01/2021 Flashcards
1
Q
RNAV
A
- Area Navigation (RNAV) is a key enabler of Performance Based Navigation (PBN). It is a family of navigation specifications which permit the operation of aircraft on any desired flight path; RNAV allows aircraft positions to be continuously determined wherever the aircraft are within the coverage of navigation aids.
- (GPS), brought a new opportunity to derive an accurate three-dimensional (VNAV) position as well as a highly accurate two-dimensional (LNAV) position over an area not restricted by the disposition of ground transmitters.
- RNAV of sufficient accuracy is seen as ultimately providing a replacement for all ground-based navigation aids.
- (ICAO) PBN Manual identifies four navigation specifications under the RNAV family: RNAV 10, RNAV 5, RNAV 2 and RNAV 1.
- RNAV 10, designated as RNP 10 in the ICAO’s PBN Manual, is an RNAV specification for oceanic and remote continental navigation applications.
- RNAV 5, also referred to as Basic Area Navigation (B-RNAV), has been in use In Europe since 1998 and is mandated for aircraft using higher level airspace. It requires a minimum navigational accuracy of +/- 5nm for 95% of the time and is not approved for use below MSA.
- RNAV 2 supports navigation in en-route continental airspace in the United States.
- RNAV 1 is the RNAV specification for Precision Area Navigation (P-RNAV). It requires a minimum navigational accuracy of +/- 1nm for 95% of the time.
- Under the PBN concept, in addition to RNAV navigation specifications there exists the required navigation performance (RNP) family of navigation specifications. RNAV and RNP navigation specifications are substantially very similar; they only differ in relation to the performance monitoring and alerting requirement which applies to RNP navigation specifications. This means that if the RNP system does not perform the way it should then an alert should be provided to the flight crew.
2
Q
PBN
A
- It is a new concept based on the use of Area Navigation (RNAV) systems.
- ICAO PBN Manual (Doc 9613) definition is: Area navigation based on performance requirements for aircraft operating along an ATS route, on an instrument approach procedure or in a designated airspace.
- PBN represents a fundamental shift from sensor-based to performance-based navigation and offers a number of advantages over the sensor-specific method of developing airspace and obstacle clearance criteria, i.e.:
- reduces the need to maintain sensor-specific routes and procedures, and their associated costs;
- avoids the need for developing sensor-specific operations with each new evolution of navigation systems, which would be cost-prohibitive;
- allows for more efficient use of airspace (route placement, fuel efficiency and noise abatement);
- clarifies how RNAV and RNP systems are used; and
- facilitates the operational approval process for operators by providing a limited set of navigation specifications intended for global use.
- Currently, the PBN approach procedure naming convention is not standardised throughout the world and is inconsistent with the PBN navigation specifications.
- From 1 December 2022, only the term RNP will be permitted, e.g. RNP RWY XX or RNP RWY XX (AR) will be acceptable while RNAV, GPS and GNSS will not be.
3
Q
CVR
A
- A device used to record the audio environment in the flight deck for accidents and incident investigation purposes.
- Fixed-wing aeroplanes with a maximum take-off mass of more than 5 700 kg and for which the certificate of airworthiness is first issued after 1 January 2003 shall be equipped with a CVR with a recording duration of two hours.
4
Q
RVSM equipment
A
- An operator shall ensure that aeroplanes operated in RVSM airspace are equipped with:
- Two independent altitude measurement systems;
- An altitude alerting system;
- An automatic altitude control system; and
- A secondary surveillance radar (SSR) transponder with altitude reporting system that can be connected to the altitude measurement system in use for altitude keeping.
5
Q
MSA
A
- The Minimum Sector Altitude (MSA) is the lowest altitude which may be used which will provide a minimum clearance of (1 000 ft) above all objects located in the area contained within a sector of a circle of (25 NM) radius centred on a radio aid to navigation.
