.TAWS and ACAS (TCAS)
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TAWS and ACAS (TCAS)
At one point transport was moving in the direction of requiring turbine aircraft having both TAWS and TCAS at the same implementaion date as in the US. I know they have pushed this back, but does anyone know where to find the info. I haven't been able to find it on the wonderfully user friendly TC site .
.-
Frank Castle
- Rank 2
- Posts: 50
- Joined: Sat Mar 20, 2004 1:53 pm
- Location: Rikers Island
Here is the circular, thanks Bezerker. As far as I know both are now mandatory in the US as of early 2005.
Class B TAWS for turbine aircraft with 6-9 pax seats, class A for 10+ seats and for aircraft doing other work based on weights.
COMMERCIAL AND BUSINESS
AVIATION ADVISORY CIRCULAR No. 0236
2005.07.29
--------------------------------------------------------------------------------
Regulations for Terrain Awareness Warning System and Airborne Collision Avoidance System
INTRODUCTION
This Commercial and Business Aviation Circular (CBAAC) is intended to inform Air Operators that are considering the implementation of a Terrain Awareness Warning System (TAWS) and an Airborne Collision Avoidance System (ACAS), what is the current status and implementation dates of applicable regulations.
APPLICABILITY
Transport Canada (TC) has developed regulations that will require the installation and operation of TAWS for Commercial Air Taxi, Commuter and Airline Operations (Subparts 703, 704 and 705 of the Canadian Aviation Regulations (CARs)) and Private Air Operators (Subpart 604 of the CARs) to prevent Controlled Flight Into Terrain (CFIT) accidents. TC has also developed regulations that will require installation and operation of ACAS for commercial Aerial Work, Air Taxi, Commuter and Airline Operations (Subparts 702, 703, 704 and 705 of the CARs).
REFERENCES
Airworthiness Manual (AWM), Chapter 537, Airworthiness Standards, Appliances, Subchapter B, Technical Standard Orders (TSOs) 537.103 contains a list of adopted United States TSOs in Canada. This may be referenced by internet at:
http://www.tc.gc.ca/civilaviation/regse ... 5/menu.htm
Procurement of Reference Publications
TSOs referenced in this CBAAC may be purchased from:
Superintendent of Documents
U.S. Government Printing Office
Washington D.C. 20402
And by internet at: http://www.faa.gov/avr/air/air100/tsocur/Current.htm or at: http://av-info.faa.gov/redirects/tso.htm
AWM Chapter 551, Aircraft Equipment and Installation, may be referenced at:
http://www.tc.gc.ca/civilaviation/Regse ... Standards/
Chapter551.htm
TERMINOLGY
TAWS
TAWS - Terrain Awareness Warning System
GPWS - Ground Proximity Warning System
Mode 1: Excessive Descent Rate
Mode 2: Excessive Terrain Closure Rate
Mode 3: Altitude Loss After Takeoff
Mode 4: Flight Into Terrain
Mode 5: Excessive Deviation Below Glideslope
Mode 6: Advisory Call-outs, Bank Angle and Altitude (not regulated, but certified for intended function)
Mode 7: Windshear (Federal Aviation Administration (FAA) regulated, aircraft certified for intended function)
FLTA - Forward Looking Terrain Avoidance (TAWS look ahead function)
PDA - Premature Descent Alert (TAWS alert if aircraft is hazardously below the normal approach path for the nearest runway)
Class A TAWS = GPWS (Modes 1 to 5 only) + FLTA + PDA (formerly Honeywell trade name EGPWS, Enhanced GPWS)
Class B TAWS = Modes 1 and 3 only + FLTA + PDA
ACAS
ACAS - Airborne Collision Avoidance System
TCAS - Traffic Alert and Collision Avoidance System
Note: The acronym ACAS can be used interchangeably with TCAS. ACAS is International Civil Aviation Organization (ICAO) terminology, TCAS is FAA terminology. ACAS is going to be used predominantly throughout this advisory circular because the proposed Canadian regulations use the acronym ACAS.
