How often are METARs issues?
Every hour, or whenever the weather changes and necessitates a change. In that situation, a SPECI (special METAR) is issued.
What is a SPECI?
A special METAR which is created in between the hourly METARs due to a change in weather necessitating the change.
Do METARs describe actual or forecast conditions?
METARs depict actual field conditions.
Define Radiation fog
Shallow fog, ground fog. occurs on clear nights, little or no wind, and small temp/DP spread (high relative humidity). Occurs at night or daybreak. Radiation cools the ground. The ground cools the air. When the air is cooled to the dew-point, fog forms.
Define Advection fog
This fog forms when moist air moves over colder ground or water. Common along the coast.
What is lake effect? Describe one major consequence of lake effect in winter.
Air moving across a sizeable lake absorbs water vapor.
Showers may appear on the leeward side if the air is colder than the water. If the air is warmer than the water, fog often develops on the leeward side. In the winter, lake effect snow is a concern because as a cold front passes over the warmer lake water, snow, instead of showers will occur.
What happens when the Temperature/dewpoint are very close?
Small Temp/DP spread is essential to the formation of fog.
How often are TAFs issued?
Valid for a 24-hour period, TAFs are issued four times daily at 00Z, 06Z, 12Z, and 18Z, and updated as conditions warrant. TAFs include information about wind speed and direction, visibility, present weather, ceilings, and low-level wind shear.
Why is it important to know when the various charts and reports are issued?
Because you always need to use the most up to date information and knowing when the next forecast is coming up is essential for making critcal flight decisions. For instance, if it is 05:55Z, the TAF from 00Z is the most up-to-date forecast, however, in only 5 minutes, the 06Z TAF will be the most up-to-date forecast and could contain critical information.
What is an Amended TAF?
An amended TAF is issued when the current TAF no longer adequately describes the ongoing weather or the forecaster feels the TAF is not representative of the current or expected weather.
Which sky conditions are considered a ceiling?
Broken, Overcast, VV (vertical visibility[indefinite ceiling])
How often is a surface analysis chart issued?
starting at 00Z at 3 hour intervals. (8 times a day)
What are the primary features of a surface analysis chart?
They show pressure patterns, fronts, and information on individual reporting stations. The pressure patterns are shown by isobars.
How is a surface analysis chart used?
It is used to determine sky cover, the types of clouds. SLP, pressure change, precip, temp/dew point, present wx, wind. They can be used to locate the jetstream, turbulence, and wind shear.
What is the relationship between isobars and surface winds?
The closer the isobars are together, the stronger the winds will be.
How often is a Weather depiction chart issued?
Every 3 hours
What is a weather depiction chart?
A weather chart to be used for flight planning by giving an overall picture of the WX across the US.
What is a Radar summary chart?
A radar summary chart is a graphically depicted collection of radar weather reports.
Does the Radar summary chart depict forecast conditions, or observed conditions? How often?
Observed, hourly.
What specific information is depicted by the symbols and graphics?
fix
it displays areas of precip, height of tops, movement of cells, type of precip, echo config, wx watches (severe wx)
What is the difference between visible and infrared Satellite imagery?
The visible images display cloud cover. The infrared images display the earth in a manner that correlates with temperature. Generally speaking, the warmer an object, the more infrared energy it emits.
What does water vapor imagery show on the Satellite imagery?
The water vapor images display the earth in a manner that correlates to quantity of water vapor in the upper portions of the atmosphere (25,000 feet and higher in general). The most useful information to be gained from the water vapor images is the locations of storm systems and the jet stream.
What do the Valid Times indicate?
(on a prog chart)
12 and 24 hours. They indicate that the prog chart is valid for 12 hours from the time issued, or 24 hours from the time issued.
How many times are Prog charts issued?
4 times a day. 00Z, 06Z, 12Z, 18Z.
Is a prog chart a forecast or a depiction of actual conditions?
Forecast.
Remember “to prognosticate” means “to forecast”
What kinds of weather/hazards are shown on the low level prog chart?
