Runway Overruns
In the last few years, runway overruns have contributed to a large percentage of fatalities involving runway accidents; according to the US National Transportation Safety Board (NSTB), out of 1332 runway accidents between 1995 - 2007, 379 of these accidents were due to runway overruns which led to 680 fatalities. [1]
Runway overruns are defined as situations when aircraft on takeoff or landing roll extends beyond the end of the runway.
Images
Aftermath of the runway overrun of Air France Flight 358 in Toronto
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| Picture embedded from Wikimedia on 16 Sep 09 | Picture embedded from National Geographic on 16 Sep 09 | |
Video
The video highlights some overrun accidents, its causes and offers solutions to the problem, some of which will be dealt with below
| (Video embedded from YouTube on 15 Sept 2009) |
For a more comprehensive synopsis of the incident of Air France 358, please refer to Air France 358
Causes of Runway Overruns [2]
Weather
- Heavy Showers/Thunderstorms make the runway wet and slippery, making it difficult for the pilot to control the aircraft during landing
- Winds also play a factor due to strong cross or tail winds making it difficult to control the aircraft
- Inaccurate weather information passed by ATC to the pilot due to slow updating of weather devices paint a wrong and misleading picture to pilots causing them to miscalculate their landing techniques
Pilot Error (Human Factors)
- Incorrect judgment in prevailing weather/runway conditions leading to the aircraft landing too long or too fast on the runway
- Incorrect Braking Techniques applied upon landing resulting in insufficient braking force applied rendering the aircraft unable to stop in time
- Incorrect flare technique upon landing
- Failure to arm spoilers prior to landing
- "Missionitis" Mindset making the pilot want to accomplish the mission of landing the aircraft even in adverse weather conditions/ high stress situation when diverting is more appropriate
Aircraft
- Brakes malfunction
- Anti skid system malfunction
- Hydroplaning
Organization
- Money making especially with the poor economy is of primary importance and the airline company would like all aircraft to land and take off on time and not to divert even in bad weather as it would result in delays and loss of money
Ways to minimize risk of Runway Overruns [3]
- Strict adherence to aircraft SOPs
- If due to prevailing weather conditions SOPs recommend a diversion, it should be followed
- Knowledge of meteorological conditions
- A good knowledge of the movement of weather, up to date and accurate reports of impending weather would enable the pilot to make informed decisions on whether it is viable and safe to proceed/continue with the flight
- Sound understanding of aircraft performance and systems
- This would enable pilots to know the capabilities and limitations of the aircraft in bad weather and to select the correct landing configuration in adverse situations
- Communications and teamwork
- Good two way communications and teamwork between the pilots are important as there can be occasions when a senior pilot might want to press on to land even though the junior pilot feels otherwise leading to poor teamwork and coordination prior to a probable difficult landing
- Organization/ Company mission
- The mission of an organization should encourage flights to be completed safely at all times instead of a flight HAS to be completed at all times because of profits; this will not put adverse pressure on the pilots to complete the flight at all costs even in bad situations
- Training
- Only with proper training comes the experience and expertise to mentally prepare the pilot for a safe landing in bad conditions
Recommendations and Prevention
Background
In the US, the NTSB recommended certain safety features to which all major commercial airports should meet FAA requirements of having a Runway Safety Area or EMAS by 2003.
Due to another runway overrun in 2005 and the slow progress of airports following these safety recommendations, Congress to prevent any further delay passed the Launtenberg Law requiring FAA to ensure that all major US commercial airports have either of these safety features by 2015 and to report to Congress annually on its progress. [4]
Runway Safety Area (RSA)
RSA is defined as "the surface surrounding the runway prepared or suitable for reducing the risk of damage to airplanes in the event of an undershoot, overshoot, or overrun from the runway."
- Established at end of each runway to a maximum 1000ft and 500ft wide
- Enhance safety what with additional 1000ft of prepared area without obstacles or obstructions
- Minimal damage to aircraft and injury to passengers [5]
Engineered Material Arrestor Systems (EMAS)
FAA recognized and acknowledged the problems of achieving a RSA at all airports due land limitations and undertook revolutionary research on the use of materials for arrestor systems to "arrest" the motion of aircraft in the event of an overrun.
EMAS works by using a light-weight, crushable concrete material, placed beyond the departure end of a runway, to stop or greatly slow an aircraft that overruns the runway exerting predictable deceleration forces on its landing gear as the EMAS material crushes. [6]
The video below provides an in depth look at EMAS in action
| (Video embedded from YouTube on 15 Sept 2009) |
To date, there have been four incidents (3 at JFK airport and 1 Greenville Downville Airport) where EMAS has successfully arrested commercial aircraft which has overrun the runway and in several cases has prevented injury to passengers and damage to the aircraft.
Want to know more?
- Runway Overrun Prevention
- This article provides ways for pilots to understand and mitigate risks associated with runway overruns during flight.
- About EMAS
- This website provides a comprehensive overview of how EMAS works.
