Hypothetical scenario: when is the PF allowed to "hand fly" a SID? The graphical depiction has what appears to be a graduated turn to the first navaid from the runway. However, RNAV is not in the title nor is it a "Pilot NAV" DP. There is no obstacle issue at this airport, and not a Radar DP.

Can someone point me to the FAR, AIM or other pub which explains better in what cases it is ok to manually fly versus allowing the jet to do it? After a standard rate turn to intercept the correct radial, the aircraft appeared to be on the inside of the ground track depicted by the FMS, which leads one to believe they may not be inside protected airspace. If the FMS was coupled to the A/P, the aircraft would have followed the line exactly.

 

Why couldn't you? Stay on the course and you're good. I've never heard an argument requiring AP use on a SID.

 

I've heard of this, some airlines require this.

 

There are no FARs requiring AP usage for a SID. As others have mentioned, your company may require it.

 

There might be some issues with advanced RNP (not RNAV) procedures, I had a class on this recently but id have to do some research to find out for sure. Has to do with the required performance and error assuming centerline (as indicated) is maintained, requiring autopilot. Otherwise being say 1/2 deflection off with position error may be outside the safe limits for terrain clearance.

 

Most likely this is a company specific SOP thing. However, it could be something more technical, such as Special Instrument Procedures or Tailored procedures that are company specific.

Some procedures have "Terps Waivers" of criteria because of terrain, etc. Aspen for example has at least one procedure with 6 Terps waivers. Anytime you see unusual notes, such as "maximum speed 190 between xxxxx and yyyyy" that is a risk mitigating procedure to offset the Terps waiver of criteria. You might have another procedure which requires a precise track to be flown. The risk mitigating procedures (Developed by the FAA's AeroNav Procedure Team and reviewed by AFS-400 and the NextGen Branches) might include that the procedure note says "Use of Autopilot/LNAV Mode required"

Without getting too far in the weeds, this is all technical Part 77 Terps stuff described in the FAA's 8260.XX Series Orders.

 

Discussed with an instructor, issue resolved. As mentioned above, in this particular case it's a conventional SID which does not fall into any of the other categories: RNAV, ODP, SDP, etc. FMS addicts, myself included, may feel obligated to fly the command bars to maintain what the box defines as the ground track, but there is nothing preventing an aircraft from flying raw data to join the first radial. No specific company policy in this case.

While AIM 5-2-10 makes mention on "maintaining lateral ground track" no where is it defined what that is or what the obstacle clearance is on either side of the TERPSed area. If obstacles/terrain were an issue, an ODP would have been used. If the TERPSter had wanted aircraft to fly a specific ground track for another reason, it would have been an RNAV DP.

The fact that the conventional SID can pulled from the database is more of a convenience.

Thanks for the responses. Learning has occurred!

 

Most departures, I prefer to hand fly until either bored or in RVSM. I don't think I've ever flown a departure that specified autopilot use.

 

For non-RNAV departures, there is no requirement for automation of any kind (A/P, FD, LNAV etc.).

For RNAV 1 departures, AC 90-100A, item 10 provides guidance for flight crew operating procedures. It states in paragraph (9): Pilots must use a lateral deviation indicator (or equivalent navigation map display), flight director and/or autopilot in lateral navigation mode on RNAV 1 routes. Lateral mode guidance should be engaged no later than 500 feet.

AC 90-105 covers RNP 1 departure procedures, and the flight crew guidance is the same as RNAV 1 departures.

Furthermore, both AC 90-100A and 90-105 state:
For normal operations, cross-track error/deviation (the difference between the RNAV system computed path and the aircraft position relative to the path) should be limited to ± ½ the navigation accuracy associated with the procedure or route (i.e., 0.5 nm for RNAV 1, 1.0 nm for RNAV 2). Brief deviations from this standard (e.g., overshoots or undershoots) during and immediately after procedure/route turns, up to a maximum of 1 times the navigation accuracy (i.e., 1.0 nm for RNAV 1, 2.0 nm for RNAV 2), are allowable.

While autopilot isn't required for an RNAV or RNP procedure, it might be a good idea depending on the departure, as some now include RF legs.

RNAV 1 departures require the accuracy of RNP 1. However RNP 1 departures, in addition to the RNP 1 accuracy requirement, also have a containment of RNP 2 (2x the RNP) and a crew alerting and monitoring requirement. This containment width is what the used for terrain clearance.

 

^^^^What He Said^^^^

Just to piggyback a bit, Advisory Circulars are not regulatory, just recommendations.