1. JAA TGL 10 Explained D J Hawkes UK CAA
2 Joint Aviation Regulation OPS 1.243 Operations in areas with specific navigation performance requirements:
3 Joint Aviation Regulations
4 Guidance Leaflet No. 10 Published by JAA on 1st November 2000 to support the European P-RNAV strategy.
Supplemented by FAQs published April 2003.
5. TGL-10 Main Topics
6 Assumptions- about P-RNAV The design of terminal P-RNAV procedures:
is consistent with the relevant parts of ICAO Doc 8168 PANS OPS ;
follow the guidelines of EUROCONTROL document NAV.ET1.ST10;
is based upon WGS 84 co-ordinates;
is validated and shown to be aircraft compatible.
7 Further Assumptions Fix data is provided on charts to assist integrity checking by the flight crew;
NOTAMs for non-availability of a procedure;
Where needed to address specific hazards, dual P-RNAV systems is stated in the AIP;
The AIP addresses radar service if needed;
RT phraseology for P-RNAV has been promulgated;
Non ICAO compliant navigation aids are excluded from the AIP, e.g. TACAN.
8 Aircraft Systems for P-RNAV P-RNAV may be based the following types of sensor to give lateral navigation along a path defined by waypoints from on-board navigation database:
Distance Measuring Equipment using two or more beacons (DME/DME);
Global Navigation Satellite System (GNSS);
Co-located VOR/DME provided the requirements of the procedure are met.
Inertial Systems (INS or IRS) with automatic radio updating.
9 Other Aircraft Systems LORAN C is not an acceptable sensor;
VNAV capability is optional;
The navigation database may hold TACAN data to supplement DME provided the TACAN beacon meets ICAO Annex 10 Standards and is listed in the AIP.
10 System Performance- Accuracy The lateral track keeping accuracy of the on-board P-RNAV system shall be equal to or better than +/- 1 NM for 95% of the flight time.
Track keeping accuracy depends on the navigation system error (a combination of path definition error, position estimation error and display error), and the Flight Technical Error (FTE). It corresponds to the accuracy component of RNP-1 and RNP-1 RNAV.
11 Meeting the accuracy requirement- GPS For manual flight, a default FTE of 0.8 NM may be assumed (ref. RTCA DO-283, 18.104.22.168).
For GPS, provided the path definition and display errors are negligible, manual flight using GPS can achieve the required accuracy.
For non-GPS cases, positioning error is more significant, so flight director or autopilot is necessary to reduce FTE and to achieve the required accuracy.
Also, a suitable map display can reduce FTE.
12 RNAV systems using DME/DME and compliant with the 2D navigation accuracy criteria of FAA AC 90-45A, AC 20-130(), FAA TSO-C115(), or JAA JTSO-2C115(), can be used for P-RNAV procedures meeting the published criteria without further evaluation of system accuracy.
However, compliance with all other criteria of TGL 10 will need to be shown.
Meeting the accuracy requirement- DME/DME
13 Evidence of meeting accuracy criteria Options include:
A Flight Manual statement;
A statement from the aircraft constructor;
A statement from the equipment installer;
An assessment report.
14 System Performance- Integrity The probability of displaying hazardously misleading navigational or positional information simultaneously to both pilots shall be Remote, as defined in JAR 25.1309.
For P-RNAV in the terminal area, hazardous should be interpreted as involving misleading information without a timely warning and which, in the absence of other cues, is unlikely to be detected by the flight crew.
15 Meeting the integrity requirement The integrity requirements applied at initial aircraft build for primary navigation systems are the same as those for P-RNAV, no further investigation is required.
Compliance may be claimed on the basis of the original certification.
For modified aircraft, a statement should be sought from the equipment installer.
16 System Performance- Continuity of Function For the on-board systems, it shall be shown that:
The probability of loss of all navigation information is Remote*.
The probability of non-restorable loss of all navigation and communication functions is Extremely Improbable*.
* as defined in JAR 25.1309.
17 Meeting Continuity of Function criteria In addition to the equipment required by JAR-OPS 1, Sub-part L for IFR flight (or equivalent national requirements), at least one area navigation system is required.
19 Objectives P-RNAV capability;
Appropriate controls and displays to avoid confusion and crew errors;
Low crew workload compatible with TMA operations;
20 TGL 10 Table 1: Required functions System display requirements;
Parameters to be displayed;
Use of the navigation database;
Auto-tuning and navaid selection;
Automatic leg sequencing;
Fly-over and fly-by turns;
Use of ARINC 424 path terminators;
Automatic reversion after primary nav sensor failure.
21 Specific issues- Course Selection Automatic course selection slaved to the RNAV computed path is necessary to ensure accurate track keeping with an acceptable crew workload during a complex P-RNAV procedure.
Automatic selection will be required for all new installations.
If this function is not provided in existing installations, track keeping & crew workload will need to be assessed on a case-by-case basis.
22 Specific issues- Deviation Scaling The deviation display shall have a full-scale deflection suitable for the phase of flight and the required track keeping accuracy.
Scaling may be set automatically to a default value, or obtained from a database.
The full-scale deflection value must be known or made available for display to the flight crew.
For P-RNAV operations, a value of ±1 NM is acceptable.
23 Specific issues- MAGVAR To ensure accurate navigation, the magnetic variation tables held in the system (e.g. IRS or FMC or Navigation computer) need to be current.
Updates should be requested from the equipment supplier.
24 Specific issues- Dual Systems and Intermixing of equipment For approach operations, to avoid problems of conflicting methods of operation and conflicting display formats, intermixing of RNAV equipment is not permitted.
The following must be consistent:
Units and notation of displayed data;
25 TGL 10 Table 2: Recommended functions Parallel offset paths;
Autopilot/Flight Director* coupling;
Automatic runway position update;
Additional ARINC 424 path terminators;
26 Airworthiness Compliance- New installations Submit a compliance statement to your authority that shows how the criteria of TGL 10 have been satisfied. Address:
System safety analysis;
Software assurance level;
System failure scenarios;
Autopilot/Flight Director coupling;
Execution of leg types.
27 Airworthiness Compliance- Existing Installations Submit a compliance statement to your own authority that shows how the criteria of TGL 10 have been satisfied. Compliance may be established by inspection of the installed system to confirm the availability of required features and functionality.
The performance and integrity criteria may be confirmed by reference to statements in the Aircraft Flight Manual or to other applicable approvals and supporting certification data.
28 Aircraft Flight Manual- new or modified aircraft If a description of the installed system with related operating instructions and procedures are available in other approved operating or training manuals, the AFM may need only the following information:
A statement which identifies the equipment and aircraft build or modification standard certificated for P-RNAV operations with an RNP-1 or better capability.
29 AFM- Existing aircraft If the AFM or Pilot’s Operating Handbook is unclear about the system capability, the operator has one of the following options:
30 Operational Criteria An operational evaluation will need to confirm the adequacy of normal and contingency procedures for the particular equipment installation.
Operational approval will be stated in the applicable Air Operator Certificate, or issued in accordance with national procedures, as appropriate.
31 Flight Crew Procedures & Training TGL 10 provides advice on:
Flight progress monitoring;
Contents of training manuals.
32 Navigation Databases The navigation database should be obtained from an approved supplier who has complied with EUROCAE/RTCA document ED-76/DO-200A, Standards for Processing Aeronautical Data.
Until such approved suppliers become available, as a minimum, the operator must implement integrity checks to verify data relating to waypoints below the applicable minimum obstacle clearance altitude.