6
Q
RVSM contingency
A
- Contingency procedures when unable to maintain RVSM
- The pilots shall notify ATC of any equipment failure, weather hazards such as severe turbulence etc., which may affect the ability to maintain the cleared level or the RVSM requirements. When an aircraft operating in RVSM Airspace encounters severe turbulence due to weather or wake vortex which the pilot believes will impact the aircraft’s capability to maintain its cleared flight level, the pilot shall inform ATC. ATC is required to establish either an appropriate horizontal separation minimum, or an increased vertical separation minimum of 2000ft;
- Where a meteorological forecast is predicting severe turbulence within the RVSM Airspace, ATC shall determine whether RVSM should be suspended, and, if so, the period of time, and specific flight level(s) and/or area.
- When notified by ATC of an assigned altitude deviation of more than 300ft (90 m), the pilot shall take action to return to the cleared level as quickly as possible.
- In the event of a pilot advising that the aircraft is no longer capable of RVSM operations, it is particularly important that the first ATS unit made aware of the failure performs the necessary co-ordination with subsequent ATS units.
7
Q
RVSM
A
- A program was initiated by ICAO in 1982 involving worldwide studies to assess the feasibility of a reduction of the Vertical Separation Minima (VSM) above FL290 from 2,000 feet to 1,000 feet.
- The principal benefits which the implementation of the reduced VSM were expected to provide were:
- A theoretical doubling of the airspace capacity, between FL290 and FL410; and
- The opportunity for aircraft to operate at closer to the optimum flight levels with the resulting fuel economies.
- An operator shall ensure that aeroplanes operated in RVSM airspace are equipped with:
- Two independent altitude measurement systems;
- An altitude alerting system;
- An automatic altitude control system; and
- A secondary surveillance radar (SSR) transponder with altitude reporting system that can be connected to the altitude measurement system in use for altitude keeping.
- Contingency procedures when unable to maintain RVSM
- The pilots shall notify ATC of any equipment failure, weather hazards such as severe turbulence etc., which may affect the ability to maintain the cleared level or the RVSM requirements. When an aircraft operating in RVSM Airspace encounters severe turbulence due to weather or wake vortex which the pilot believes will impact the aircraft’s capability to maintain its cleared flight level, the pilot shall inform ATC. ATC is required to establish either an appropriate horizontal separation minimum, or an increased vertical separation minimum of 2000ft;
- Where a meteorological forecast is predicting severe turbulence within the RVSM Airspace, ATC shall determine whether RVSM should be suspended, and, if so, the period of time, and specific flight level(s) and/or area.
- When notified by ATC of an assigned altitude deviation of more than 300ft (90 m), the pilot shall take action to return to the cleared level as quickly as possible.
- In the event of a pilot advising that the aircraft is no longer capable of RVSM operations, it is particularly important that the first ATS unit made aware of the failure performs the necessary co-ordination with subsequent ATS units.
- RVSM related phraseology
- Pilot reporting severe turbulence / weather affecting ability to maintain RVSM height keeping requirements - UNABLE RVSM DUE TURBULENCE
- Pilot reporting equipment degradation below RVSM requirements - UNABLE RVSM DUE EQUIPMENT
8
Q
ILS
A
- Instrument Landing System (ILS) is defined as a precision runway approach aid based on two radio beams which together provide pilots with both vertical and horizontal guidance during an approach to land.
- An Instrument Landing System is a precision runway approach aid employing two radio beams to provide pilots with vertical and horizontal guidance during the landing approach.
- The ILS LOC aerials are normally located at the end of the runway.
- The GS aerials are usually located so that the glide-slope provides a runway threshold crossing height of about 50 ft.
- Typically, the first marker beacon (the Outer Marker) would be located about 5 NM from touch-down while the second marker beacon (the Middle Marker) would be located about 1 NM from touch-down.
