9.2 Weather Hazards

Incredible Pilot Skills Severe Windshear

"Tower, Snake 91, wind shear, 25 knots, one-mile final." 

"Snake 91, copy. Gain or Loss?"

"Loss." 

The first time I heard a pilot report wind shear, I had to dig into my brain to remember what the FAA Joint Order 7110.65 said about wind shear. I went off memory when I asked the pilot if it was a gain or a loss. I knew to broadcast it to the other flights arriving and departing, and that we would broadcast it on the ATIS. But what was that brief back and forth really about? 

Imagine a pilot on final approach to land. They are at 300 feet, descending to the runway. Suddenly, a downdraft pushes the aircraft's nose rapidly towards the runway. The pilot doesn't have enough altitude to recover and regain the altitude they've lost. They now find themselves much lower than they can recover from, and short of runway, to boot. 

Wind shear is a dangerous weather occurrence that pilots can experience in the air. It is a sudden change in wind speed and/or direction, an anomaly from the overall reported wind. Wind shear happens suddenly, with no visible warnings. What makes wind shear hazardous is its proximity to the ground. Without warning, wind shear can cause an aircraft's altitude to change (FAA, 2016). 

Wind shear can be caused by four reasons: weather fronts, thunderstorms, temperature inversions, and surface obstructions (FAA, 2008). The reason wind shear is reported in a gain/loss is that other pilots know if the reporting pilot gained or lost airspeed. Currently, pilots combat wind shear by reporting it when they experience it to to ATC. ATC can then relay the report to other aircraft. 

Word Count: 282

References

Aviation Channel 2010. [Username]. (2014, October 23). Incredible Pilot Skills Severe Windshear || Dangerous Landing during a Storm [Video]. YouTube. https://www.youtube.com/watch?v=MfGVkaDVu34

Department of Transportation. (2008). Wind Shear. Federal Aviation Administration. https://www.faasafety.gov/files/gslac/library/documents/2011/Aug/56407/FAA%20P-8740-40%20WindShear%5Bhi-res%5D%20branded.pdf

Federal Aviation Administration (FAA). (2016). Pilot’s Handbook of Aeronautical Knowledge. https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/phak/

Air Traffic Control Entities

 

Tower: Ground control and Local control 

Ground control and Tower control each have specific duties to ensure separation and an expeditious flow of air traffic. Per the FAA Joint Order 7110.65, Ground control's position is responsible for control of movement areas by taxiing aircraft or other vehicles. Movement areas include taxiways and ramps not under Local control (FAA, 2020). Like Local control, Ground control has its own phraseology for allowing or prohibiting aircraft and vehicles to maneuver on the movement area(s). 

Local control is air traffic, ensuring positive separation in the entire airspace - including runways. With both arrivals and departures, Local control ensures proper sequencing and spacing for aircraft. On departure, Local controllers provide departure information including runway in use, wind direction and speed, and altimeter setting if the pilot did not previously affirm the correct ATIS code. Upon arrival Local control's responsibility is to clear an aircraft for landing - by providing a safe and expeditious flow of air traffic, once again providing the runway in use, wind, and landing clearance (FAA, 2020). An example of a Local controller's landing clearance could be, "Mace 11, runway 32, wind two-eight-zero at four, cleared to land." This provides the pilot assurance that the runway is cleared for his or her arrival, and additional information to assist in landing. 

Ground control and Local control work closely together and communication between the two is critical. According to the FAA 7110.65, chapter 2, section 10, paragraph 3, both Local control and Ground control share many of the same responsibilities, including ensuring separation, initiating control instructions, monitoring communications equipment, ensuring proper strip marking is completed, and scanning the tower cab environment for anomalies, maintaining situational awareness. The Tower Team Concept Intent states there is no absolute division of responsibilities in the tower cab - everyone is equally responsible for ensuring safety at that facility (FAA, 2020).  

Word count: 306

Reference

Department of Transportation. (2020, December 31). FAA Order JO 7110.65Y - Air Traffic Control. https://www.faa.gov/air_traffic/publications/atpubs/atc_html/