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How Databases Are Used . FMS
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1. Coding RNAV ProceduresWhat the Datahouses need from the Designers Sorin Onitiu Data Standards
P-RNAV Workshop Amsterdam, 22-23 June 05
DS department created to ensure that Jepp Aviation Database entry and extract methods are complying with industry database standards as ARINC 424, RTCA 200A/201A. DS works closely with airline, avionics, manufacturers, government AIS/PD offices, international organizations. DS department created to ensure that Jepp Aviation Database entry and extract methods are complying with industry database standards as ARINC 424, RTCA 200A/201A. DS works closely with airline, avionics, manufacturers, government AIS/PD offices, international organizations.
2. How Databases Are Used
3. ARINC 424 Path & Terminators(short considerations)
Description of Leg Types introduces the Path/ Terminator Concept:
Path logically describes how the aircraft gets to the Terminator (track, course, heading);
Terminator is the event or condition (fix, altitude, distance, manual) that causes the system to switch to the next leg;
ARINC 424 Specifications (-18) will separately include
(Attachment 6) RNAV Coding Rules (SID/STAR and Approach Procedures) by using the selected 13 P/Ts (as of today) from the 23 total path terminators;
There are two types of rules: General and Specific; where a
contradiction exists between a general and a specific rule, the specific rule must be used.
4. RNAV P/T Legs (13 selected) Some insight into the FMS requirements and Leg Data Field
5. RF Leg (Radius to a Fix) Path = Radius around Fix; Terminator = Fix on radius;
Requires 3 fixes: termination fix built in radius, origination fix built in radius and radius fix, lines (previous & next segment) tangent to the arc;
Does NOT require a navaid as the arc origin;
RF is generally preceded and followed by TF legs (tangent to the arc);
RF leg coded when procedure type designed with RF Constant Radius Turn capability as a design criteria;
Leg Data Field:
NO Over-fly Flag for BOTH origin/termination fix;
TD, Arc Centre required; Radius proposed to be required in Attach 6 (useful to have info on charts and/or AIP description);
Along Track Distance required (useful to have info on charts
)
6. CA Leg (Course to Altitude) Difference between CA and VA is in cross-wind situation:
VA leg - slower acft will crosswind with a greater displacement as the faster airplanes;
CA leg the crab angle is adjusted so that all aircraft will fly the same track over the ground;
On CA leg, the terminator is still at an undefined position; the Along Track Distance of the leg termination will be a function of aircraft performance and environmental conditions
Leg Data Field:
TD and TDV and Speed limit are optional;
Altitude Termination is always AT or ABOVE;
NO Recd NAVAID required
7. DF Leg (Direct to Fix) The DF leg is the leg used when you start at an unspecified position (f.e. previous leg had an over-fly)
Its construction is essentially similar to the TF leg: at the time of the direct entry, the present position is stored and used as the From waypoint and the system will then fly the great circle course defined by that location and the specified To waypoint;
Leg Data Field:
Over-fly flag required for CF/DF, DF/DF and TF/DF combo, otherwise optional;
TD optional (no TDV required);
8. FA Leg (Fix to Altitude) Begins at a fix, a defined set of coordinates and flies a specified course until the terminating altitude is reached;
Difference between CA leg and an FA leg is the FA specifies a course from a fix vs. simply fly a course (one FA course 080°, many parallel CA courses 080°);
Terminates at an unspecified position along the course;
Leg Data Field:
1. Recd NAVAID, Theta/Rho values are required (optional proposed in draft of Attachment 6)
TD/TDV optional;
3. Altitude Termination always AT or ABOVE
10. Manual Termination Legs included in RNAV primarily as ending leg of STARs & Missed Apch and in the definition of SIDs initial climb-out with ATC intervention It is NOT the intent to endorse manual termination legs within the body of a procedure.
FM leg
Will not provide an automatic leg
sequence (manual intervention to
the next leg);
Permits pilot to respond to course vectors while leaving the FMS displayed on the instrument and coupled to the flight control system;
Leg Data field:
Wpt Ident & Course required;
TD/TDV, Recd NAVAID (proposed optional), Alt & Speed limit optional;
Over-fly flag set at the fix: N/A;
VM leg
Typical use: Climb rwy heading expect vectors;
Permits pilot to respond to heading vectors while leaving
Leg Data Field:
Wpt Ident optional; Heading required;
2. TD/TDV optional; Recd NAVAID N/A;
11. TF Leg (Track To Fix)
Requires 2 fixes: previous leg must end at fix A, then track to fix B;
Yields a path that is the great circle path btn 2 wpts; since the course is calculated based on lat/long, true courses rather than magnetic will result (system Mag Var model adjusts the desired track to display on the pilots instrument, but will have NO influence on the acft path over the Earth);
Easiest to implement because the database reqs are minimal;
Leg Data Field:
Over-fly only required for TF/DF combo, otherwise optional;
TD/TDV, Recd NAVAID, Altitude, Speed limit optional (Jeppesen does not use TD/TDV on TF/TF combo)
Path length required only for flight planning purposes
12. CF Leg (Course to Fix)
Specifies an inbound course to location identified by its lat/long;
When starting from an undefined position, recovers the defined course;
Leg Data Field:
Requires Recd NAVAID, Theta/Rho;
2. Requires a route distance;
3. Over-fly the fix for CF/DF combo, otherwise optional;
4. Optional TD/TDV, Speed/Altitude Limit, Vertical Angle
DF leg is bringing the aircraft from the present position to the next fix; flight is outside desired track until the fix.