TA - Traffic Advisory - aural and visual alerts and information on position of other aircraft in immediate vicinity
RA - Resolution Advisory - aural and visual alerts and information to avoid a potential airborne collision
TCAS I - TCAS providing TA only
TCAS II - TCAS providing TA and RA
(TCAS II has two prevailing software standards, namely Software (SW) version 6.04a and 7.0. TCAS II with SW version 7.0 is also referred to as ACAS II.)
BACKGROUND
TAWS
TAWS equipment provides aural and visual alerts (both cautions and warnings) to flight crew when the path of the aircraft is predicted to collide with terrain (in some systems, also with obstacles), and this allows flight crews sufficient time to take action. CFIT is an accident or incident in which the airplane, under the flight crew’s control, is inadvertently flown into terrain, obstacles, or water without either sufficient or timely flightcrew awareness to prevent the event.
CFIT is a leading cause of fatalities in airline accidents worldwide since the collision with terrain usually results in total destruction of the aircraft. CFIT is a significant hazard in mountainous terrain, such as that found in many regions of Canada, where a navigational error can have a disastrous outcome. Some airline operators have begun to voluntarily install TAWS equipment because of its demonstrated safety benefits, and its effect on insurance premiums.
TAWS equipment provides a significant improvement over older technology GPWS, and has been proven to alert flight crew to hazardous situations. ICAO has issued standards to require the installation of TAWS equipment on most aircraft in commercial and general aviation operations. The United States FAA also has comprehensive regulations requiring TAWS equipment for commercial and non-commercial operations.
The proposed TC regulations for TAWS were developed in recognition of the safety benefits of TAWS equipment, and to harmonize with regulations in place with organizations noted above, namely, the ICAO and FAA, as well as the Mexican Dirección General de Aeronáutica Civil. Furthermore, the TC regulations were developed in response to a Transportation Safety Board (TSB) recommendation for the installation of TAWS equipment. The new regulations for TAWS will supersede the regulatory requirement for GPWS under the current Subpart 605 of the CARs regulations (Section 605.37).
ACAS
ACAS equipment alerts flight crews when the path of the aircraft is predicted to collide with that of another aircraft and includes aural and visual alerts and cockpit displays of other traffic. The two major classes of ACAS equipment are TCAS I and TCAS II. TCAS I provides a display of other traffic and aural and visual alerts only. TCAS II, in addition to the capabilities of TCAS I, provides guidance to flight crews to avoid collision with other transponder equipped aircraft.
The proposed TC regulations for ACAS were developed in recognition of the safety benefits of the equipment, and with the goal of having similar regulations in place as ICAO and the FAA. Furthermore TC regulations were developed as an outcome of a TSB recommendation for TC to analyze the benefits of ACAS for commercial passenger carrying aircraft.
POLICY DEVELOPMENT
TAWS
New NPAs containing regulations and standards were accepted for TAWS for aeroplanes operating under Subparts 703, 704 and 705 of the CARs. New NPAs were also accepted under Subpart 605 of the CARs for Aircraft Equipment Requirements, which will compel certain aeroplanes operating under Subpart 604 of the CARs to be equipped with TAWS. These NPAs were intended to supercede a previous NPA that was under regulatory review. The new NPAs address additional technical issues and allow relief in the regulations for certain types of operations (e.g. VFR only operations) not considered in the original NPA.
The proposed TC regulations and standards will require one of two classes of TAWS equipment, depending on the aeroplane seating configuration and type of operation. This is in consideration of the safety benefits of the class of TAWS equipment to prevent CFIT accidents, balanced against the cost of this equipment. The regulations and standards include a provision that the TAWS equipment provides adequate warning in common Canadian operating conditions of low temperatures and barometric pressures. They also have provisions to relieve operators from equipping with TAWS, if they operate exclusively in day Visual Flight Rules (VFR) conditions (Subpart 703, 704 and Subpart 605 of the CARs).
Class B TAWS meeting design requirements of FAA TSO C-151, or later versions, will be the minimum acceptable standard of TAWS equipment for Subpart 703 of the CARs, aeroplanes used in Air Taxi Operations configured with 6 or more passenger seats (excluding any pilot seat) and Subpart 704 of the CARs, aeroplanes used in Commuter Operations with 6 to 9 passenger seats. Class B TAWS will also be the minimum standard of TAWS under the Subpart 605 of the CARs regulation for turbine-powered aeroplanes configured with 6 or more passenger seats. (This will compel affected aeroplanes operating under Subpart 604 of the CARs to be equipped accordingly). Class A TAWS per the TSO, will also be satisfactory for these aeroplanes.
