Aircraft Dispatcher O&P
Other considerations: Runway Conditions
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5) Do I need a Destination Alternate? (FAR 121.619)
*1,2,3 Rule* No person may dispatch under IFR or over the top unless he lists at least one alternate for ea. destination airport in the dispatch release. When wx conditions forecast for the destination and first alternate airport are marginal at least one additional alternate must be designated. However, no alt airport is required if for at least 1 hour before and 1 hour after the ETA at the destination airport the appropriate wx reports or forecasts, or any combo of them indicate - - the ceiling will be at least 2,000 ft above airport elevation and, - visibility will be at least 3 miles ((Do we need a back up plan? Look at TAF one hour before and one hour after ETA))
What are causes of temperature variations across the planet?
-diurnal variation -seasonal variation -latitude [angle of sun exposure] Topographical issues Altitude effects
2) Can I take off? (FAR 121.651 or 91.175) *(97.3)
1. OPS Specs 2. 91.175 (f) Civil Airport Takeoff minimums- Pilot can't take off under IFR unless wx conditions at time of takeoff are at or above the wx minimums for IFR. If takeoff wx mins are not prescribed under part 97 for particular airport, the following wx mins apply: 2 engines or less - 1 SM visibility. Aircraft having more than 2 engines: 1/2 SM visibility. Helicopters: 1/2 SM visibility 3. 121.651 (a)- No pilot may begin takeoff in an airplane under IFR when wx conditions reported by US National Weather Service, a source approved by that service, or a source approved by the Administrator, are less than those specified in (i) the certificate holders ops specs (ii) Parts 91 and 97 if the ops specs do not specify takeoff mins for the airport *97.3 - aircraft approach category
6) Does Destination ALT meet wx mins? (FAR 121.625)(FAR121.619)
121.625 - No person may list airport as alt in dispatch unless the appropriate wx reports or forecasts indicate the wx conditions will be at or above the alt wx minima specified in OPS SPECS for alternate 121.619 - *1,2,3 Rule* *91.169 (c)* - IFR alt airport weather minima. (A) For precision approach procedure, ceiling 600 ft and visibility 2 SM (B) For non precision approach procedure, ceiling 800 feet and visibility 200 SM
What is standard temperature at sea level?
15*C or 59*F
What is the standard temperature lapse rate?
2 degrees C for every 1000 ft of altitude
What is the standard atmosphere?
29.92 hg or 1013.2mb This is a standard construct model of the Earth's atmosphere in terms of temperature and pressure. Simply it is an average of atmospheric conditions.
What is the gas composition of the atmosphere?
78% nitrogen 21% oxygen 1% other gases, including water vapor
What is TCAS III?
A TCAS that utilizes interrogation of, and replies from, airborne radar beacon transponders and provides traffic advisories and resolution advisories in the VERTICAL AND HORIZONTAL planes to the pilot.
What is a col?
A col is a neutral area between high and low pressure systems, or it is where a ridge and a trough meet
What is a GS?
A glideslope Is an electronically produced vertical guidance system used by aircraft during landing. GS can also be used to represent aircraft ground speed
What is a "flight level"? When is the term used?
A level of constant atmospheric pressure related to a reference datum of 29.92 inches of mercury. Cruise altitudes of aircraft are referred to as flight levels above 17,999 feet. FL 180
What is "area navigation" - RNAV-?
A method of navigation that permits aircraft operations on any desired flight path Means of navigation that allows for direct and random routes. Ex) GPS, DME, VOR/DME
What are some examples of crewmembers?
A person assigned to perform duty in an aircraft during flight time. Ex) flight attendants, pilots
What is a ridge?
A ridge is an elongated area of high pressure
What is an "instrument approach procedure" [IAP]?
A series of predetermined maneuvers by reference to flight instruments with specified protection from obstacles and assurance of navigation signal reception capability. Can be used any time but are intended to assist in landing during poor weather conditions
What is a "precision approach"? Name some examples.
A standard instrument approach procedure in which an electronic glide slope is provided, such as ILS [instrument landing system - localizer and glideslope] and PAR [precision approach procedure]
What is a "non-precision approach"? Name some examples of this type of procedure.
