On July 03, 2019

What you need to know about Reduced landing flaps

Pilots are among the main actors to improve fuel efficiency since they are the one in commands when executing the flight.

 

That’s why this new series of articles focus on tips and tricks for fuel-saving best practices such as Continuous Descent Approach (CDA) or Engine-Out Taxi In.

 

In this article, we will focus on a best practice that takes place during the landing phase: Reduced landing flaps.

 
What is Reduced landing flaps?

 

When conditions and safety allow it, the principle of Reduce Landing Flaps is to perform the final approach until the touchdown with flaps that are not fully deployed (reduced flaps).

 

Here are some examples of landing flaps configuration:

 

In blue, the reduced configuration and in red the full one:

 

Aircraft type ICAO code

Flaps configuration

FLAPS (°)

SLATS (°)

 

A320

Conf 3

20

22

Conf Full

35

27

 

B738

Conf 30

35

 

Conf 40

46

 

 

 

What are the benefits of Reduced landing flaps?

 

Selecting a reduced landing configuration has the following positive effects:

  • It reduces the drag and requires less thrust and less fuel consumption during the approach phase
  • It reduces the noise disturbance near airports
  • It provides a better approach angle with a lower pitch and steadier trajectory in turbulences

 

Is Reduced landing flaps configuration fuel efficient?

 

The approach is not the most fuel consuming phase of the flight, so you may think that there is not much to save during that phase. However, here are a few figures that demonstrate otherwise:

 

By applying a lower landing configuration, a single-aisle aircraft such as the A320 or B737 will save between 7 to 10 kg of fuel per flight. For larger aircraft, the benefit can exceed 25kg per flight.

 

reduced-landing-flaps-graph1-1

reduced-landing-flaps-graph2-1

 

As an example, let’s take an airline operating a fleet of only 20 single-aisle aircraft flying 6 flights a day: since a Reduced Landing configuration allows to save around 7 kg per flight, this will result in more than 300 tons of fuel saved per year (or more than 100,000 gallons), which represent a significant cost.

 

 

Can pilots make a difference?

 

Reduced landing flaps is a very common fuel-saving best practice. By calculating the landing performance, the pilots will ensure that the landing is possible with the Reduced Landing flaps configuration. It is the case at most international airports.

 

However, certain conditions may prevent applying it:

  • High altitude airports
  • Short runways
  • Low headwind that reduces lift
  • High temperatures and low atmospheric pressures
  • Need to vacate the runway quickly at the next taxiway

 

If you want to increase Reduced landing flaps application rate without compromising safety, here are some tips:

  • First, provide guidance on how to perform it and clear procedures that explain when to apply it or not
  • Focus on low altitude airports and where the runway is long enough
  • Communicate regularly with pilots to engage them and remind the procedure and its safety considerations.
  • Finally, in our opinion, the most efficient way to increase Reduced landing flaps application is to empower pilots with a tool (such as a mobile app) which enables them to have personal and confidential feedback on each of their flights and best practices, including 3D visualization.

 

 

References


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By Damien & Vincent

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