Earth's environment can change drastically and challenge pilots as the fly across the globe. Pilots must be focused and ready to take-on any situation the comes their way. Sometimes there are situations that occur that can catch the pilot off guard. For example, wind shear can cause fatal damage to a pilot, their crew, and passengers if the pilot is not prepared. Wind shear can occur in the upper and lower levels of the atmosphere, but I will only be discussing the lower level atmospheric wind shear.

According to the Federal Aviation Administration (FAA) (2011), wind shear is defined as, "a rapid change in wind speed and direction over a short distance." In the lower portion of the atmosphere, wind shear can be caused by thunderstorms, temperature change, and obstruction. During thunderstorms, warm air rises on the outside of the storm and converge at the top of the storm. The warm air will then go to the center of the storm and rush to the surface at high speeds. Wind speeds can reach speeds of 100 knots per hour and can change direction up to 180 degrees. (FAA, 2011)

Temperature inversion wind shears usually occur in the southwestern region of the United States. (FAA, 2011)  During the night, the air is cooled at the surface up to a few hundred feet lower than the mountain range peaks. This cooling of air creates a temperature separation between the surface and the lower-level atmosphere. Once the warm air jet stream flows across the top of the calmer, cooler air, it creates wind shears that can change speed by 20-30 knots per hour and direction up to 90 degrees. (FAA, 2011)

Surface obstruction can also cause mini wind shears. The main obstruction that I am referring to are mountain ranges or larger buildings close to the runways. When a strong winds goes up and over mountain ranges or winding through buildings on the airports, there can be localized wind shears. Wind shears are to be expected by pilots when there are strong surface winds, the severity of the wind shear is completely unpredictable. (FAA, 2011)

Resources

FAA. (2011, August). Wind Shear. Retrieved from FAA Safety: https://www.faasafety.gov/files/gslac/library/documents/2011/Aug/56407/FAA%20P-8740-40%20WindShear%5Bhi-res%5D%20branded.pdf

Module 8: Air Traffic Control Entities

During this post, I will be discussing two Air Traffic Control entities that must be able to diligently work with one another in order to have successful operations. The first entity that I will be discussing is the Airport Traffic Control Tower's (ATCT) duties and responsibilities. Next I will discuss the duties and responsibilities of the Terminal Radar Approach Control (TRACON).

ATCT can be made up of anywhere between three and ten positions within it depending on how busy the airport is. Two of the positions that I would like to talk about are the ground controller and local controller. Ground controllers are ultimately responsible for ensuring the separation of  aircraft while being taxied from landing, aircraft being taxied prior to taking off, and managing ground vehicles in airport moving areas. (Nolan, n.d.)  The local controller is responsible for determining active runways, separation of aircraft in the local area and active runways, and issuing landing and takeoff clearances. (Nolan, n.d.)  These two positions have a significant impact on airport operations. If these positions, along with other positions are not careful, fatal accidents could occur.

TRACON, typically found at larger airports, hosts up to 40 approach and departure controllers. (Nolan, n.d.)  These controllers are surrounded by up to 20 monitors that displays incoming and out going aircrafts. While at larger airports, the approach and departure controllers are assigned airspaces to maintain since the job may be too big for one individual. (Nolan, n.d.)  TRACONs will ensure that departing aircraft air correctly deconflicted and then hand the responsibility of the aircraft to another TRACON to ensure continuous tracking is done on the airframe.

Module 7: The Airport and the Environment

Airports have many concerns when operating in their respective environments. For example, wildlife, pollution, terrain, and population are all concerns for airports when making operational decisions. During this post, I will be discussing noise issues and concerns for the airports neighboring populations. I will also discuss methods that are currently used and methods that are suggested for the future to reduce and/or eliminate the noise of airplanes.

