SACATS Part 91 IR | ACAS, GPS, RCF, Dest Alt

Question 1

ACAS is an acronym for -

The US equivalent for ACAS -

The latter consist of two versions, what is the difference?

ACAS 2 also provides -

Answer 1

Airborne Collision Avoidance System

TCAS(Traffic Collision avoidance system)

TCAS 1 and TCAS 2. TCAS 1 provides only traffic alert messages where TCAS 2 provides both Resolution Advisory messages and traffic messages

Advisory messages if the intruder is ACAS 2 or transponder mode C equipped.

Question 2

(1)
GPS systems normally provide three modes of operation –

(a)
navigation (nav) solution with RAIM;

(b)
2D or 3D nav solution without RAIM; and

(c)
dead reckoning (DR), or loss of nav solution.

(2)
ATS services, and in particular ATC separation standards, are dependent on accurate navigation and position fixing. If ____ is lost, the accuracy of the system is assumed not to meet the required standard for both navigation and application of ATC separation. Accordingly, when RAIM is lost, the following procedures must be adopted –

(a)
aircraft tracking must be closely monitored against other on-board systems;

(b)
in controlled airspace, the ATS unit must be advised if –
(i)
RAIM is lost for periods greater than __ minutes, even if GPS is still providing positional information;
(ii)
RAIM is not available when the ATS unit requests GPS distance or if an ATC clearance or requirement based on GPS distance is imposed;
(iii)
the GPS receiver is in __ mode or experiences loss of navigation function for more than __ minute; or
(iv)
indicated displacement from track centreline is found to exceed _ NM; and ATS may then adjust separation;

(c)
if valid position information is lost (2D and DR Mode) or non-RAIM operation exceeds __ minutes, the GPS information is to be considered unreliable and another means of _________ should be used until RAIM is restored and the aircraft is re-established on track;

(d)
following re-establishment of RAIM, the appropriate ATS unit should be _____ of RAIM restoration, prior to using GPS information. This will allow the ATS unit to reassess the appropriate separation standards; and

(e)
when advising the ATS unit of the status of GPS the phrases“RAIM FAILURE” or “RAIM RESTORED” must be used.

Answer 2

(1)
GPS systems normally provide three modes of operation –

(a)
navigation (nav) solution with RAIM;

(b)
2D or 3D nav solution without RAIM; and

(c)
dead reckoning (DR), or loss of nav solution.

(2)
ATS services, and in particular ATC separation standards, are dependent on accurate navigation and position fixing. If RAIM is lost, the accuracy of the system is assumed not to meet the required standard for both navigation and application of ATC separation. Accordingly, when RAIM is lost, the following procedures must be adopted –

(a)
aircraft tracking must be closely monitored against other on-board systems;

(b)
in controlled airspace, the ATS unit must be advised if –
(i)
RAIM is lost for periods greater than ten minutes, even if GPS is still providing positional information;
(ii)
RAIM is not available when the ATS unit requests GPS distance or if an ATC clearance or requirement based on GPS distance is imposed;
(iii)
the GPS receiver is in DR mode or experiences loss of navigation function for more than one minute; or
(iv)
indicated displacement from track centreline is found to exceed 2 NM; and ATS may then adjust separation;

(c)
if valid position information is lost (2D and DR Mode) or non-RAIM operation exceeds ten minutes, the GPS information is to be considered unreliable and another means of navigation should be used until RAIM is restored and the aircraft is re-established on track;

(d)
following re-establishment of RAIM, the appropriate ATS unit should be notified of RAIM restoration, prior to using GPS information. This will allow the ATS unit to reassess the appropriate separation standards; and

(e)
when advising the ATS unit of the status of GPS the phrases “RAIM FAILURE” or “RAI

Question 3

GPS distance information to air traffic service units

(1)
When a DME distance is requested by an ATS unit, DME-derived distance information should normally be provided. Alternatively, GPS-derived distance information may be provided to an ATS unit, unless ____ is currently ________ and has been unavailable for the preceding __ minutes.

(2)
Notwithstanding paragraph (1), if an ATS unit has issued a clearance or requirement based upon GPS distance (e.g. a requirement to reach a certain level by a GPS distance), pilots must inform the ATS unit if \_\_\_\_ is not \_\_\_\_\_\_\_.

