Weather-Related Aviation Accident - Essay Example

Running head: WEATHER-RELATED AVIATION ACCIDENT Name Lecturer Course Date Introduction Aviation industry is priding itself as being the safest mode of transport in the modern world. However, weather-related accidents, in both small and large aircrafts, has and will still remain as a major concern in the aviation safety at present, despite all the efforts put in the research and development since the invention by the Wright Brothers hundred years ago. According to statistics, weather is a major cause of aviation accidents and incidents. Approximately 23% of the accidents are reported to have been caused by the weather (Safety, 2007). The weather has a great impact on the national cost on delays, unexpected operation costs, injuries and damage costs which is estimated to be $ 3 billion (Middleton, 2003). Weather-related accidents have been reported all over the world. For example, on 5th December, 2003, a Cessna 172N Skyhawk ZK-EOA, crashed during a pilot training session near Lake Luna. This was reported to be as a result of strong wind shear and resultant severe turbulence in the mountainous region. The Regency Express Air Flight collided with trees in 1998 at Victoria due to wind and thick cloud layers. Weather has, therefore, been a significant part of the accidents, despite the advancing technologies in the forecasting and the displaying of weather hazards, for example, turbulence, lighting, icing, cloud cover, high winds, storms, thunderstorms and visibility (Middleton, 2003). Therefore, it is important that the meteorological department that operate in the airports to examine and analyze the weather conditions especially during flights to minimize the accidents. Regency Express Air Flight 434, Mount Taum, 23 November 1998 Regency Express Air flight 434, serial number 208B0061, was heading to Victoria International Airport from Vancouver International Airport, on a night visual flight rules (VFR) when it collided with foliage on Saltspring Island. The island is located approximately four nautical miles (nm) north of British Columbia, Victoria International Airport. On impact, the aircraft broke apart and resulted to a post-fire crush. The solely occupant of the aircraft, two pilots, sustained grave injuries, as the aircraft was totally destroyed. This fatal catastrophe occurred at 0030 Pacific Standard Time (PST). According to the communications and recorded data, the aircraft departed from runway of Vancouver 08R at 0012 PST and had a complete climb, a right hand turn towards Active Pass, a direct tract. Apart from the last part of the flight, it leveled off at 2000 feet above ground level (agl) (Transportation Board of Canada, 1998). As it approached Active Pass, the pilot made a call to any traffic in the Victoria area, alerting them on their intention to connect left-base for a landing at the Victoria airport on runway 09. After several minutes, they made a radio call informing the traffic that they were 10nm back, and prepared for a landing on runway 09. Communications data showed that, a final position report was given as aircraft approached Beaver Point which is south-east Point of Saltspring Island. From recorded radar data, the aircraft had made a turn to the right, and had started to track towards the high ground north of the Victoria International Airport. The aircraft gradually began a descending turn to the left, at 0026 towards the south east before colliding with the trees in the vicinity of Mount Taum. Information from the crash sites showed that the cargo aircraft was at the flight level when it immediately collided with the trees and its flight path was actually lined up with the east side of the airport. The captain of the aircraft was a qualified pilot who had a valid commercial licence together with valid instructor and instrument ratings. He was familiar with the route as he had routinely flown between Vancouver and Victoria. The co-pilot held also a valid licence. The company operations manual (COM) had authorized him to operate as a non-rated pilot. A non-rated pilot is an untrained pilot on a particular aircraft (Middleton, 2003). The purpose of a non-rated pilot is mainly to assist in command incase a first officer is unavailable or not required. Under the provisions, the non-rate pilot has no flights duties but assist in flight planning and loading activities. Aircraft information showed that the weights and centre of gravity was within the certified limits. The maximum take-off weight was 3969 kg. According to the Canadian Aviation Regulations (CARs), there exist weather conditions that are to be met by the VFR flight in airspace. These requirements are: all aircraft are supposed to operate with good visual reference to the surface, distance of the aircraft should be less than one mile horizontally and 500 feet vertically from the cloud, visibility of the flight should not be less than three miles. The hourly observations/forecasts of the area indicated that the crew could probably expect local stratus ceilings to be between 400and 1500 feet, in the onshore area while the visibility of ½ to 3 statute miles in mist and fogs. The hourly observation for Victoria was valid when the crew was planning for the flight. Though there was a slight indication of temporary condition of 4000 feet broken but it did not show any low cloud or visibility levels in the area of forecast. The weather observation at 2300 was very much consistent with the forecast and the wind was reported from 90 degrees True at 5 nm per hours, scattered cloud layer at 1600 feet above ground level (agl), visibility of 15 statute miles, a broken ceiling at 3500 feet above ground level. Strong low levels winds from the south were being caused by the deepening pressure gradient. Actually one of the pilots who flew on the same night confirmed the conditions (Transportation Board of Canada, 1998). When the accident aircraft was airborne, at 0016, a forecast which was amended was issued for Victoria. The forecast clearly indicated a temporary condition would be expected between 2330 and 0200, leading to a broken ceiling at approximately 2000 feet agl (Transportation Board of Canada, 1998). The clouds had thickened and worsened from the previous reports of a scattered cloud layer at 1600 feet. However, the information was issued immediately the crew had concluded their preflighting plans. The visual meteorological conditions at Victoria area indicated a broken layer of cloud at 1400 above sea level (asl) while the visibility below this cloud was at 12 statute miles. The main cause of this accident was showed to be as a result of obstacle caused by the low layer of cloud which. This made the crew to lack good visual in the flight path. Thus, they were not able to maintain the separation between the terrain and the aircraft by visual means. However, the accident could have somehow been prevented if the obstacles clearance requirements were available for the major commercial flights (Safety, 2007). Cessna 172N Skyhawk ZK-EOA Crash- 5th Dec, 2003 Atmospheric turbulence poses an ever persistent aviation risk to aviation stakeholders. It is as a result of air movements, winds, and has been linked to many accidents. It is important for crews to understand the nature of turbulence especially clear air turbulence. This type of turbulence is almost impossible to detect, and mostly catches the pilots unprepared. This is because it cannot be detected visually, from the cockpit since it only involves air currents. Worse still, it gas remained undetected by conventional weather radars. Due to high computational costs and probable suppression of flow separation by internal gravity wave downdrafts mechanical turbulence in hydrostatic-scale flows can be easily ignored. On 5th December, 2003 the mountain flying training flight aircraft Cessna 172N crashed at approximately 1630 hours (McCready, 2005), 2 km east of Lake Luna, Otago. The aircraft was reported not to have returned to Queenstown after a training flight with two persons on board- the trainee pilot and a well experienced instructor pilot. It was on a pilot training session run by the Wakapitu Aero Club. Having departed at 1532 hours, the flight plan detailed an estimated time of arrival to be 1652 hours. It was registered to have surpassed the ETA and contacted for response by the ATC at 1718 hours. This initiated a search by 1759 hours which was conducted up to around 1935hrs when the wreckage was found with one fatal, the instructor and a seriously injured pilot trainee. The final report by the Civil Aviation Authority of New Zealand indicated that the personnel in charge of the training was well trained, licensed and experienced having flown 1236 hours, including 80 hours gliding and 773hrs on Cessna 172 aircraft (McCready, 2005). This was in addition to 326 hours mountain flying. Prior to the accident, he had flown thrice on training schedules, one being the Lake Luna route. The aircraft was also in good mechanical condition with the flight weight and center of gravity being within normal limits. Meteorological records of the weather laid blame on weather conditions for being causative of the accident. This was in reference to wind and clear air turbulence (CAT). The records indicate that winds were increasing with time over Queenstown. This was by the meteorological office SIGMETs and an on-looker who reported strong gusting northwesterly wind, which was equal to a fresh gale having between 34 and 40 KT of wind speeds. There was a storm and gust which hindered walking. This also reduced visibility in the area. A wind shear, reported by the Queenstown ATIS also contributed to the overall condition. The wind was blowing at right or near right angles to the terrain where the aircraft was found. The severity, strength and wind extent increased due to downdraughts and turbulence found on the lee side of the mountain ranges. There were rotors which do cause severe downdraughts and turbulent which resulted in sink and a high vertical sink. This was evidenced by the nose-wheel assembly crash and leveled wings. The wreck trail was indicative that the Cessna 172N had a left turn before impact leading into an area of possible rotor activity (McCready, 2005). Rotor