Aircraft noise and emissions concerns may become the most important strategic obstacles for future development of air transport. These concerns impact the system in many ways, including:
• changes in certification requirements for aircraft
• changing aircraft traffic management
• introduction of environmental levies or the market based approach of emissions trading
Particularly, noise pollution has been cited as a major issue for residents on flight paths, including a health risk. A 2013 study in the British Medical Journal revealed that those who lived near Heathrow were 10-20% more likely to be admitted to a hospital for heart disease or failure; a corresponding American study revealed that for every 10-decibel increase in noise, the risk went up by 3.5%. Residents have therefore demanded stronger regulations on noise pollution and more lenient flight paths, to the point of taking legal action.
Solutions for reducing noise and emissions include the idea of a “Global Night Curfew”, where flights could only operate under certain times of day, and a “high-speed rail” that could substitute for flights under 500 miles. However, many of these ideas are expensive and unfeasible to implement. Therefore, airlines have instead opted to reduce emissions and noise pollution through design, including via electric propulsion systems.
- Runway use policies creating potential for runway incursion/excursion and/or wrong runway takeoffs/landing
- New take-off and landing profiles which may reduce safety margins
- Noise curfews result in pressures to compress departures and arrivals into time slots near the beginning and end of curfew hours.
- For instance, Continuous Descent Approach (CDA) is a low-noise approach procedure. Aviation safety experts raise important concerns with flying aircraft at reduced power at lower altitudes. The recovery rate for any kind of disturbance at lower altitudes is reduced significantly. At lower altitudes on less power, aircraft is more difficult to control due to air density. Bird strikes and engine stalls are much more likely at lower altitudes at reduced power and any last minute alterations could create result in loss of control.