(3)
When a DME distance is not specifically requested or when the provision of a DME distance is not possible, distance information based on GPS-derived information may be provided. When providing ___ distance, transmission of distance information must include the _____ and point of ________ – e.g. 115 NM GPS JSV, 80 NM GPS VAL NDB, 267 NM GPS ORNAD, etc.

(4)
If a GPS distance is provided to an ATS unit and RAIM is not currently available, but has been available in the preceding __ minutes, the distance report should be suffixed “________ ____” – e.g. 26 NM GPS BLV NEGATIVE RAIM.

(5)
Databases sometimes contain waypoint information which is not shown on published AIP charts and maps. Distance information must only be provided in relation to published waypoints unless specifically requested by an ATS unit.

(6)
Where GPS distance is requested or provided from an NDB, VOR, DME or published waypoint, the latitude and longitude of the navigation air or waypoint must be derived from a validated database which cannot be modified by the operator or flight crew.

Answer 3

GPS distance information to air traffic service units

(1)
When a DME distance is requested by an ATS unit, DME-derived distance information should normally be provided. Alternatively, GPS-derived distance information may be provided to an ATS unit, unless RAIM is currently unavailable and has been unavailable for the preceding ten minutes.

(2)
Notwithstanding paragraph (1), if an ATS unit has issued a clearance or requirement based upon GPS distance (e.g. a requirement to reach a certain level by a GPS distance), pilots must inform the ATS unit if RAIM is not available.

(3)
When a DME distance is not specifically requested or when the provision of a DME distance is not possible, distance information based on GPS-derived information may be provided. When providing GPS distance, transmission of distance information must include the source and point of reference – e.g. 115 NM GPS JSV, 80 NM GPS VAL NDB, 267 NM GPS ORNAD, etc.

(4)
If a GPS distance is provided to an ATS unit and RAIM is not currently available, but has been available in the preceding 10 minutes, the distance report should be suffixed “NEGATIVE RAIM” – e.g. 26 NM GPS BLV NEGATIVE RAIM.

(5)
Databases sometimes contain waypoint information which is not shown on published AIP charts and maps. Distance information must only be provided in relation to published waypoints unless specifically requested by an ATS unit.

(6)
Where GPS distance is requested or provided from an NDB, VOR, DME or published waypoint, the latitude and longitude of the navigation air or waypoint must be derived from a validated database which cannot be modified by the operator or flight crew.

Question 4

Data integrity

(1)
As a significant number of data errors, in general applications, occur as a result of manual data entry errors, navigation aid and waypoint latitude and longitude data should be derived from a database, if available, which cannot be modified by the operator or flight crew.

(2)
It is the responsibility of the owner or operator to ensure the GPS database is current and accurate. The GPS database shall be updated with data provided by the manufacturer or other approved source, hereinafter referred to as the “provider”. The frequency of database updating shall be as the provider determines but, in any event, an owner or operator shall, within _ months of the date the latest issue was received, confirm with the provider that such update is the most recent.

(3)
When data is entered manually, data entries must be ____-checked by at least two flight crew members for accuracy and reasonableness, or, for single pilot operations, an independent check (e.g. GPS computed tracks and distances against current chart data) must be made.

(4)
Both manually entered and database-derived position and tracking information should be checked for reasonableness (confidence check) in the following cases –

(a)
prior to each __________ reporting point;

(b)
at or prior to arrival at each en route waypoint;

(c)
at hourly intervals during area type operations when operating off established routes; and

(d)
after insertion of new data (e.g. creation of new flight plan).

Answer 4

Data integrity

(1)
As a significant number of data errors, in general applications, occur as a result of manual data entry errors, navigation aid and waypoint latitude and longitude data should be derived from a database, if available, which cannot be modified by the operator or flight crew.

(2)
It is the responsibility of the owner or operator to ensure the GPS database is current and accurate. The GPS database shall be updated with data provided by the manufacturer or other approved source, hereinafter referred to as the “provider”. The frequency of database updating shall be as the provider determines but, in any event, an owner or operator shall, within 2 months of the date the latest issue was received, confirm with the provider that such update is the most recent.

(3)
When data is entered manually, data entries must be cross-checked by at least two flight crew members for accuracy and reasonableness, or, for single pilot operations, an independent check (e.g. GPS computed tracks and distances against current chart data) must be made.

