Aircraft

Airplane computer system could save fuel and reduce noise on landings

Airplane computer system could...
A pilot consults the LNAS display before beginning a landing approach
A pilot consults the LNAS display before beginning a landing approach
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A pilot consults the LNAS display before beginning a landing approach
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A pilot consults the LNAS display before beginning a landing approach

Airliners can make a lot of noise and use a lot of fuel when they're coming in for a landing. A new onboard computer system, however, was recently shown to be effective at addressing both problems.

Known as the Low Noise Augmentation System (LNAS), the technology was developed by scientists at the German Aerospace Center (DLR).

Based on data such as weather conditions and aircraft type, it starts by providing pilots with a recommendation on the altitude at which to begin their landing approach. It also advises them on factors like the optimum airspeed, sink rate, and timing of deployment of the airbrakes and landing gear. Those recommendations may change as the landing is in progress, reflecting changes in one or more external variables.

A team from Switzerland's Empa research institute recently tested the system at the Zurich Airport, working with DLR personnel and their Airbus A320 ATRA (Advanced Technology Research Aircraft).

For the exercise, 23 pilots from Swiss Airlines, Edelweiss Air and Lufthansa were divided into two groups. Flying the ATRA with a DLR co-pilot, 14 of the pilots performed a total of 43 LNAS-assisted landing approaches, while the other nine pilots performed 27 approaches without the system. That said, the latter group was still advised to try making their approaches as quiet and fuel-efficient as possible.

Based on readings from ground-based stations, it was found that use of LNAS reduced flight noise by up to 3 decibels – this represents about a one-third reduction of the perceived volume.

Additionally, when the system was utilized, the ATRA burned an average of 8.9 kg (19.6 lb) less kerosene on its approaches. Although this may not sound like much per flight, it is estimated that if LNAS had been used on all Swiss Air flights in 2017, it could have saved about 500 tonnes (551 US tons) of fuel.

The follow-up DYNCAT (Dynamic Configuration Adjustment in the TMA) project, beginning next month, will be aimed at integrating the LNAS technology into the central navigation computers of existing commercial airliners.

Source: Empa

2 comments
paul314
Less noise and an annual savings of about $300K. Obviously this new technique must be stopped.
Jinpa
"Based on readings from ground-based stations, it was found that use of LNAS reduced flight noise by up to 3 decibels – this represents about a one-third reduction of the perceived volume." Perceived volume generated by what, where, and perceived by whom, where? 3dB isn't a difference most humans could detect between any two volumes at or above normal ambient noise at an airport or even in a house or office. Use a sound meter app on your cellphone to test it for yourself. It is a meaningless claim. An A320 landing would generate way more than 80 dB as measured at the runway, but no one stands there to listen or measure. Inside the airport, you would be too far from the runway to hear it at all. A house under the flight path would be assaulted by the aircraft passing overhead, but the story didn't say who is the supposed beneficiary or where situated. Poor editing because no context was demanded of the writer.