A standard instrument approach procedure in which no electronic glide slope is provided. Ex) VOR, NDB, localizer, GPS
What is a "long range communication system" [LRCS]? What are two examples of this type of system?
A system that uses satellite relay, data link, high frequency, or another approved communication system which extends beyond line of sight
Define AGL
Above ground level the height of an aircraft above the ground. Also referred to as absolute alittude
What is indicated altitude?
Aircrafts height based on the altimeter reading in the cockpit
What is an AFM?
Airplane Flight Manual An instruction manual for how to operate a particular aircraft
What is the definition of "controlled airspace"?
Airspace of defined dimensions within which air traffic control service is provided to IFR flights and to VFR flights in accordance with the airspace classification. Controlled airspace is a generic term that covers Class A, Class B, Class C, Class D, and Class E airspace
At what altitude is hypoxia typically considered to be a factor?
Although effects of hypoxia may occur at a lower altitude, 10,000 ft.
The altimeter setting in Denver is reported at 30.00 HG, what is actual atmospheric pressure at station?
Altimeter settings are reduced to sea level. Actual barometric pressure is around 25.00" hg because atmospheric pressure in Denver is 5" less since it is 5000 feet above sea level.
What is pressure altitude?
Altitude in reference to standard datum plane of 29.92. When aircraft altimeter is set to 29.92 Hg, it reads pressure altitude. Aircraft fly at pressure altitude at and above 18,000
What is the definition of an "alternate airport"?
An airport at which an aircraft may land if a landing at the intended airport becomes inadvisable
What is a "stopway"?
An area beyond the takeoff runway, no less wide than the runway and centered upon the extended centerline of the runway, able to support the airplane during an aborted takeoff, without causing structural damage to the airplane, and designated by the airport authorities for use in decelerating the airplane during an aborted takeoff. 121.189 - in calculating your accelerate stop distance available -ASDA- you can take stopway into consideration
What is an "air traffic control clearance"?
An authorization by air traffic control, for the purpose of preventing collision between known aircraft, for an aircraft to proceed under specified traffic conditions within controlled airspace
What is "long range navigation system" [LRNS]?
An electronic navigation unit that is approved for use under instrument flight rules as a primary means of navigation, and has at least one source of navigational input, such as inertial Navigation system [INS] or Global Positioning System [gps] Out of range of typical ground based NAV sources
What is a trough?
An elongated area of low pressure. Weather systems often develop in association with troughs.
What is an "enhanced flight vision system" (EFVS)?
An installed aircraft system which uses an electronic means to provide a display of the forward external scene topography [the natural or man made features of a place or region, especially in a way to show their relative positions and elevation] through the use of imaging sensors, such as forward looking infrared, millimeter wave radiometer, millimeter wave radar, and low light level image intensifier.
What is considered an extended overwater operations?
An operation over water at a horizontal distance or more than 50 nautical miles from the nearest shoreline
Define ALS
Approach Light System Used to guide aircraft from an area off the end of the runway to the threshold and is typically used in poor weather or at night
What effect does temperature have on aircraft performance?
As temperature increases, aircraft performance is reduced due to a decreases in air density
How does wind flow in relation to isobars near the surface? Why?
At the surface, winds tend to flow perpendicular to isobars as a result of frictional forces
What is an APU?
Auxiliary power unit Miniature jet engine, usually in the tail of a transport aircraft, that is used for electric and/or bleed [pneumatic] air on the Bourne and in the air - typically in emergency or abnormal situations
What affects density altitude?
Density altitude changes with temperature, pressure, and humidity. As temperature increases, density altitude increases. As pressure decreases, density altitude increases. As humidity increases, so does density altitude.
What is density altitude?
Density altitude is the altitude the aircraft "thinks" it is flying. Aircraft will perform as though it is at the current density altitude regardless of the actual altitude at which it is flying.
Standard temperature at the airport of departure is 10* C. The ambient temperature is 15*C. What is true about density altitude and aircraft performance on this day?