Class A TAWS meeting design requirements of FAA TSO C-151, or later versions, and a Terrain Awareness Display, will be required for Subpart 704 of the CARs, aeroplanes used in Commuter Operations configured with 10 or more passenger seats and for all Subpart 705 of the CARs, aeroplanes used in Airline Operations.
All TAWS equipment installations will be in accordance with applicable Canadian airworthiness requirements contained in Chapter 551 of the AWM, including additional approved (non-barometric) altitude inputs, to ensure that TAWS has the required vertical accuracy. This will ensure that TAWS functions correctly in the Canadian operating environment, during non-standard cold atmospheric temperature conditions, and when operating in standard pressure regions. All operators will also be required to ensure that the TAWS equipment terrain and airport database are compatible with the area of operations.
TAWS will not be required for aeroplanes conducting day VFR operations under Subparts 703 and 704 of the CARs as well as under Subpart 605 of the CARs regulation. This is because of incompatibilities between the TAWS alerting envelopes and the minimum altitudes permitted by the regulations for en-route obstacle clearance.
Table 1 (Annex A) summarizes all of the above information on TAWS.
ACAS
New NPAs containing regulations were submitted for ACAS equipment for aeroplanes operating under Subparts 702, 703, 704 and 705 of the CARs. These NPAs were intended to supercede a previous NPA that was under regulatory review.
The earlier regulatory proposal for ACAS was in harmony with the criteria in upcoming ICAO Standards and Recommend Practices (SARPs). The new NPAs are intended to be more in harmony with existing and proposed FAA regulations for TCAS. The high cost of the ACAS equipment on the Aerial Work, Air Taxi and Commuter operations was also reviewed. The new regulations provide revised criteria for suitable ACAS equipment matched to the aeroplane weight, power plant and operation that balance the safety benefits with the cost of the installation.
TCAS I will be the minimum acceptable collision avoidance system for large aeroplanes (Maximum Certificated Take-off Weight (MCTOW) greater than 12,500 lbs/5,700 kgs) operating under Subpart 703 of the CARs, Air Taxi and Subpart 704 of the CARs, Commuter operations.
TCAS II (SW version 6.04a) and a mode S transponder, will be the minimum acceptable collision avoidance system for turbine-powered aeroplanes operating under Subpart 705 of the CARs, Airline operations, and for turbine-powered aeroplanes with a MCTOW exceeding 33,000 lbs/15,000 kgs operating under Subpart 702 of the CARs (turbine powered land aeroplanes only) and Subpart 704 of the CARs.
TCAS II (ACAS II SW version 7.0) and a mode S transponder will be the minimum acceptable collision avoidance system for all aeroplanes, operating under Subparts 702, 703, 704 and 705 of the CARs requiring ACAS equipment by the new regulations, when operations are conducted in Reduced Vertical Separation Minima (RVSM) airspace.
Table 2 (Annex B) summarizes all of the above information on ACAS.
ACTION
IMPLEMENTATION DATES
TAWS
The new TAWS regulations will be effective for newly manufactured aeroplanes on the date the regulations are promulgated. This also applies to newly manufactured aircraft that enter Canada on a lease back arrangement. All aeroplanes will have to be in compliance two years after the date the regulations are promulgated. For the purposes of future planning, the Minister will contemplate delaying the implementation to not earlier than September 30, 2008. All aeroplanes will have to be in compliance with the TAWS altitude accuracy requirements 5 years after the date the regulations are promulgated. Again, for the purposes of future planning, the Minister will contemplate delaying the implementation to not earlier than September 30, 2010.
Section 605.37 of the CARs is being amended to no longer require GPWS equipment for all aeroplanes, to coincide with the date all aeroplanes will have to be equipped with TAWS by the new regulations.
ACAS
The new ACAS regulations will be effective for newly manufactured aeroplanes on the date the regulations are promulgated. All aeroplanes will have to be in compliance two years after the date the regulations are promulgated.