There are a combination of noises that are made from different parts of an airframe. These parts include propellers, engines, flaps, landing gears, and operations that occur around the airport. Studies have been conducted by many doctors that show aircraft related noise has been proven to cause learning disabilities and hypertension. (Kaltenbach, Maschke, & Klinke, 2008)  In 2001, it was found that more than 2,900 adults had hypertension related symptoms when around continuous aircraft related noises between 55 and 72 decibels (dB).  (Kaltenbach, Maschke, & Klinke, 2008)  Furthermore, more than 2,000 men between the ages 40 and 60 were evaluated for a 10 year period. These evaluations concluded that there was a 20% increase to the risk of hypertension with continuous noises of 50 dB's.  (Kaltenbach, Maschke, & Klinke, 2008). Additionally, studies were conducted on over 2,800 children from ages 9 to 13 in 89 different schools. it was determined that an increase to aircraft related noises deteriorated silent reading comprehension and memory performance.  (Kaltenbach, Maschke, & Klinke, 2008)

While completely eliminating airport noises is impossible at the moment, the Federal Aviation Administration (FAA) currently has rules in place to reduce the noise levels of specific aircraft types. Currently there are four stages of noise levels created by the FAA. Stage 1 (Loudest), Stage 2, Stage 3, and Stage 4 (Quietest). The noise levels are identified in Code of Federal Regulation Title 14, Chapter 1, Subchapter C, Part 36. Prior to January 1, 2016, civil jet aircrafts that meet a weight less than 75,000lbs is required to meet the noise requirements of Stage 3 or stage 4; Aircrafts 75,000 or more will have to meet Stage 2, Stage 3, or Stage 4 requirements. (FAA, 2019) As of January 1st, 2016, regardless of the civil jet aircrafts weight, it must meet Stage 3 or Stage 4 noise level requirements. (FAA, 2019)  Furthermore, Helicopters are allowed to operate at Stage 1 and Stage 2 noise level requirements.

References

FAA. (2019, Janurary 9). Aircraft Noise Issues. Retrieved from Federal Aviation Administration (FAA): https://www.faa.gov/about/office_org/headquarters_offices/apl/noise_emissions/airport_aircraft_noise_issues/

Kaltenbach, M., Maschke, C., & Klinke, R. (2008, August). Health Consequences of Aircraft Noise. Retrieved from National Center for Biotechnology Information: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2696954/



Module 6: Legislative Acts

Laws and regulations are what helps ensure successful operations and safety in aviation. Laws and regulations are what the Federal Aviation Administration (FAA) use to hold people and airlines accountable. Rather than focusing on rules that hold pilots or air crews accountable for their actions, I would like to look into an aircraft structure regulation that promotes structure durability. More specifically, I will be discussing the Code of Federal Regulations (CFR) 14 §25.365 “Pressurized Compartment Loads”. This regulation defines the safety precautions to be implemented in the instance that a pressurized compartment is penetrated during mid-flight operations. 

FAA CFR 14 §25.365 is a regulation comprised of 6 sections that takes into consideration the safety of the passengers on board the aircraft. Section (g) of the CFR 14 §25.365 (2019) states, "Bulkheads, floors, and partitions in pressurized compartments for occupants must be designed to withstand the conditions specified in paragraph (e) of this section."  The FAA wants to ensure that if the frame of the aircraft is to be penetrated, then chairs and luggage compartments will not be pulled through the hole of the aircraft during the rapid depressurization process. This helps to increase the safety of all the passengers on board the air frame. 

An example of this situation occurring is on the Daallo Airlines Flight 159 on February 2nd, 2016. at that time, it was suspected that members of the Al-Shabaab terrorist group were the cause of the explosion. (Kriel, 2016)  These people brought an explosive devices disguised as a laptop on to the plane that exploded and penetrated the frame of the aircraft. The cabin immediately depressurized and unfortunately pull one passenger through the hole of the aircraft. However, due to the cabins durability, the aircraft remained in contact through the entirety of the event and landed safely.

Resources

Federal Aviation Administration. (2019, May 30). Title 14: Aeronautics and Space, Part 25: Airworthiness Standards: Transport Category Airplanes. Retrieved from Electronic Code of Federal Regulations: https://gov.ecfr.io/cgi-bin/text-idx?SID=77d90aa989f16f6c71fd99e5015dacba&mc=true&node=se14.1.25_1365&rgn=div8

Kriel, R. (2016, February 12). Source: 'Sophisticated' laptop bomb on Somali plane got through X-ray machine. Retrieved from CNN: https://www.cnn.com/2016/02/11/africa/somalia-plane-bomb/index.html