(4)
Both manually entered and database-derived position and tracking information should be checked for reasonableness (confidence check) in the following cases –

(a)
prior to each compulsory reporting point;

(b)
at or prior to arrival at each en route waypoint;

(c)
at hourly intervals during area type operations when operating off established routes; and

(d)
after insertion of new data (e.g. creation of new flight plan).

Question 4

Radio communication failure (RCF) procedures – General

(1)
When an aircraft fails to establish contact with the aeronautical station on the designated frequency, it shall attempt to establish ______ on another ________ appropriate to the ____. If this attempt ____, the aircraft shall attempt to establish communication with other _____ or other aeronautical ______ on frequencies appropriate to the _____. In addition, an aircraft shall ______ the appropriate VHF frequency for calls from nearby aircraft or aeronautical stations.

(2)
If these attempts fail, the aircraft station shall _______ to transmit _______ reports and its _______ as appropriate on the designated frequency or frequencies, ________ by the phrase “_________ ____”. Such messages shall be transmitted _____ and, if necessary, include the addressee(s) for which the message is intended.

(3)
If no communication is received or other indication that one-way communications are possible, the aircraft shall set its transponder to Code ______ and proceed with the lost communications procedures.

(4)
In any case, whereby an aircraft having suffered a communication failure in flight arrives at an aerodrome, it shall keep a watch for such instructions as may be issued by visual signals from the aerodrome control tower or other facility.

Answer 4

Radio communication failure (RCF) procedures – General

(1)
When an aircraft fails to establish contact with the aeronautical station on the designated frequency, it shall attempt to establish contact on another frequency appropriate to the route. If this attempt fails, the aircraft shall attempt to establish communication with other aircraft or other aeronautical stations on frequencies appropriate to the route. In addition, an aircraft shall monitor the appropriate VHF frequency for calls from nearby aircraft or aeronautical stations.

(2)
If these attempts fail, the aircraft station shall continue to transmit position reports and its intentions as appropriate on the designated frequency or frequencies, preceded by the phrase “Transmitting Blind”. Such messages shall be transmitted twice and, if necessary, include the addressee(s) for which the message is intended.

(3)
If no communication is received or other indication that one-way communications are possible, the aircraft shall set its transponder to Code 7600 and proceed with the lost communications procedures.

(4)
In any case, whereby an aircraft having suffered a communication failure in flight arrives at an aerodrome, it shall keep a watch for such instructions as may be issued by visual signals from the aerodrome control tower or other facility.

Question 5

(1)
If the communications failure occurs while operating in accordance with IFR and VMC are encountered, the aircraft shall –

(a)
continue to fly in ___; land at the ______ suitable aerodrome in accordance with –
(i)
the standard RCF arrival procedures prescribed in Appendix 1 to this TS; or
(ii)
if other procedures have been published by the Director for a specific aerodrome, in accordance with such procedures; and

(b)
report its arrival by the most expeditious means to the appropriate ATSU; or

(c)
if unable to ensure ___ conditions exist to a suitable aerodrome, complete an __ flight in accordance with paragraph (2).

(2)
If the communications failure occurs while operating in accordance with IFR while in IMC or, if in VMC but unable to maintain VMC, the aircraft shall –

(a)
in airspace where an ATS surveillance system is not used in the provision of air traffic control, maintain the last assigned ____ and ____, or minimum flight altitude if ____, for a period of __ minutes following the aircraft’s failure to report its position over a _________ reporting point and thereafter adjust level and speed in accordance with the filed ____ ___;

(b)
in airspace where an ATS surveillance system is used in the provision of air traffic control, maintain the last assigned _____ and ____, or minimum flight altitude if higher, for a period of _ minutes following –
(i)
the time the last assigned level or minimum flight altitude was _____;
(ii)
the time the transponder was set to Code _____; or
(iii)
the aircraft’s failure to report its ______ over a _________ reporting point;
whichever is ____, and thereafter adjust level and speed in accordance with the filed ____ ___;

(c)
when being radar vectored or having been directed by ATC to proceed offset using area navigation (RNAV) without a specified limit, ______ the current flight plan route no later than the next ________ ____, taking into consideration the applicable minimum flight altitude;

(d)
proceed according to the current ____ ___ ____ to the appropriate designated navigation aid or fix serving the _________ _______ and, when required to ensure compliance with sub-paragraph (e), ____ over this aid or fix until commencement of descent;

(e)
commence descent from the navigation aid or fix specified in sub-paragraph (d) at, or as close as possible to, the ________ _______ ____ last received and acknowledged or, if no expected approach time has been received and acknowledged, at, or as close as possible to, the _______ ___ of ____ resulting from the current flight plan;

(f)
complete a normal instrument approach procedure as specified for the designated navigation aid or fix; and

(g)
land, if possible, within __ minutes after the estimated time of arrival specified in (e) or the last acknowledged expected approach time, whichever is ____.