Density altitude will be higher than field elevation and aircraft performance will be reduced
What is DME?
Distance measuring equipment Used to determine how far an aircraft is flying from a particular NAVAID. GPS can be used as a substitute for DME under certain circumstances. DME is a requirement for flights above FL240 in the US.
What is diurnal variation?
Diurnal variation is the differences in temperature caused by daytime heating versus nighttime cooling
Why is wind speed usually slower near the surface as compared to aloft?
Due to friction between the terrain at the surface and the wind.
Why does high density altitude reduce aircraft performance?
Due to the reduction in the number or air molecules in a given volume of air -reduced density- such conditions: Reduce engine thrust/power Reduce the amount of lift that is produced by the wing
How does wind flow locally in mountain/valley regions during the day? At night?
During the day, air along mountain slopes warms, forcing winds to flow up from the valley -valley wind- At night, the air aloft cools and then sinks, moving from the mountains into the valley. This is known as mountain wind -katabatic wind-
What is ETOPS?
Extended Operations. An airplane flight operation, other than an all-cargo operation in an airplane with more than two engines, during which a portion of the flight is conducted beyond a time threshold identified in 121 or part 135 that is deterred using an approved one-engine-inoperative cruise speed under standard atmospheric conditions in still air.
What is a "clearway"?
For turbine aircraft built after August 29, 1959 , the clearway is an area beyond the runway, not less than 500 feet wide, centrally located about the extended centerline of the runway, and under the control of the airport authorities. The clearway is expressed in terms of a clearway plane, extending from the end of the runway with an upward slope not exceeding 1.25% , above which no object nor any terrain protrudes. For aircraft built before this date, the clearway must be 300 feet wide and have no obstacles 121.189 - In determining Acccelerate Stop Distance Available [ASDA] you can take clearway into consideration
What are some examples of RNAV capable avionics?
Global Positioning System -GPS-, flight management system -FMS-, distance measuring equipment -DME-, and VOR/DME RNAV
What is HIRL?
High intensity runway light systems Very bright lights that line the edge of the runway
Describe a high pressure system
Highs are areas of increased pressure and have clockwise wind that flows outward and downward in northern hemisphere. These tend to be associated with good weather
1) Do I have a High Mins (Baby) Capt? (FAR 121.652)
If PIC<100 hours as PIC in Aircraft Type the MDA (minimum descent altitude) and DH (Decision Height) {destination/landing} will be increased 100 ft and +1/2 SM -This does not apply to alternate; however, minimums must never be less than 300 ft or 1 SM
3) Do I need a take-off Alt? (FAR 121.617)
If wx conditions at the airport of takeoff are below landing minimums in certificate holders ops specs for that airport, can't dispatch aircraft from that airport unless the dispatch or flight release specifies an alternate airport located within the following distances from the airport of takeoff: 1) Aircraft having 2 engines: Not more than 1 hour from departure airport at normal cruising speed in still air with 1 engine inoperative 2) Aircraft having 3+ engines: Not more than 2 hours from the departure airport at normal cruising speed in still air with 1 engine Inoperative
What are some common units used to measure or present atmospheric pressure?
Inches of mercury (Hg) Millibars (mb) Hectopascals (hPA)
What is the ICAO?
International Civil AViation Organization International entity that aims to help standardize aviation operations in a global environment. It's objectives are to augment safety, security, environmental protection, efficiency, continuity, and rule of law
What potential issues might arise when an inversion exists at an airport?
Inversions often are associated with reduced visibility and possible wind shear as an aircraft passes through the inversion layer.
Where is the tropopause the thickest - at the poles or at the equator?
It is thickest at the equator where it stretches to 55,000 to 65,000 feet. At the poles it only extends up to 25,000 to 30,000. In mid latitudes it is around 35,000 to 40,000 feet
What is an isobar
Line of equal pressure
Describe low pressure system
Lows are areas of reduced pressure and have counterclockwise wind that flows inwards and upwards in the northern hemisphere. Associated with poor weather.