FUTURE DISPOSITION
TC is committed to maintaining a viable civil aviation transportation system, while not compromising safety. This CBAAC will remain in effect for information purposes until further notice.
CONCLUSION
This CBAAC brings to the attention of air operators the current status and implementation dates of applicable regulations of TAWS and ACAS.
Michel Gaudreau
Director
Commercial and Business Aviation
Class B TAWS for turbine aircraft with 6-9 pax seats, class A for 10+ seats and for aircraft doing other work based on weights.
COMMERCIAL AND BUSINESS
AVIATION ADVISORY CIRCULAR No. 0236
2005.07.29
--------------------------------------------------------------------------------
Regulations for Terrain Awareness Warning System and Airborne Collision Avoidance System
INTRODUCTION
This Commercial and Business Aviation Circular (CBAAC) is intended to inform Air Operators that are considering the implementation of a Terrain Awareness Warning System (TAWS) and an Airborne Collision Avoidance System (ACAS), what is the current status and implementation dates of applicable regulations.
APPLICABILITY
Transport Canada (TC) has developed regulations that will require the installation and operation of TAWS for Commercial Air Taxi, Commuter and Airline Operations (Subparts 703, 704 and 705 of the Canadian Aviation Regulations (CARs)) and Private Air Operators (Subpart 604 of the CARs) to prevent Controlled Flight Into Terrain (CFIT) accidents. TC has also developed regulations that will require installation and operation of ACAS for commercial Aerial Work, Air Taxi, Commuter and Airline Operations (Subparts 702, 703, 704 and 705 of the CARs).
REFERENCES
Airworthiness Manual (AWM), Chapter 537, Airworthiness Standards, Appliances, Subchapter B, Technical Standard Orders (TSOs) 537.103 contains a list of adopted United States TSOs in Canada. This may be referenced by internet at:
http://www.tc.gc.ca/civilaviation/regse ... 5/menu.htm
Procurement of Reference Publications
TSOs referenced in this CBAAC may be purchased from:
Superintendent of Documents
U.S. Government Printing Office
Washington D.C. 20402
And by internet at: http://www.faa.gov/avr/air/air100/tsocur/Current.htm or at: http://av-info.faa.gov/redirects/tso.htm
AWM Chapter 551, Aircraft Equipment and Installation, may be referenced at:
http://www.tc.gc.ca/civilaviation/Regse ... Standards/
Chapter551.htm
TERMINOLGY
TAWS
TAWS - Terrain Awareness Warning System
GPWS - Ground Proximity Warning System
Mode 1: Excessive Descent Rate
Mode 2: Excessive Terrain Closure Rate
Mode 3: Altitude Loss After Takeoff
Mode 4: Flight Into Terrain
Mode 5: Excessive Deviation Below Glideslope
Mode 6: Advisory Call-outs, Bank Angle and Altitude (not regulated, but certified for intended function)
Mode 7: Windshear (Federal Aviation Administration (FAA) regulated, aircraft certified for intended function)
FLTA - Forward Looking Terrain Avoidance (TAWS look ahead function)
PDA - Premature Descent Alert (TAWS alert if aircraft is hazardously below the normal approach path for the nearest runway)
Class A TAWS = GPWS (Modes 1 to 5 only) + FLTA + PDA (formerly Honeywell trade name EGPWS, Enhanced GPWS)
Class B TAWS = Modes 1 and 3 only + FLTA + PDA
ACAS
ACAS - Airborne Collision Avoidance System
TCAS - Traffic Alert and Collision Avoidance System
Note: The acronym ACAS can be used interchangeably with TCAS. ACAS is International Civil Aviation Organization (ICAO) terminology, TCAS is FAA terminology. ACAS is going to be used predominantly throughout this advisory circular because the proposed Canadian regulations use the acronym ACAS.
TA - Traffic Advisory - aural and visual alerts and information on position of other aircraft in immediate vicinity
RA - Resolution Advisory - aural and visual alerts and information to avoid a potential airborne collision
TCAS I - TCAS providing TA only
TCAS II - TCAS providing TA and RA
(TCAS II has two prevailing software standards, namely Software (SW) version 6.04a and 7.0. TCAS II with SW version 7.0 is also referred to as ACAS II.)