Precip, icing, turbulence, thunderstorms, tropical storms, hurricanes IFR/MVFR conditions, areas of high/low pressure, different types of fronts.
What is a cold front?
The leading edge of an advancing cold air mass
What clouds are associated with a cold front?
Cumulus and cumulonimbus
What weather is associated with a cold front?
Thunderstorms, hail, tornadoes
What discontinuities are associated with a cold front?
-Temp: Cold air advances and overtakes warm air.
-Dewpoint:
-Wind: They move at about the speed of the wind component perpendicular to the front just above the frictional layer.
-Pressure: Pressure usually rises abruptly.
What is a warm front?
The leading edge of an advancing warm air mass.
What clouds are associated with a warm front?
Stratus clouds. Nimbostratus, altostratus, cirrostratus, cirrus.
What type of weather is associated with a warm front?
Continuous rain, Drizzles
What type of weather is associated with a stationary front?
Several days of overcast weather (stratus clouds) and drizzle, nothing severe.
What type of front is associated with a temperature inversion?
A cold front. This is because the advancing cold airmass sinks below the warm airmass and pushes the warm airmass up above the cold airmass. This creates an inversion because the warm air will be above the cold airmass and therefore temperature will increase as altitude increases.
An occluded front is also associated with a temperature inversion for the same reason.
What is a temperature inversion?
A temperature inversion is when temperature increase with altitude rather than decrease with altitude. Inversions are common in the stratosphere.
What is an airmass?
a volume of air defined by its temperature and water vapor content. Air masses cover many hundreds or thousands of square miles, and adapt to the characteristics of the surface below them. They are classified according to latitude and their continental or maritime source regions.
What weather is associated with a warm front?
continuous rain and drizzle
What discontinuities are associated with a warm front?
-Temp: Warm air
-Dewpoint:
-Wind:
-Pressure: Pressure usually drops abruptly.
What is an occluded front?
an occluded front is a front that is made up of 3 air masses. 2 cold air masses (cold and cool), and one warm air mass. All the air masses are all moving in the same direction.
How and why does a temperature inversion occur in an occluded front?
A temperature inversion occurs in an occluded front because the cold air masses push the warm air mass up and above them, therefore warmer air will exist as altitude increases.
What is a stationary front?
A stationary front is when an advancing warm airmass and an advancing cold airmass converge and one is not strong enough to overtake the other so the air masses become stationary.
What is an Isobar?
An Isobar is a line of equal pressure reduced to sea level. Since pressure varies with altitude, we cannot readily compare station pressures between stations at different altitudes. To make them compatible with each other, we must adjust them to a common level (MSL)
What is standard sea level pressure in
-millibars
-inches of mercury
-millimeters of mercury
-PSI
1013.2 -millibars
29.92 -inches of mercury
760 -millimeters of mercury
14.7-PSI
What is a strong pressure gradient (closely spaced isobars) indicate?
High winds
What is Pressure Altitude?
For pressure altitude, set the window in your altimeter to 29.92. Whatever value it reads is pressure altitude.
What is Density Altitude?
pressure altitude corrected for non-standard temperature.
What is true altitude?
This is the height above “mean sea level”
What is absolute altitude?
Absolute altitude is your height above the ground.
Describe circulations associated with high pressure systems.
High pressure = clockwise circulations
(Anti-cyclones)
Describe circulations associated with low pressure systems.
Low pressure = counter-clockwise circulations
(Cyclones)
How often are SIGMETs and AIRMETs issued?
While in effect, they are issued at 15 minutes and 45 minutes past the hour.
What are SIGMETs?
A SIGMET is issued to alert pilots of potential hazardous WX not adequately issued in an area forecast.
- Severe and extreme turbulence
- Severe icing
- Widespread dust storms, sandstorms, or VA lowering visibility to below 3 miles.
What are AIRMETs?
An AIRMET is issued to alert pilots of potential hazardous WX not adequately issued in an area forecast.
-Moderate icing
-Moderate turbulence
-Sustained winds of 30+knots at the surface
-Widespread areas of ceilings less than 1,000 feet or visibilities of less than 3 miles.
- Extensive mountain obscurement.