- Special categories of ILS approach are defined which allow suitably qualified pilots flying suitably equipped aircraft to suitably equipped runways using appropriately qualified ILS systems to continue an ILS approach without acquiring visual reference to a lower DH than the Category I standard of 200 feet above runway threshold elevation and do so when a lower reported RVR than the 550 metres usually associated with Category I:
- Category II permits a DH of not lower than 100 ft and an RVR not less than 300 m;
- Category IIIA permits a DH below 100 ft and an RVR not below 200 m;
- Category IIIB permits a DH below 50 ft and an RVR not less than 50 m;
- Category IIIC is a full auto-land with roll out guidance along the runway centreline and no DH or RVR limitations apply. This Category is not currently available routinely primarily because of problems which arise with ground manoeuvring after landing.
- The special conditions which apply for Category II and III ILS operation cover aircraft equipment; pilot training and the airfield installations. In the latter case, both function, reliability and operating procedures are involved. An example of the latter is the designation of runway holding points displaced further back from the runway so as to ensure that aircraft on the ground do not interfere with signal propagation. Reliability requirements for Category II and III ILS include a secondary electrical power supply which should be fully independent of the primary one.
9
Q
FANS
A
- The Future Air Navigation System (FANS) is an avionics system which provides direct data link communication between the pilot and the air traffic controller. The communications include air traffic control clearances, pilot requests and position reporting.[1] In the FANS-B equipped Airbus A320 family aircraft, an Air Traffic Services Unit (ATSU) and a VHF Data Link radio (VDR3) in the avionics rack and two data link control and display units (DCDUs) in the cockpit enable the flight crew to read and answer the controller–pilot data link communications (CPDLC) messages received from the ground.[2]
10
Q
ADS-B outputs?
A
- A means by which aircraft, aerodrome vehicles and other objects can automatically transmit and/or receive data such as identification, position and additional data, as appropriate, in a broadcast mode via a data link.
- ADS-B is a Surveillance technique that relies on aircraft or airport vehicles broadcasting their identity, position and other information derived from on board systems (GNSS etc.). This signal (ADS-B Out) can be captured for surveillance purposes on the ground (ADS-B Out) or on board other aircraft in order to facilitate airborne traffic situational awareness, spacing, separation and self-separation (ADS-B In)
- ADS-B is automatic because no external stimulus is required; it is dependent because it relies on on-board systems to provide surveillance information to other parties. Finally, the data is broadcast, the originating source has no knowledge of who receives the data and there is no interrogation or two-way contract.
- The introduction of ADS-B in the Surveillance infrastructure provides important features which can be exploited by the ATM Network:
- Full “Network-wide” Surveillance coverage
- Surveillance “everywhere”, i.e. no gaps from gate-to-gate
- Air-to-air Surveillance possible, i.e. traffic situational awareness picture available on board
- The aircraft is integral part of the Network
- Surveillance data provided directly from on-board systems
- High performance
- Improved safety
- Increased capacity
- Cost-efficiency
- Reduced cost of the Surveillance infrastructure (ADS-B is cheaper than radar)
- More efficient flight profiles (in areas where previously surveillance was not cost-effective)
- Fuel savings etc.
- Environmental sustainability (CO2 reduction)
- Reduced RF pollution (leading to an increased viability of the 1090 MHz datalink)
- Global Interoperability
- Foundation for future ATC applications (spacing, separation, self-separation)
- Full “Network-wide” Surveillance coverage
- The 1090 MHz Mode S Extended Squitter technology is used worldwide to ensure global interoperability. At local or regional level, other datalink technologies can be considered, e.g. the Universal Access Transceiver (UAT) system introduced in the USA.
- The “ADS-B Out” capability on board is enabled by transponders interfaced with the relevant avionics systems (such as GNSS, pressure altimeters etc.).
- The ADS-B data transmitted by the aircraft or airport vehicles are received by the ADS-B Ground stations.