Answer 5

(1)
If the communications failure occurs while operating in accordance with IFR and VMC are encountered, the aircraft shall –

(a)
continue to fly in VMC; land at the nearest suitable aerodrome in accordance with –
(i)
the standard RCF arrival procedures prescribed in Appendix 1 to this TS; or
(ii)
if other procedures have been published by the Director for a specific aerodrome, in accordance with such procedures; and

(b)
report its arrival by the most expeditious means to the appropriate ATSU; or

(c)
if unable to ensure VMC conditions exist to a suitable aerodrome, complete an IFR flight in accordance with paragraph (2).

(2)
If the communications failure occurs while operating in accordance with IFR while in IMC or, if in VMC but unable to maintain VMC, the aircraft shall –

(a)
in airspace where an ATS surveillance system is not used in the provision of air traffic control, maintain the last assigned speed and level, or minimum flight altitude if higher, for a period of 20 minutes following the aircraft’s failure to report its position over a compulsory reporting point and thereafter adjust level and speed in accordance with the filed flight plan;

(b)
in airspace where an ATS surveillance system is used in the provision of air traffic control, maintain the last assigned speed and level, or minimum flight altitude if higher, for a period of 7 minutes following –
(i)
the time the last assigned level or minimum flight altitude was reached;
(ii)
the time the transponder was set to Code 7600; or
(iii)
the aircraft’s failure to report its position over a compulsory reporting point;
whichever is later, and thereafter adjust level and speed in accordance with the filed flight plan;

(c)
when being radar vectored or having been directed by ATC to proceed offset using area navigation (RNAV) without a specified limit, rejoin the current flight plan route no later than the next significant point, taking into consideration the applicable minimum flight altitude;

(d)
proceed according to the current flight plan route to the appropriate designated navigation aid or fix serving the destination aerodrome and, when required to ensure compliance with sub-paragraph (e), hold over this aid or fix until commencement of descent;

(e)
commence descent from the navigation aid or fix specified in sub-paragraph (d) at, or as close as possible to, the expected approach time last received and acknowledged or, if no expected approach time has been received and acknowledged, at, or as close as possible to, the estimated time of arrival resulting from the current flight plan;

(f)
complete a normal instrument approach procedure as specified for the designated navigation aid or fix; and

(g)
land, if possible, within 30 minutes after the estimated time of arrival specified in (e) or the last acknowledged expected approach time, whichever is later.

Question 6

Minimum flight altitude formula:

Minimum off-route altitude (MORA) is a minimum flight altitude computed from current ONC or WAC charts. An operator must use the following method to calculate minimum flight altitudes –

(a)
two types of MORAs are charted which are –
(i)
\_\_\_\_ MORAs e.g. 9800a; and
(ii)
\_\_\_ MORAs e.g. 98;

(b)
route MORA values are computed on the basis of an area extending __ NM to either side of route centreline and including a __ NM radius beyond the radio fix/reporting point or mileage break defining the route segment;

(c)
MORA values clear all terrain and man-made obstacles by _____ feet in areas where the highest terrain elevation or obstacles are up to ______ feet. A clearance of _____ feet is provided above all terrain or obstacles which are _____ feet and above; and

(d)
a grid MORA is an altitude computed by the formula and the values are shown within each grid formed by charted lines of latitude and longitude. Figures are shown in thousands and hundreds of feet (omitting the last two digits so as to avoid chart congestion). Values followed by ± are believed not to exceed the altitudes shown. The same clearance criteria as explained in sub-paragraph (c) above apply.