What are convective SIGMETs?
A Convective SIGMET is issued to alert pilots of potential hazardous WX not adequately issued in an area forecast.
- Tornadoes
- Lines of T-storms
- Embedded thunderstorms
- T-storms areas greater or equal to intensity level 4
- Hail greater than 3/4 of an inch in diameter
What is an area forecast? (FA)
Expected VMC, clouds, and general WX conditions over an area the size of several states. FA’s should be used in conjunction with AIRMETs SIGMETs, and convective SIGMETs to get a full picture.
What locations are SIGMETs issued for?
SFO – San Francisco
SLC – Salt Lake City
DFW – Dallas Fort Worth
MIA – Miami
CHI – Chicago
BOS – Bostone
What are the three types of AIRMETs?
Airmet Sierra (S) – (Mountain obscuration or IFR) ceilings less than 1000 feet and/or visibility less than 3 miles affecting over 50% of the area at one time; extensive mountain obscuration
Airmet Tango (T) – (Turbulence) – Light – moderate turbulence, sustained surface winds of 30 knots or more.
Airmet Zulu (Z) – (Icing) Light – moderate icing, freezing levels
What is the main difference between a SIGMET and an AIRMET?
SIGMETs should be considered as significant SEVERE hazardous weather. AIRMETs are light to moderate potential hazardous weather.
What are the three stages of a thunderstorm?
Cumulous, mature, dissipating
What are the two types of a PIREP?
Routine UA and urgent UUA.
What is an ATIS?
Automated Terminal Information System. A recorded message which tells pilots about the current conditions of the airport such as wx, and notams. Recorded hourly and a SPECI, special ATIS is issued for significant WX or information change ( closed runway/taxiway, change of active runways, special instruction etc.)
What is IFR? (Ceiling/visibility)
Instrument Flight Rules. less than 1000 ft ceiling and less than 3 miles visibility.
What is VFR? (Ceiling/visibility)
Visual flight rules. More than 1000 ft ceiling and 3 miles or greater visibility.
What is MVFR? (Ceiling/Visibility)
Marginal Visual Flight Rules. 1000ft – 3000ft ceiling and/or 3SM – 5SM visibility.
What are the three types of structural icing?
Rime, Clear, Mixed
Describe Rime Ice
Brittle and frost-like
Describe Clear ice
Hard, heavy, tenacious, and glossy. Hard to remove
Describe mixed ice
Hard rough conglomerate
Which is the most dangerous type of structural ice?
Because it is heavy, hard to remove, and sometimes difficult to detect until it is too late because it takes the shape of the surface area.
Under what conditions is structural ice likely to develop?
(1) The aircraft must be flying through visible water such as rain or or cloud droplets and (2) the temperature at the point where the moisture strikes the aircraft must be 0°C or colder.
Define Clear Air Turbulence (CAT)
Clear-air turbulence (CAT) is the turbulent movement of air masses in the absence of any visual cues such as clouds, and is caused when bodies of air moving at widely different speeds meet
Define wake turbulence
Wake turbulence is turbulence that forms behind an aircraft as it passes through the air. This turbulence includes various components, the most important of which are wingtip vortices and jetwash.
Which types of airplanes cause the most significant wake turbulence?
Slow, clean, and heavy.
What is LLWS? Why is it particularly dangerous?
Low Level Wind Shear. It is dangerous because it can cause
Why are thunderstorms so dangerous?
Because they can create many hazards for aircraft such as updrafts and downdrafts, hail, low visibility, precipitation, wind shear, lightning.
List and describe the three stages of a thunderstorm.
Cumulus (Updrafts)
Mature (Precipitation)
Dissipating (Downdrafts)
What is the difference between air mass thunderstorm and steady state thunderstorms?
Define squall line
A squall line is a line of thunderstorms that can form along or ahead of a cold front. The term was used as a synonym for cold front. It contains heavy precipitation, hail, frequent lightning, strong straight-line winds, and possibly tornadoes and waterspouts.
Define dry line
A dry line is a boundary that separates a moist air mass from a dry air mass. Also called a “Dew Point Front”, sharp changes in dew point temperature can be observed across a dry line.
