Where is a likely location of CAT?

[Ref AC 00-6B, AC 00-30C 6.5] Where is a likely location of CAT? Ans: upwind of the base of the trough on the polar side of a jet stream According to AC 00-30C 6.5: “There are several patterns of upper-level winds that are associated with CAT. One of these is a deep, upper trough. The word “trough” refers to winds that dip southward, then rise northward, forming a trough-like pattern. A “ridge” is the opposite, […]

What’s CAT (Clear Air Turbulence)?

[Ref AC 00-6B, AC 00-30C 6.5] What’s CAT (Clear Air Turbulence)? Clear Air Turbulence (CAT) is a higher altitude turbulence phenomenon occurring (from 20,000 to 50,000 feet) in cloud-free regions associated with wind shear. CAT can occur between the core of a jet stream and the surrounding air. It can often affect an aircraft without […]

What’s the different between “Wind shear alert” and “microburst alert” ? (US)

[Ref US AIM Section 3 Airport Operations 4-3-7] What’s the different between “Wind shear alert” and “microburst alert” ? (US) Ans: “Wind shear alert” is the information from basic LLWAS; “microburst alert” is provided when LLWAS integrated with TDWR. LLWAS (Low Level Wind Shear Alert System) only provides Wind shear alert – wind shear alert […]

What’s “Severe Wind Shear”?

[Ref AC 00-54] What’s “Severe Wind Shear“? By FAA AC definition, “Severe Windshear” refers to a rapid change in wind direction or velocity causing airspeed changes(>) greater than 15 knots OR vertical speed changes (>) greater than 500 feet per minute (fpm).  

What’s VOR?

What’s VOR? VOR: the full name is Very High Frequency  Omni-directional Range, which is a very common in modern civil aviation industry. VOR transmitted between 108 – 117.95 Mhz is used for Navigation purpose and VOR transmitted between 118 – 137 Mhz is used for radio communication. If VOR is used as NAV Aid, it […]

What’s GPWS (Ground proximity warning system)

[Ref ACE The Technical Pilot Interview 152/348] The GPWS (Ground proximity warning system) is mandatory required for public transport aircraft over 5700 kg. It is a important system provide two major functions: 1) alert and 2) warning system. After reaching certain precomputerized active range, a central computer will then activate aural and visual alerts to warn the […]

Learning from Alitalia 404 : The importantance of Crew Resource Management (CRM)

[Ref Wiki] (Last Update: 2020 Apr 28 1535Z) The air crash of Alitalia Flight 404 (AZ404/AZA404) happened on November 14, 1990. The international passenger flight scheduled to fly from Milan, Italy, to Zürich, Switzerland, operated by Alitalia, crashed into the woodlands as it approached Zurich Airport killing all 46 people on board.[1] A Swiss investigation concluded that […]