedure, where the aircraft accelerates at 3000ft
  • In green, the perfect application of Reduced Acceleration Altitude, where the aircraft accelerates at 800ft

 

RAAL-schema-web

 

 Figure 1: Reduce Acceleration Altitude best practice

 

 

Is Reduce Acceleration Altitude efficient? What are the benefits?

 

First, the efficiency of this best practice depends on noise abatement procedures. Indeed, it is only applicable when noise abatement procedures (specified on airport’s AIP) allows accelerating below 3000ft.

 

Wondering what are the typical fuel savings for applying this best practice?

 

The chart below shows what are the typical fuel saved, depending on the aircraft type:

 

raal-chart

 

Figure 2: Typical fuel saved and cooldown time, depending on the aircraft type

 

 

The benefits than can be expected are about 16 kg per flight for a TurboProp up to 200 kg for a Long Range aircraft, which is non-negligible!

 

 

Can pilots really make a difference?

 

Priority number one is always safety, especially in the climb phase which is very busy and requires to be particularly focused. Therefore, you might think that applying Reduced Acceleration Altitude won’t be a priority for many pilots.

 

But we observe that many airlines achieve a very high application rate (75%+) on this best practice without compromising safety.

 

If you don’t know where to start to increase Reduced Acceleration Altitude application rate without compromising safety, here are some tips:

  • First, provide guidance on how to perform Reduced Acceleration Altitude and clear procedures that explain when to apply it or not
  • Provide to pilots with a list of airports where NADP2 is allowed
  • Communicate regularly with pilots to engage them and remind the procedure and its safety considerations.
  • Finally, we strongly recommend empowering pilots with a dedicated tool (such as a mobile app) which enables them to have a personal and confidential feedback on each of their flights and best practices, including 3D visualization.

 

 

If we take the example of Ukraine International Airlines: before using SkyBreathe® MyFuelCoach, as can be seen in January 2017, they already had a very high rate of application: they exceeded 75% application.

 

After only 8 months using MyFuelCoach, they had a 95%+ application rate, which means that with the right information delivered in the hands of your pilots, almost absolute excellency can be reached!

 

 

uia-airline-raal

Figure 3: Reduced Acceleration Altitude in application from beginning of application

of SkyBreathe® MyFuelCoach™ application for pilots

 

 

If you want to learn more about how MyFuelCoach can help you, simply ask:

 

DISCOVER MYFUELCOACH

 


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Want to learn more about Ukraine International Airlines fuel efficiency story?

Discover the case study:

 

 UIA-case-study

Download Case Study

By OpenAirlines

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