What are 6 items required on a dispatch release?
1) Aircraft ID
2) Trip Number
3 Airports (Dep. Des. Interm. Alt.)
4) Type of Op. (IFR or VFR)
5) Min. Fuel Supply
6) Weather Reports
FAR 121.687
What is the minimum fuel supply for IFR domestic operations?
Enough fuel to fly to the destination. Then from there enough fuel to fly to the furthest alternate airport. Then have 45 minutes of fuel remaining.
FAR 121.643
Where must a B727 pilot land if he loses an engine? Find in FARs
A 727 has three engines. If a pilot loses one engine, the pilot may proceed to an airport he selects if he decides that proceeding to that airport is as safe as landing at the nearest airport.
FAR 121.565
What are three items that a pilot must carry onboard to the destination?
1) Completed Load Manifest
2) Dispatch Release
3) Flight Plan
FAR 121.695
What is operational control?
Exercising authority over initiating, conducting, or terminating a flight
In addition to the dispatch release, what are the other documents that must be carried aboard the airplane to the destination by the pilot?
Completed Load Manifest and the Flight Plan.
FAR 121.695
How is minimum fuel supply for a flight determined? What specific factors must be considered when computing minimum fuel?
Determine how much fuel you need to reach your destination.
Determine if you need an alternate airport due to potential low ceilings and low visibility at the time you reach your destination and determine the fuel required to fly to your furthest alternate from your initial destination airport.
Then determine how much fuel is required in order for you to fly an additional 45 minutes beyond reaching your furthest alternate at normal fuel consumption.
FAR 121.643
What are the limitations for listing a takeoff alternate for a B727? (Time distance limitations?)
What person(s) are responsible for operational control of each flight under Part 121 Domestic rules?
Describe those responsibilities shared by the dispatcher and the pilot in command.
What additional duties and responsibilities does the dispatcher have? What are the specific duties of the pilot in command? What regulation is referenced?
What is the maximum amount of consecutive hours an aircraft dispatcher can be scheduled for?
What is the difference between a precision and a non-precision approach?
A precision approach as both vertical and horizontal guidance to the runway (ILS). A non-precision approach only has horizontal guidance to the runway (VOR).
What are standard takeoff minimums? When can lower than standard takeoff minimums be used?
When is an alternate for the destination airport required? What rule is used to determine whether an alternate is required?
When does the dispatcher’s duty period end?
What are standard alternate minimums? When can lower than standard alternate minimums be used?
What is the maximum number of consecutive hours of duty for which a dispatcher can be scheduled? Can a dispatcher be scheduled for more than 10 hours in a 24 hour period? If so, how?
What is the first thing a dispatcher should do at the start of a duty period?
What are “high minimums”? What weather do they apply to (exp. departure, destination, alternate?
How many flight attendants are required for the B727? Find in FARs
What are the four components of an ILS approach?
Can a dispatcher ever be scheduled for more than 10 hours in a 24 hour period? If so, how?
How does a VOR work?
Under what circumstances is a takeoff alternate required? What requirements must be met in order to list an airport as a takeoff alternate?
How does an NDB work?
How does GPS work?
Which altitudes is an IFR Low Enroute chart used for?
SFC up to but not including 18,000ft
As a dispatcher, what course of action do you have to take if the original alternate that you listed on the dispatch release goes below alternate minimums while the aircraft is enroute?
Which altitude is an IFR high altitude chart used for?
18,000 ft (FL180) – FL600
What is a MEA?
MEA= Minimum enroute altitude
What is a MOCA?
MOCA = Minimum obstacle clearance altitude
What is the operational service volume of a high VOR?
H (High Altitude) From 1,000 feet AGL up to and including 14,500 feet AGL at radial distances out to 40 NM. From 14,500 AGL up to and including 18,000 feet at radial distances out to 100 NM. From 18,000 feet AGL up to and including 45,000 feet AGL at radial distances out to 130 NM. From 45,000 feet AGL up to and including 60,000 feet at radial distances out to 100 NM.
