These study guide questions were submitted by real pilots who actually interviewed with Cathay Dragon
What is the inter-tropical Convergence Zone? Near the equator, from about 5° north and 5° south, the northeast and southeast trade winds converge in a low pressure zone known as the Inter-Tropical Convergence Zone or ITCZ. Solar heating in the region forces air to rise through convection which results in a plethora of precipitation. The ITCZ is a key component of the global circulation system.
What is predictive windshear detection mode? The weather radar processor detects the presence of a microburst, (a type of vertical wind shear condition) by detecting the Doppler frequency shift caused by the microburst and displays the area where it is present in the Navigation Display Unit of the EFIS. The system is activated automatically on the ground when the thrust levers are set to take off position. It scans 5nm ahead and gives warnings at 3nm. On approach, below 370ft, Warnings are downgraded to Cautions. Below 50 ft, notifications are inhibited.
Explain EGPWS? Enhanced Ground Proximity Warning System (EGPWS) is a system designed to alert pilots if their aircraft is in immediate danger of flying into the ground or an obstacle.
What are the inputs to EGPWS? Position
Airspeed / Mach number
Landing gear and flap position
Internal Terrain/Obstacles/Airport Databases
EGPWS vs. GPWS? EGPWS constitutes exactly the same warnings and modes as conventional GPWS.
In an aircraft capable of supplying the system with Present Position (IRS, GPS or GPIRS derived) then it provides two additional modes TCF and TAD. Both these are calculated by comparing PPOS to an internal terrain database and then giving the appropriate warning which above conventional GPWS is augmented by a visual warning, usually on the Navigation Display (ND). (by implication an aircraft capable of providing PPOS in the format required will have an EFIS system)
TCF Terrain Clearance Floor creates an increasing terrain clearance floor around the intended runway. Warning is “TERRAIN TERRAIN” visual
TAD Terrain Awareness and Display operates full time and used Aircraft position, altitude and a Terrain data base to predict conflicts between the aircraft flight path and the terrain.
Graphic displays of the terrain are available for display on the Navigation Display. Throughout all phases of flight Terrain clearance envelopes are monitored and if there is a conflict then a warning is issued. “TERRAIN TERRAIN” Visual. EGPWS is based on the AIRBUS application.
Can EGPWS work without GPS? Yes (It can get position information from another source like IRS, INS)
Where do hurricanes, cyclones and typhoons form? What direction do they track? Hurricanes and typhoons only can form over large basins of warm water such as an ocean or sea. This is due to the fact that they need a large amount of energy which is supplied by the heat from the warm ocean waters evaporating into the atmosphere. They also occur at least several degrees away from the equator. This is because the Coriolis force is too weak at the equator to generate spin for the hurricane. (Weak in the Intertropical Convergence Zone). They all track Westward/NorthWestward.
Northwest Pacific Ocean Typhoon season: This is the most active basin in the world. Most typhoons form between July and November. These can affect the Philippines, Southeast Asia including China and Taiwan, and Japan.
What are considerations when landing near a Typhoon? Windshear and turbulence will be expected
- Alterations to approach speeds and/or flap settings
Lower visibility and illusions with rain on the windscreen
Wet runway or has standing water
Possible delays in landing due to ATC or others having a difficult time on the ground
What causes wingtip vortices? Wingtip vortices are tubes of circulating air which are left behind a wing as the high pressure from the bottom of the wing goes around the wingtip to try to get to the low pressure on top.
Why use winglets? Reduction of Induced Drag from wingtip vortices. Winglets also provide the effect of increased aspect ratio without extending the wingspan.