Accretion of Ice
Describe the best countermeasures that you as a pilot can use to mitigate these risks. Each response must encompass a minimum of three pages and clearly present the problem and explain the best-practice countermeasure, documenting your answer. This is not an opinion paper.
3. Scenario: They didn’t expect it. One minute the Embraer-120 Brasilia, flying on autopilot in instrument meteorological conditions was level at 4,000 feet in a left turn on radar vectors to intercept the localizer for an ILS on Runway 03R at Detroit Metro/Wayne County Airport; the next minute it was in a 140 degree left bank and a 50 degree nose-down attitude. The crew fought to regain control of the airplane, but there wasn’t enough altitude. Comair Flight 3272, carrying three crew and 26 passengers, struck the ground in a steep nose down attitude killing all aboard. What was the cause of the dreadful accident? Ice. According to the NTSB, the airplane lost control and stalled because of an accumulation of a thin, rough accretion of ice on its lifting surfaces (Report No. NTSB/AAR-98/4).
Aircraft involved: Embraer 120
Discuss this NTSB report and any similar incidents identifying the associated risks, latent errors, and hazards associated with icing. What mitigation would you recommend and identifying ‘best practices’ to prevent incident/accidents of this type, as well as noting what the FAA, NTSB and LUSOA has to say about this.
Accretion of Ice
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Introduction
In the case of the Embraer-120 Brasilia, which crashed and claimed the lives of all the 26 passengers and the three crew members, ice accretion was the most likely cause of the accident. As the National Transportation Safety Board (NTSB) indicated in the initial report on the same incident, ice build up on the wings and other leading surfaces of the plane alters the ability of the plane to generate lifting force. Airflow over the wings and tail are altered leading to aerodynamic stall, which makes it hard to momentarily control the plane (Skybrary.aero, 2014). This is a condition that has been quite common and claimed quite a number of lives as the planes tend to dive straight into the ground, after the crew is deprived control.
Ice Accretion on Planes Surfaces
Ice accretion is one of the most common causes of plane crashes other than aspects related to structural and mechanical causes. Other than that the case discussed above, there have been other accidents where the accumulation ice on the front surfaces of the plane has led to a fatal end. Early 2009, in Buffalo, New York, a continental express plane dubbed flight 3407, lost control and suddenly started to pitch and roll while it was just five miles from the runway. Shortly after, the plane crashed killing all the passengers and the crew aboard. Although the media jumped on to the story that the pilot may have desecrated the guidelines by the company, for having engaged the auto pilot on a plane that was propeller powered, it was discovered icing played a major role in the crash (Borrell, 2009).
Accretion ice is caused by the accumulation of ice on the top edges of the wings and other front surfaces of the plane. Given that the temperature of the surfaces such as the wings at leading edge are supposed to be at the ambient temperature of the air, wind dynamics, air and water droplets play a great role. When air that is loaded with the water droplets hits the leading edge of the wing, air tends to slide easily over and past with the help of the currents created. Water on the other hand tends to be much heavier that air and thus may not pass over and below the wing as easily (Steuernagle, Wright & Roy, 2014). This means that some of the water droplets will bluster on the leading surface. If the water in the air is super cooled, meaning that it is cooled below zero degrees, it is unstable and will freeze immediately it hits the leading edges. This process leads to accumulation of ice on the leading edges forming a double horn shape.
Risks, latent errors, and hazards associated with icing
When the ice forms on the leading edges of the plane, such as the wings, windshield and the propellers among others, it changes the plane’s flying dynamics. As the ice builds on the front surfaces, the air flow on the surfaces of the...