BACKGROUND
TAWS
TAWS equipment provides aural and visual alerts (both cautions and warnings) to flight crew when the path of the aircraft is predicted to collide with terrain (in some systems, also with obstacles), and this allows flight crews sufficient time to take action. CFIT is an accident or incident in which the airplane, under the flight crew’s control, is inadvertently flown into terrain, obstacles, or water without either sufficient or timely flightcrew awareness to prevent the event.
CFIT is a leading cause of fatalities in airline accidents worldwide since the collision with terrain usually results in total destruction of the aircraft. CFIT is a significant hazard in mountainous terrain, such as that found in many regions of Canada, where a navigational error can have a disastrous outcome. Some airline operators have begun to voluntarily install TAWS equipment because of its demonstrated safety benefits, and its effect on insurance premiums.
TAWS equipment provides a significant improvement over older technology GPWS, and has been proven to alert flight crew to hazardous situations. ICAO has issued standards to require the installation of TAWS equipment on most aircraft in commercial and general aviation operations. The United States FAA also has comprehensive regulations requiring TAWS equipment for commercial and non-commercial operations.
The proposed TC regulations for TAWS were developed in recognition of the safety benefits of TAWS equipment, and to harmonize with regulations in place with organizations noted above, namely, the ICAO and FAA, as well as the Mexican Dirección General de Aeronáutica Civil. Furthermore, the TC regulations were developed in response to a Transportation Safety Board (TSB) recommendation for the installation of TAWS equipment. The new regulations for TAWS will supersede the regulatory requirement for GPWS under the current Subpart 605 of the CARs regulations (Section 605.37).
ACAS
ACAS equipment alerts flight crews when the path of the aircraft is predicted to collide with that of another aircraft and includes aural and visual alerts and cockpit displays of other traffic. The two major classes of ACAS equipment are TCAS I and TCAS II. TCAS I provides a display of other traffic and aural and visual alerts only. TCAS II, in addition to the capabilities of TCAS I, provides guidance to flight crews to avoid collision with other transponder equipped aircraft.
The proposed TC regulations for ACAS were developed in recognition of the safety benefits of the equipment, and with the goal of having similar regulations in place as ICAO and the FAA. Furthermore TC regulations were developed as an outcome of a TSB recommendation for TC to analyze the benefits of ACAS for commercial passenger carrying aircraft.
POLICY DEVELOPMENT
TAWS
New NPAs containing regulations and standards were accepted for TAWS for aeroplanes operating under Subparts 703, 704 and 705 of the CARs. New NPAs were also accepted under Subpart 605 of the CARs for Aircraft Equipment Requirements, which will compel certain aeroplanes operating under Subpart 604 of the CARs to be equipped with TAWS. These NPAs were intended to supercede a previous NPA that was under regulatory review. The new NPAs address additional technical issues and allow relief in the regulations for certain types of operations (e.g. VFR only operations) not considered in the original NPA.
The proposed TC regulations and standards will require one of two classes of TAWS equipment, depending on the aeroplane seating configuration and type of operation. This is in consideration of the safety benefits of the class of TAWS equipment to prevent CFIT accidents, balanced against the cost of this equipment. The regulations and standards include a provision that the TAWS equipment provides adequate warning in common Canadian operating conditions of low temperatures and barometric pressures. They also have provisions to relieve operators from equipping with TAWS, if they operate exclusively in day Visual Flight Rules (VFR) conditions (Subpart 703, 704 and Subpart 605 of the CARs).
Class B TAWS meeting design requirements of FAA TSO C-151, or later versions, will be the minimum acceptable standard of TAWS equipment for Subpart 703 of the CARs, aeroplanes used in Air Taxi Operations configured with 6 or more passenger seats (excluding any pilot seat) and Subpart 704 of the CARs, aeroplanes used in Commuter Operations with 6 to 9 passenger seats. Class B TAWS will also be the minimum standard of TAWS under the Subpart 605 of the CARs regulation for turbine-powered aeroplanes configured with 6 or more passenger seats. (This will compel affected aeroplanes operating under Subpart 604 of the CARs to be equipped accordingly). Class A TAWS per the TSO, will also be satisfactory for these aeroplanes.