areas are areas of severe turbulence due to obstructed airflow. Downdraughts and turbulence will generally be found on the lee side of features and will increase in severity and extent with increase in wind strength (CAA). The turbulence experienced is also subject to factors such as wind speed, airflow directions across the terrain which comprise wind shear, and obstruction size and shape. This is an extraordinarily challenging subject long studied by engineers, computational fluid dynamics experts and atmospheric experts (Kaplan, Huffman, Lux, Charney, Riordan, & LIn, 2002). It occurs in a micro scale environment making it hard to predict. In the rotor activity area, interactions between gravity waves and flow-aligned jet stream undulations lead to occurrences of strong surface gusts. Strong shears on upper and bottom surfaces of the Cessna 172N combined forming a funnel-shaped shear zone in which the turbulence from the breaking gravity waves flowed down. This is in addition to downburst of turbulence resulting from the interactions of the jet-front and down-slope windstorm dynamics between the mountain ranges. Coupled with obstructions, this movement of air may lead to lens-shaped cloud in case the air has sufficient moisture. If the leeward side of the cloud is ragged, one can expect a severe turbulence downwind of the clouds (CAA). This downburst of turbulence has the visual appearance of a shaft of heavy precipitation both in shape and in the way it acts through the domain (Clark, et al., 2000). Turbulence leads to loss of control of an aircraft. This is by causing weather-induced damage (Briggs, Reverly, Evans, Sandifer, & Jones, 2010). NASA, in this study, considers this as loss of control event secondary to aircraft damage leading to an accident. Severe turbulence may also lead to a control upset, which NASA defines as being caused by pilot error and cannot be regulated via technology (Briggs, Reverly, Evans, Sandifer, & Jones, 2010). In the report evaluating the causative factors, there were seven accidents out of the 12 evaluated whose primary cause was amongst others the unplanned stall from insufficient airspeed in level-off, which affects the stability of the crew in addition to spatial disorientation. This is during take-off, en route and landing. The next most common causes of upset were icing, visual flight rules, and adverse wind conditions. Conclusion Weather conditions continue to play a continue to play a central role in aviation accidents and incidents globally. The weather-related accidents remain a significant cause concern in aviation safety intiating reports and recommendations by all stakeholders: governments, avaition safety authorities and aircraft owners and manufacturers. This is inspite of reports indicate human error as common. Weather is a primary contributing factor that has been recorder to out-do rapid technological advances in forecasting and displaying. This is during take-off, approach and as well full air borne cruise at any altitude. The above cited incidences are just examples indicating the fatalities relating to the accidents. Reference Briggs, J., Reverly, M., Evans, J., Sandifer, C., & Jones, S. (2010). Causal Factors and Adverse Conditions of Aviation Accidents and Incidents Related to Integrated Resilient Aircraft Control. Virginia: National Aeronautics and Space Administration . CAA. (n.d.). Good Aviation Practice. Retrieved October 17, 2011, from Civil Aviation Authority of New Zealand: www.caa.govt.nz Clark, T., Hall, W., Kerr, R., Middleton, D., Radke, L., Ralph, M., et al. (2000). Origins of Aircraft-Damaging Clear-Air Turbulence during the 9 December 1992 Colorado Downslope Windstorm: Numerical Simulations and Comparison with Observations. American Meterological Society Vol. 57 , 1105–1131. Kaplan, M., Huffman, A., Lux, K., Charney, J., Riordan, A., & LIn, Y. (2002). Characterizing the Severe Turbulence Environments Associated With Commercial Aviation Accidents. Virginia: NASA. Kuwait Airways Flight Safety & Quality Assurance Division . (2008). An In-house Newsletter of Operations Dept. Flight Safety Vol.3, No.$ , 1-4. McCready, T. (2005). Aircraft Accident Report Occurence Number 03/3531: Cessna 172N Skyhawk ZK-EOa. New Zealand: Civil Aviation Authority of New Zealand. Middleton, J. (2003). On the Trail of Wakes. Flight Safety Australia, available as http://www.casa.gov.au/ fsa/2003/sep/index.asp Safety. (2007). Air Transport New, 31 January Transportation Safety Board of Canada. (1998). Aviation Investigation Report A98P0303: Regency Express Air Operations . 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The aircraft gradually began a descending turn to the left, at 0026 towards the south east before colliding with the trees in the vicinity of Mount Taum. Information from the crash sites showed that the cargo aircraft was at the flight level when it immediately collided with the trees and its flight path was actually lined up with the east side of the airport. The captain of the aircraft was a qualified pilot who had a valid commercial licence together with valid instructor and instrument ratings.