What is the operational service volume of a low VOR?
T (Terminal) From 1,000 feet above ground level (AGL) up to and including 12,000 feet AGL at radial distances out to 25 NM.
L (Low Altitude) From 1,000 feet AGL up to and including 18,000 feet AGL at radial distances out to 40 NM.
How many hydraulic systems does the B727 have? What are they?
Two. System A and System B.
What does hydraulic System A power?
- Ground spoilers
- Outbound Flight Spoilers
- Ailerons
- Elevators
- Brake Interconnect Valve
- Main gear brakes
- Trailing edge devices
- Leading edge devices
- Gear actuation
- Tail skid
- Nose gear steering
What is the main source of electrical power for the B727?
The airplane has three engine-driven generators that provide AC power.
What is the back-up source of electrical power for the B727?
The battery will provide emergency electrical power for up to 25 minutes if the primary systems fail
As an aircraft dispatcher, what considerations do you need to make if the APU is inop?
Make sure that external electrical and pneumatic power (GPU/Air start) are available at all airports of intended operation
What is a Constant Speed Drive?
Constant Speed Drive–Converts variable engine speed (RPM) to a steady speed (RPM) for the generator.
How many fuel tanks does the B727 have? How much fuel does each tank hold?
Three. Tanks 1 and 3 can each hold 12,000lbs, Tank 2 can hold 27,500lbs
What is the max structural takeoff weight for the B727?
What is the max
structural landing weight for the B727?
What is the zero fuel weight for the B727?
What are V1, Vr, and V2?
How does the use of engine anti-ice affect performance?
Define “accelerate stop distance”.
The length of the takeoff run plus the length of the Stopway, where provided.
What is an MEL?
Minimum equipment list. A list which states which equipment must be operation in order for a flight to proceed.
What is a CDL?
What is an APU? What is it used for?
Electricity and air conditioning on the ground, and air and electricity for starting the engines.
How does an anti-skid inop effect performance?
How are landing minimums affected if the pilot in command has fewer than 100 hours as pilot in command of the particular type airplane to be flown? What is the specific regulation that applies? Does this also apply to the alternate minimums?
Who is normally responsible to declare an emergency, should it be necessary to do so?
If a dispatcher knows of a situation requiring immediate action, what should he/she do first?
What kind of information is contained in D NOTAMs?
When should the dispatcher declare an emergency?
With whom must the pilot in command have two-way communications along the entire route for each flight?
What is the purpose of NOTAMs?
What are FDC NOTAMs?
How does the pilot identify the MAP during a non-precision approach?
Where are the Jet routes located (altitudes)?
Where are the Victor Airways found (altitudes)?
How does the pilot identify the Final Approach Fix (FAF) on a precision approach such as the ILS?
How does the pilot identify the Missed Approach Point on a precision approach such as the ILS?
How is the final approach fix depicted on the approach plate diagram for a non-precision approach?
What requirements must be met in order to operate in RVSM airspace?
How is the missed approach point depicted on the approach plate for a non-precision approach?
How can the dispatcher determine whether RVSM operations are permitted?
How can the dispatcher determine which kinds of navigation systems can be used for a flight?
Are air carriers required to use preferred routes when filing flight plans?
What altitude range is covered by the High Altitude En Route Charts?
What is MEL? What is CDL? Explain the purpose of MEL and CDL
What is RVSM?
What items are powered by the A system hydraulics?
What items are powered by the B system?
Where are preferred IFR routes found?
Who makes the engines for B727? What model engine?
What altitude range is covered by the Low Altitude En Route charts?
What factors affect takeoff performance?
When do icing conditions exist on the ground, according to Boeing?
How are engine and wing anti-ice accomplished (what is the source of heat)?
If an item becomes inoperative in flight, do you check the MEL? What manual should be consulted?
When is engine anti-ice required to be turned on for takeoff?
What type of deice/anti-ice systems does the 727 have?
Is there a backup if all generators fail? What is it, and how long will it last?
How do the brakes work in the event of a B system failure?
If both the A and B systems fail, how are the primary flight controls operated?