Class A TAWS meeting design requirements of FAA TSO C-151, or later versions, and a Terrain Awareness Display, will be required for Subpart 704 of the CARs, aeroplanes used in Commuter Operations configured with 10 or more passenger seats and for all Subpart 705 of the CARs, aeroplanes used in Airline Operations.
All TAWS equipment installations will be in accordance with applicable Canadian airworthiness requirements contained in Chapter 551 of the AWM, including additional approved (non-barometric) altitude inputs, to ensure that TAWS has the required vertical accuracy. This will ensure that TAWS functions correctly in the Canadian operating environment, during non-standard cold atmospheric temperature conditions, and when operating in standard pressure regions. All operators will also be required to ensure that the TAWS equipment terrain and airport database are compatible with the area of operations.
TAWS will not be required for aeroplanes conducting day VFR operations under Subparts 703 and 704 of the CARs as well as under Subpart 605 of the CARs regulation. This is because of incompatibilities between the TAWS alerting envelopes and the minimum altitudes permitted by the regulations for en-route obstacle clearance.
Table 1 (Annex A) summarizes all of the above information on TAWS.
ACAS
New NPAs containing regulations were submitted for ACAS equipment for aeroplanes operating under Subparts 702, 703, 704 and 705 of the CARs. These NPAs were intended to supercede a previous NPA that was under regulatory review.
The earlier regulatory proposal for ACAS was in harmony with the criteria in upcoming ICAO Standards and Recommend Practices (SARPs). The new NPAs are intended to be more in harmony with existing and proposed FAA regulations for TCAS. The high cost of the ACAS equipment on the Aerial Work, Air Taxi and Commuter operations was also reviewed. The new regulations provide revised criteria for suitable ACAS equipment matched to the aeroplane weight, power plant and operation that balance the safety benefits with the cost of the installation.
TCAS I will be the minimum acceptable collision avoidance system for large aeroplanes (Maximum Certificated Take-off Weight (MCTOW) greater than 12,500 lbs/5,700 kgs) operating under Subpart 703 of the CARs, Air Taxi and Subpart 704 of the CARs, Commuter operations.
TCAS II (SW version 6.04a) and a mode S transponder, will be the minimum acceptable collision avoidance system for turbine-powered aeroplanes operating under Subpart 705 of the CARs, Airline operations, and for turbine-powered aeroplanes with a MCTOW exceeding 33,000 lbs/15,000 kgs operating under Subpart 702 of the CARs (turbine powered land aeroplanes only) and Subpart 704 of the CARs.
TCAS II (ACAS II SW version 7.0) and a mode S transponder will be the minimum acceptable collision avoidance system for all aeroplanes, operating under Subparts 702, 703, 704 and 705 of the CARs requiring ACAS equipment by the new regulations, when operations are conducted in Reduced Vertical Separation Minima (RVSM) airspace.
Table 2 (Annex B) summarizes all of the above information on ACAS.
ACTION
IMPLEMENTATION DATES
TAWS
The new TAWS regulations will be effective for newly manufactured aeroplanes on the date the regulations are promulgated. This also applies to newly manufactured aircraft that enter Canada on a lease back arrangement. All aeroplanes will have to be in compliance two years after the date the regulations are promulgated. For the purposes of future planning, the Minister will contemplate delaying the implementation to not earlier than September 30, 2008. All aeroplanes will have to be in compliance with the TAWS altitude accuracy requirements 5 years after the date the regulations are promulgated. Again, for the purposes of future planning, the Minister will contemplate delaying the implementation to not earlier than September 30, 2010.
Section 605.37 of the CARs is being amended to no longer require GPWS equipment for all aeroplanes, to coincide with the date all aeroplanes will have to be equipped with TAWS by the new regulations.
ACAS
The new ACAS regulations will be effective for newly manufactured aeroplanes on the date the regulations are promulgated. All aeroplanes will have to be in compliance two years after the date the regulations are promulgated.
FUTURE DISPOSITION
TC is committed to maintaining a viable civil aviation transportation system, while not compromising safety. This CBAAC will remain in effect for information purposes until further notice.
CONCLUSION
This CBAAC brings to the attention of air operators the current status and implementation dates of applicable regulations of TAWS and ACAS.
Michel Gaudreau
Director
Commercial and Business Aviation