Other Considerations: Winds
MAX takeoff and landing tailwind = 10KTS Max Xwind =36 KTS (737-800 No Winglets)
Define Vmo/Mmo
Maximum operating limit speed
Define V1
Maximum speed in the takeoff at which the pilot must take the first action to stop the airplane within the accelerate-stop distance. It is also the minimum speed in the takeoff, following a failure of the critical engine at Vef, at which the pilot can continue the takeoff and achieve the required height above the takeoff surface within the takeoff distance.
What is TCAS II?
Means a TCAS that utilizes interrogations of, and replies from airborne radar beacon transponders and provides traffic advisories and resolution advisories in the VERTICAL plane.
What is the definition of an "air carrier"
Means a person who undertakes directly by lease, or other arrangement, to engage in air transportation
What is the definition of "air commerce"?
Means interstate, overseas, or foreign air commerce or the transportation of mail by aircraft or any operation or navigation of aircraft within the limits of any Federal airway or any operation or navigation of aircraft which directly affects, or which may endanger safety in, interstate, overseas, or foreign air commerce
What is an "MDA"?
Minimum descent altitude - is the lowest altitude specified in an instrument approach procedure, expressed in feet above mean sea level, to which descent is authorized on final approach or during circle-to-land maneuvering until the pilot sees the required visual references for the heliport or runway of intended landing.
8)What else do you check?
NOTAMS & Notes on Flight Plan Trip Sheet
4) Can I dispatch to Destination? (FAR 121.613)
No person may dispatch for operations under IFR or Over-the-Top, unless appropriate wx reports or forecasts, or any combination thereof, indicate that the wx conditions will be at or above the authorized minimums at the ETA @ the airport or airports to which dispatched......... ((Check wx @ destination airport + compare it to landing minimums there. You look @TAF and landing minimums @ or above minimums you can't land if its lower than minimum, you have to delay or cancel flight))
7) Do I have MELS? 121.628
No person may take off an airplane with inoperable instruments or equipment installed unless: (1)an approved minimum equipment list exists for that airplane
What is wind shear?
Occurs any time there is a rapid shift in wind speed or direction.
Why is operational control important?
Operational control ensures that aircraft are operated under safe conditions and are monitored throughout a flight. The FAA also requires that flights always remain under control of the company operating them. Flights must always be able to be communicated with by dispatch in order to guarantee these aforementioned provisions.
What is operational control?
Operational control is the authority to initiate, conduct, and terminate a flight.
How does pressure vary with altitude?
Pressure decreases as altitude increases. In the standard atmosphere the rate of decrease is 1 inch Hg per 1,000 feet
What determines the speeds of wind?
Pressure gradient force or how much pressure changes over a given distance. Closely spaced isobars have a strong pressure gradient - quick change over small area- and will have strong wind
Define VR
Rotation speed during takeoff
Other Considerations: Airport Analysis (121.189)
S- Structural Limit (never exceed max takeoff weight) F- Field Length* C- climb capability* O- obstacle clearance* T- tire speed* B- brake energy* *all changeable by other factors (weight, altitude, temp)
What is a "flight plan"?
Specified information, relating to the intended flight of an aircraft, that is filled orally or in writing with air traffic control. Includes: departure airport, destination airport, route of flight, estimated time of departure, estimated time enroute, flight rule type [IFR/VFR] , and fuel onboard.
What is an "air traffic service -ATS- route"?
Specified route designated for channeling the flow of traffic as necessary for the provision of air traffic services. The term "ATS route" refers to a variety of airways, including jet routes, area navigation -RNAV- routes, and arrival and departure routes. An ATS route is defined by route specifications which may include : 1. An ATS route designator 2. The path to or from significant points 3. Distance between significant points 4. Reporting requirements 5. The lowest safe altitude determined by the appropriate authority
Define V2
Takeoff safety speed. Airspeed that will allow an aircraft to continue a takeoff with a positive slope [be able to climb]. This speed must be achieved by an altitude of 35 feet no later than reaching the departure end of the runway.
What is Coriolis force?
The Coriolis force a phenomenon that occurs due to rotation of the Earth that causes wind in the Northern Hemisphere to be deflected to the right
What is true airspeed?