Answer 6

Minimum flight altitude formula
Minimum off-route altitude (MORA) is a minimum flight altitude computed from current ONC or WAC charts. An operator must use the following method to calculate minimum flight altitudes –

(a)
two types of MORAs are charted which are –
(i)
route MORAs e.g. 9800a; and
(ii)
grid MORAs e.g. 98;

(b)
route MORA values are computed on the basis of an area extending 10 NM to either side of route centreline and including a 10 NM radius beyond the radio fix/reporting point or mileage break defining the route segment;

(c)
MORA values clear all terrain and man-made obstacles by 1 000 feet in areas where the highest terrain elevation or obstacles are up to 5 000 feet. A clearance of 2 000 feet is provided above all terrain or obstacles which are 5 001 feet and above; and

(d)
a grid MORA is an altitude computed by the formula and the values are shown within each grid formed by charted lines of latitude and longitude. Figures are shown in thousands and hundreds of feet (omitting the last two digits so as to avoid chart congestion). Values followed by ± are believed not to exceed the altitudes shown. The same clearance criteria as explained in sub-paragraph (c) above apply.

Question 7

An owner or operator may only select the destination aerodrome or alternate destination aerodrome, if required, when the appropriate weather reports or forecasts, or any combination thereof, indicate that, during a period commencing _ hour before and ending _ hour after the __ at the aerodrome, the weather conditions will be __ or ____ the applicable planning minima as follows –

(a)
planning minima for the destination aerodrome –
(i)
RVR/visibility must be in accordance with that specified in CAR 91.07.5; and
(ii)
for a non-precision approach or a circling approach, the ceiling at or above ___; and

(b)
planning minima for destination ________ aerodrome must be in accordance with Table 1.

Answer 7

An owner or operator may only select the destination aerodrome or alternate destination aerodrome, if required, when the appropriate weather reports or forecasts, or any combination thereof, indicate that, during a period commencing 1 hour before and ending 1 hour after the estimated time of arrival at the aerodrome, the weather conditions will be at or above the applicable planning minima as follows –

(a)
planning minima for the destination aerodrome –
(i)
RVR/visibility must be in accordance with that specified in CAR 91.07.5; and
(ii)
for a non-precision approach or a circling approach, the ceiling at or above MDH; and

(b)
planning minima for destination alternate aerodrome must be in accordance with Table 1.

Question 8

Planning criteria for aeroplanes:

Except as provided in Part 91, 93, Part 121 and Part 135, an owner or operator must base the fuel policy, including calculation of the amount of fuel and oil to be carried by an aeroplane, on the following planning criteria –

(1)
when the flight is conducted in accordance with the instrument flight rules and a destination alternate aerodrome is not required in accordance with regulation 91.07.7(6), flight to the aerodrome of intended landing and thereafter for at least __ minutes at the normal cruising altitude consumption rate;

(2)
when the flight is conducted in accordance with the instrument flight rules and a destination alternate aerodrome is required, flight to the aerodrome of intended landing, thence from the aerodrome of intended landing to an alternate aerodrome and thereafter for at least __ minutes at the normal cruising altitude consumption rate;

(3)
when the flight is conducted in accordance with the visual flight rules by day, flight to the aerodrome of intended landing and thereafter for at least __ minutes at the normal cruising altitude consumption rate; or

(4)
When the flight is conducted in accordance with the visual flight rules by night, flight to the aerodrome of intended landing and thereafter for at least __ minutes at the normal cruising altitude consumption rate.

Answer 8

Planning criteria for aeroplanes
Except as provided in Part 91, 93, Part 121 and Part 135, an owner or operator must base the fuel policy, including calculation of the amount of fuel and oil to be carried by an aeroplane, on the following planning criteria –

(1)
when the flight is conducted in accordance with the instrument flight rules and a destination alternate aerodrome is not required in accordance with regulation 91.07.7(6), flight to the aerodrome of intended landing and thereafter for at least 45 minutes at the normal cruising altitude consumption rate;

(2)
when the flight is conducted in accordance with the instrument flight rules and a destination alternate aerodrome is required, flight to the aerodrome of intended landing, thence from the aerodrome of intended landing to an alternate aerodrome and thereafter for at least 45 minutes at the normal cruising altitude consumption rate;

(3)
when the flight is conducted in accordance with the visual flight rules by day, flight to the aerodrome of intended landing and thereafter for at least 30 minutes at the normal cruising altitude consumption rate; or

(4)
When the flight is conducted in accordance with the visual flight rules by night, flight to the aerodrome of intended landing and thereafter for at least 45 minutes at the normal cruising altitude consumption rate.