- The ADS-B data transmitted are defined in the relevant standards and certification documents (e.g. EASA AMC 20-24 for ADS-B in Non-Radar Airspace or CS-ACNS for “ADS-B out”). They include (amongst others) the following:
- Aircraft horizontal position (latitude/longitude)
- Aircraft barometric altitude (will be the same as for the SSR)
- Quality indicators
- Aircraft identification:
- Unique 24-bit aircraft address
- Aircraft identification
- Mode A code (in the case of CS ACNS for “ADS-B Out”)
- Emergency status
- SPI (special position indicator) when selected
11
Q
CMV
A
RVR (Runway Visual Range) is considered to be better representation of expected distance that the pilot may acquire visual cues on approach than meteorological office reported horizontal visibility. Effect of lighting intensities and background luminescence play a role when establishing an RVR.
Due to commercial or other reasons RVR may not be available at all the airports and in such cases pilot may derive RVR/CMV-Converted Meteorological Visibility by using mathematical conversions depending upon the type of approach lighting and day/night conditions.
Following table is used to calculate CMV.
CMV
Note:
Conversion of meteorological visibility to RVR is not be used:
for takeoff,
for calculating any other requred RVR minimum less than 800 m,
for visual/circling approaches,
or when reported RVR is available
12
Q
TCAS
A
- ACAS II is an aircraft system based on Secondary Surveillance Radar (SSR) transponder signals. ACAS II interrogates the Mode C and Mode S transponders of nearby aircraft (‘intruders’) and from the replies tracks their altitude and range and issues alerts to the pilots, as appropriate. ACAS II will not detect non-transponder-equipped aircraft and will not issue any resolution advice for traffic without altitude reporting transponder.
- Currently, the only commercially available implementations of ICAO standard for ACAS II (Airborne Collision Avoidance System) is TCAS II version 7.1 (Traffic alert and Collision Avoidance System). ICAO Annex 10 vol. IV states that all ACAS II units must be complaint with version 7.1 as of 1 January 2017. In Europe version 7.1 has been mandatory since 1 December 2015.
- The maximum generation time for a TA is 48 seconds before the Closest Point of Approach (CPA). For an RA the time is 35 seconds. The time scales are shorter at lower altitudes (where aircraft typically fly slower).
- ACAS III Gives TAs and RAs in vertical and/or horizontal directions. Also referred to as TCAS III and TCAS IV. Not currently implemented and unlikely to be in the near future. ICAO SARPs for ACAS III have not been developed. Currently, there are no plans to proceed with such a development.
- ACAS X, a future collision avoidance system, is currently being developed.
13
Q
GC vs. RL
A
Great Circle: A circle on the surface of the earth whose centre and radius are
those of the earth itself. It is circle of the surface of the sphere whose centre and diameter are that of earth. A plane of the great circle divides the earth in two equal parts. Great circle distance is the shortest distance along the arc of the great circle however this is not constant.
Meridian and its anti-meridian make a great circle.
Rhumb Line: Rhumb line is a regularly curved line on the surface of the earth which cuts all the meridians on the earth at same angle. It is curve concaved to the nearer pole. Rhumb line track is constant between two positions but the distance is longer.
Equator and meridian are the only two examples on the surface of the earth which are great circles as well as rhumb line.
14
Q
IDL
A
The International Date Line (IDL) is an imaginary line of demarcation on the surface of Earth that runs from the North Pole to the South Pole and demarcates the boundary between one calendar day and the next. It passes through the middle of the Pacific Ocean, roughly following the 180° line of longitude but deviating to pass around some territories and island groups.
15
Q
why is RVSM not available above FL410?
A
For flights above FL410, 2000 feet of separation is used. Which makes all flight levels odd numbered, →410, ←430, →450, ←470, →490, ←510, …
So for each direction as indicated above by arrows, it’ll be 4000 feet.
The 2000 feet separation is because the higher up you go the less accurate an altimeter becomes, so it’s for safe separation.