Explain the difference of Leg Distance and Route Distance DF leg is bringing the aircraft from the present position to the next fix; flight is outside desired track until the fix.
Explain the difference of Leg Distance and Route Distance
13. HF, HA and HM legs HF will sequence legs and exit after one complete circuit; used in lieu of racetrack;
TD (TDV N/A), Time or Dist, inbd course required; for RNP hldg, radius required too;
HA allows for a climb in the holding pattern; on reaching the terminating altitude, the system will cross the holding fix then sequence legs to further proceed on course;
TD (TDV N/A), Time or Dist, inbd course required; Altitude Termination will be AT or ABOVE;
HM leg sequence requires the pilots manual intervention; Go to ABC and hold dont know how long your going to hold
Note: HX legs are part of the procedure; designers should clearly indicate the purpose ! Non-mandatory (by ATC) holding should be not coded with P/T , but with EP records To be mentioned:
1)ARINC solutions for reversal procedures: racetrack (HF); 45°/180° turn (PI + CF to FAF), teardrop (typically FC followed by CF);
2) ICAO/FAA (ARINC) Holding based on timing on outbound vs. based on inbound course;
3) A good example for a HA in a SID is Innsbruck where you have to climb in a valley until a specified altitude to continue enrouteTo be mentioned:
1)ARINC solutions for reversal procedures: racetrack (HF); 45°/180° turn (PI + CF to FAF), teardrop (typically FC followed by CF);
2) ICAO/FAA (ARINC) Holding based on timing on outbound vs. based on inbound course;
3) A good example for a HA in a SID is Innsbruck where you have to climb in a valley until a specified altitude to continue enroute
14. Turn Direction/ Turn Direction Valid TD shall be always indicated whenever the P/T includes a turn such as RF leg;
TD must always be indicated whenever a turn of 90° or more exists between two consecutive legs; the indication is carried on the leg being turned to.
TD and TDV are used in combination to force a particular turn direction whenever the track/heading change exceeds 135°
Explain when a Turn Direction is made (At the beginning of a leg)Explain when a Turn Direction is made (At the beginning of a leg)
16. Waypoint Fly-by/Fly-over requirements
17. Sample (Fly-Over vs. Fly-by)
18. Entry/exit points, FAF over-fly ?
19. RF leg depiction
20. Conventional SID/GPS FMS RNAV Overlay dont need for the exit fix an additional RNAV waypoint
21. Textual description vs. Graphic depiction
22. Collocation of VOR/DME ARINC: VHF Navaid Primary record (D) contains: VOR Lat/Long, DME Lat/Long and Navaid Class;
Navaid Class field provides in a coded format: the type, usable range/power, navaid signal info and collocation in both an electronic and aeronautical sense;
For VHF Navaids, the character N in column 32 of record is entered if either the Lat and/or Long of the VOR and collocated DME of a freq paired VORDME differ by 1/10 arc minutes or more;
23. ICAO Collocation Limits for a DME associated with VOR ANNEX 10:
Co-axial VOR and DME located on the same vertical axis;
Offset collocation:
For approach purposes and procedures requiring highest accuracy: antennas NOT exceeding 30m(100ft);
For Doppler VOR + separate DME: between 30 and 80m(260ft);
3. For en-route purposes, antenna separation have not to exceed 600m(2000ft);
We need to have in the State source BOTH sets of coordinates even if physically collocated or not !
Remark: Collocation in respect of ICAO (over 6 difference )will limit the selection of the Recd Navaid for SID/STAR coding purposes.
24. Altitude and Speed restrictions
25. Recommended Navaid Specific Path Terminators require a Recommended Navaid;
In the FMS world, the Recd Nav is where the system gets its magnetic variation from; the FMS calculates everything in true bearings attempting to present its calculations in reasonable magnetic values to the pilot;
Some new FMSs have started using a Earth model instead (values differing from those charted & in database);
ARINC 424 provides little or no guidance on selecting navaids for Recd Navaid (except for final approach coding rules)
Legs requiring Recd Nav will be not greater than 60NM (arrival/dep) and 40NM for approaches;
For SID/STAR, Recd Nav may be any collocated (within 6 arc seconds) VORDME/VORTAC (ARINC field 5.23);
If RNAV procedure ends in a conventional procedure (RNAV STAR to ILS or RNAV transition to ILS), the LOC navaid will be referenced;
26. SID Identification
28. Tabular data information in the AIP would have to be as follows:
29. What we would need in the AIP (summary) RNAV waypoint uniquely identified (5LNC);
No DME fix or Radial Int requiring additional CNFs;
We encourage the Terminal Wpt naming convention (AAXNN);
Speed/Altitude restrictions applied at the waypoint; situation like below FL100/IAS 250KT not codeable;
Expect altitude not codeable unless associated with a waypoint (by ATC altitude);
TD/TDV should be driven by database provider;
MEAs not coded;
Favourable for the textual & abbreviated procedure description ISO PTs sequence; if PTs given then recommended vs. prescribed;
30. What we would need in the AIP (summary) The textual description is compared with the graphical depiction; there are considered complementary, but if there are small differences, the textual description overrides graphic;
In case of more procedures using a common waypoint needed as Fly-by and Fly-over, propose to have the depiction as Fly-by (default) and specific procedure text clearly defining the flag to be set in coding;
Recd Navaid to be published for consistency; Theta/Rho values could be optionally provided;
31. QUESTIONS ?