He was familiar with the route as he had routinely flown between Vancouver and Victoria. The co-pilot held also a valid licence. The company operations manual (COM) had authorized him to operate as a non-rated pilot. A non-rated pilot is an untrained pilot on a particular aircraft (Middleton, 2003). The purpose of a non-rated pilot is mainly to assist in command incase a first officer is unavailable or not required. Under the provisions, the non-rate pilot has no flights duties but assist in flight planning and loading activities.

Aircraft information showed that the weights and centre of gravity was within the certified limits. The maximum take-off weight was 3969 kg. According to the Canadian Aviation Regulations (CARs), there exist weather conditions that are to be met by the VFR flight in airspace. These requirements are: all aircraft are supposed to operate with good visual reference to the surface, distance of the aircraft should be less than one mile horizontally and 500 feet vertically from the cloud, visibility of the flight should not be less than three miles.

The hourly observations/forecasts of the area indicated that the crew could probably expect local stratus ceilings to be between 400and 1500 feet, in the onshore area while the visibility of ½ to 3 statute miles in mist and fogs. The hourly observation for Victoria was valid when the crew was planning for the flight. Though there was a slight indication of temporary condition of 4000 feet broken but it did not show any low cloud or visibility levels in the area of forecast. The weather observation at 2300 was very much consistent with the forecast and the wind was reported from 90 degrees True at 5 nm per hours, scattered cloud layer at 1600 feet above ground level (agl), visibility of 15 statute miles, a broken ceiling at 3500 feet above ground level.

Strong low levels winds from the south were being caused by the deepening pressure gradient. Actually one of the pilots who flew on the same night confirmed the conditions (Transportation Board of Canada, 1998). When the accident aircraft was airborne, at 0016, a forecast which was amended was issued for Victoria. The forecast clearly indicated a temporary condition would be expected between 2330 and 0200, leading to a broken ceiling at approximately 2000 feet agl (Transportation Board of Canada, 1998).

The clouds had thickened and worsened from the previous reports of a scattered cloud layer at 1600 feet. However, the information was issued immediately the crew had concluded their preflighting plans. The visual meteorological conditions at Victoria area indicated a broken layer of cloud at 1400 above sea level (asl) while the visibility below this cloud was at 12 statute miles. The main cause of this accident was showed to be as a result of obstacle caused by the low layer of cloud which. This made the crew to lack good visual in the flight path.

Thus, they were not able to maintain the separation between the terrain and the aircraft by visual means. However, the accident could have somehow been prevented if the obstacles clearance requirements were available for the major commercial flights (Safety, 2007). Cessna 172N Skyhawk ZK-EOA Crash- 5th Dec, 2003 Atmospheric turbulence poses an ever persistent aviation risk to aviation stakeholders. It is as a result of air movements, winds, and has been linked to many accidents. It is important for crews to understand the nature of turbulence especially clear air turbulence.

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