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Project Leader: Miles Gore Brown
Project OS 13/03 - Amendment of CAO 20.7.1B and CAO 20.7.4
Project closed 15 October 2014.
Project completed following the making of CAO 20.7.4 Amendment Instrument 2014 (No. 1) and CAO 20.7.1B Amendment Instrument 2014 (No. 1) on 15 May 2014. CASA issued NFRM OS 13/03 to conclude consultation on these amendments.
The amendment includes:
- Amendment of CAO 20.7.1B and CAO 20.7.4 to account for jet aeroplanes with maximum takeoff weight between 6,000 lb and 12,500 lb.
- Amendment of CAO 20.7.1B to allow credit for:
- RP departure capabilities
- Use of Operational Landing Distances
- Use of increased bank angles during take-off with one engine inoperative.
The US FAA has always required small jet airplanes to have performance information based on the standards for the transport category, even though transport category certification is not essential for such airplanes. In 2009 the FAA announced it would formalise this long-term practice by requiring jet airplanes with MTOW between 6,000 lb and 12,500 lb to have performance information based on the standards for the commuter category (which are very similar to the standards for the transport category.)
- CAO 20.7.4 specifies weight and performance limitations for aeroplanes of MTOW not above 5700 kg. CAO 20.7.4 does not distinguish between jet and propeller-driven aeroplanes. The content of CAO 20.7.4 is not appropriate for jet aeroplanes type-certificated by the FAA.
- CAO 20.7.1B specifies weight and performance limitations for aeroplanes of MTOW above 5700 kg. These limitations are compatible with the performance information supplied with jet aeroplanes, including jet aeroplanes type-certificated by the FAA to an MTOW not above 12,500 lb (5670 kg.)
Australian operators and pilots of small jet aeroplanes face uncertainty about how to operate in accordance with CAO 20.7.4. There are inconsistencies in the ways CASA's Regional Offices are applying CAO 20.7.4 to the weight and performance of small jet aeroplanes. Australian operators are expected to use the foreign flight manual without any uniquely-Australian adjustments.
The primary issue is the problem with inappropriate requirements. The inconsistency between CAO 20.7.4 and the performance information in the flight manuals of these aeroplanes is potentially a safety risk.
There are presently approximately twenty-two small jet aeroplanes on the Australian register that are affected by this problem. This number is expected to increase in the future. Safety of operation of these aeroplanes is potentially reduced because of the uncertainty about weight and performance limitations. In the event of an incident or accident involving one of these small jet aeroplanes, any investigation could potentially identify the lack of precision in CAO Part 20.7 as being a contributing factor.
If no action is taken to clarify the present uncertainty in CAO Part 20.7 there will continue to be inconsistencies in CASA's expectations of operators of these small jet aeroplanes.
Aeroplanes flying certain take-off flight paths designed to Required Navigation Performance (RNP) criteria are able to be navigated with lateral obstacle clearance less than that currently required for compliance with CAO 20.7.1B. A re-evaluation of the method of providing for the evaluation of obstacles in the take-off path is warranted in order to recognise the improved accuracy and safety of RNP - Authorisation Required (AR) departures. This aspect of the project has been initiated in response to a request from a regular public transport operator.
Subsection 12 of the CAO was amended in the late 1990s to allow operators the option of either continuing to use the then existing takeoff-climb requirements or using those of ICAO Annex 6 Part I. The subsection was further amended in 2005 to allow for a limited use of RNP departures and the intention is to build on this option. Provisions currently in the CAO will be retained for operators whose aeroplanes are not equipped for RNP operations or who do not wish to take advantage of the hew provisions.
Industry participants in the consultation process for CASR Part 121 have also raised for discussion the topics of landing field length and bank angle limitations.
- In 2011, Airbus will introduce a new reference for in-flight landing distance assessment, both with an without in-flight failures. The new distances, called Operational Landing Distances (OLD), are a realistic representation of operational achievable landing performance. This new set of performance information is part of a proposal developed by the FAA Aviation Rulemaking Committee for Takeoff and Landing Performance Assessment (TALPA ARC). Project CS 10/09 will consider this material for possible inclusion into the amended CAO 20.7.1B to address future requirements for in-flight landing assessments.
- CAO 20.7.1B will also be amended to allow planning for increased bank angles with one engine inoperative, as permitted by EU-OPS 1.495.
Since the 1970S, airline operators in Australia have been required to reduce the length of the runway by a distance known as line-up allowance. This procedure is to allow for the distance used in taxiing into the runway and lining-up prior to setting thrust for take-off.
This safety precaution was originally proposed to the International Civil Aviation Organization (ICAO) by Australia. Line-up allowance is now one of the standards in ICAO Annex 6, Part I:
22.214.171.124: In determining the length of the runway available, account shall be taken of the loss, if any, of runway length due to alignment of the aeroplane prior to take-off.
A requirement for line-up allowance was proposed for CASR Part 121 in April 2002 in NPRM 02011OS (page A30). Incorporation of line-up allowance in CASR Part 121 was agreed in 2002.
The objective of the project is to amend CAO Part 20.7 in two places to make the Part compatible with the performance information published in the flight manuals of the small jet aeroplanes.
CASA has regulatory policy in place. It is expected that legislation will require each aeroplane to be operated in accordance with the weight and performance limitations specified in its Flight Manual.
If none of these small jet aeroplanes are being used in regular public transport operations no other document will require amendment. (There is no CAAP or Advisory Circular supporting CAO 20.7.1B or 20.7.4.)
If one or more of these small jet aeroplanes are being used in regular public transport operations it will be desirable to amend CAO 20.7.2 and CAAP 235-3(0).
Suitable provisions are planned for CASR Parts 91 and 135 to give CASA the power to specify performance requirements that apply to aeroplanes. In using these provisions, CASA will ensure that the performance requirements applied to small jet aeroplanes will be compatible with the performance information in the aeroplane's flight manual.
The objective of this part of the project is to amend CAO Section 20.7.1B subsections 2, 11 and 12 in order to allow operators of suitably equipped aeroplanes to - allow operators of suitably equipped aeroplanes to take advantage of the capability to use reduced lateral obstacle clearance during take-off climb, and increased bank angles; and
- align landing distance requirements with international practice, and allow operators of aircaft with information about Operational Landing Distance to make use of that information.
The amendments to the Order will be incorporated in the equivalent regulations of CASR Part 121.
The objective of this part of the project is to amend CAO Section 20.7.1.B to direct pilots and operators to adjust the dimensions of the runway to account for the distance to align the aircraft on the runway prior to initiating take-off.
The amended terms of reference for this project was approved by Peter Boyd, Executive Manager Standards Development & Future Technology Division on 24 November 2011.
CAO 20.7.1B and CAO 20.7.4
Project Leader: Miles Gore Brown
Project Sponsor: Rick Leeds, Manager Airworthiness & Engineering Branch
Standards Development Project Manager: Miles Gore Brown
- Briefing Document - Proposed Amendments to CAO 20.7.4 and CAO 20.7.1B
- Explanatory Statement - Proposed CAO 20.7.4 Amdt Instrument 2013 (No. 1)
- Proposed DRAFT CAO 20.7.4 Amdt Instrument 2013 (No. 1)
- Explanatory Statement Proposed CAO 20.7.1B Amdt Instrument 2013 (No. 1)
- Proposed DRAFT CAO 20.7.1B Instrument Amdt Instrument 2013 (No. 1)
- Draft CAAP 20.7.1(0)
This Consultation Draft closed for comment 31 May 2013.
28 May 2014
- CAAP 235-5(0) - New performance provisions for CAO 20.7.1B and CAO 20.7.4
View the project history.