The airspeed of an aircraft relative to undisturbed air. In a no-wind condition, TAS will equal ground speed.
How is the critical engine determined in an aircraft?
The engine whose failure would most adversely affect the performance or handling qualities of an aircraft. Most twin-engine jet aircraft have no critical engine as the failure of either engine has identical effects. In four-engine jet aircraft, the outboard engines are considered critical because the failure of one will cause a larger yaw moment than the failure of an inboard engine.
What is the definition of a "ceiling" in terms of weather reporting?
The height above the earth's surface of the lowest layer of clouds or obscuring phenomena that is reported as "broken," "overcast," or "obscuration."
What is the definition of the term "pilot-in-command"?
The person who: 1. Has final authority and responsibility for the operation and safety of the flight 2. Has been designated as pilot in command before or during the flight 3. Holds the appropriate category, class, and type rating, if appropriate, for the conduct of the flight
High altitude flight planning airspeeds are given as Mach numbers. How is Mach number defined?
The ratio of true airspeed to the speed of sound. The true airspeed [TAS] of an aircraft increases as altitude increases. The speed of sound decreases as temperature decreases [which occurs with increases in altitude]. Thus, TAS and Mach converge as an aircraft climbs. If a constant indicated airspeed [IAS] is held as an aircraft climbs, Mach number will gradually increase.
Define Vef
The speed at which the critical engine is assumed to fail during takeoff
Sea breeze vs land breeze
The wind will blow from the higher pressure over the water to lower pressure over the land causing the sea breeze. The sea breeze strength will vary depending on the temperature difference between the land and the ocean. At night, the roles reverse. The air over the ocean is now warmer than the air over the land.
What is the difference between a decision altitude [DA] and a decision height [DH]?
They both are a specified height above the gourd in an instrument approach procedure at which the pilot must decide whether to initiate an immediate missed approach if the pilot does not see the required visual reference or to continue the approach. Decision altitude is expressed in feet above mean sea level. Decision height is expressed in feet above ground level
What is true altitude?
True altitude - height above sea level
Which type of topographical surface will heat up faster? A Ploughed field or a swamp?
Typically, dry objects will heat up faster thus the field will heat up more quickly than the swamp.
What is primary cause of all weather?
Uneven heating of the Earth's surface
What causes wind?
Uneven heating of the earth's surface
What does it mean if an airport or an aircraft is said to be experiencing IFR conditions?
Weather conditions below the minimum for flight under visual flight rules. An airport is considered to be IFR when the weather is reported to be less than 3 SM visibility and the ceiling is less than 1,000 feet
When is the operation of aircraft considered to be flight time?
When an aircraft is first moved under its own power for the purpose of flight until it comes to a rest after landing
What is a Category II ILS? [AIM 1-1-9]
With respect to the operation of aircraft, means a straight-in ILS approach to the runway of an airport under a Category II ILS instrument approach procedure issued by the Administrator or other appropriate authority Category II- DH 100 feet and RVR 1,200 feet. Limitation DH 150 feet and RVR 1,600 until 3 approaches have been made in 3 months
What are the different types of Category III ILS approaches and what minimums are associated with each type? [AIM 1-1-9]
With respect to the operation of the aircraft, means an ILS approach to and landing on, the runway of an airport using a Category III ILS instrument approach procedure issued by the Administrator or other appropriated authority IIIa. Approaches allow operations down to a DH as low as 100 feet and to an RVR as low as 700 feet. IIIb. Approaches allow operations down to a DH as low as 50 feet and to an RVR between 700 feet and 150 feet IIIc. Operations are permitted without a DH or visibility requirement
Weather maps often refer to height contours. What do they describe?
Wx maps use isobars to connect areas of equal pressure height (contours) to indicate pressure systems. -like topographical maps-
What is hypoxia?
deficiency in the amount of oxygen reaching the tissues
What is an inversion?
temperature increases with height
What is Katabatic wind
wind flowing along an inclined surface. This is common in mountainous areas and is caused by cold, dense air aloft rapidly sinking downwards along sloping terrain
