Narrative:

After takeoff we were flying the cottonwood 2 departure which has a single engine route and once parameters are met you can vacate the departure and go to jesie intersection. We took off with the LNAV and autopilot engaged and the aircraft was flying the route. We were getting ice messages and a moderate workload when ATC asked us to start our turn toward jesie. We had already met the parameters to turn but we missed the turn in a timely manner. We were then asked to contact ATC and tell them why we missed the turn.this departure has you start off by flying a single engine route and then transition to a two engine route. I believe that this is totally opposite of all other sids and pilot training. Our aircraft FMS will always load the full single engine route and that is what we should fly in a mountainous area. Between the workload and the design of this SID it lends itself to this mistake by design. ATC advised they had a lot of aircraft doing the exact same thing we did and the aircraft continues on the single engine route and not the two engine turn. Our aircraft is highly automated and this SID does not fit into an automated departure. I feel that a simple ATC instruction by ATC like cleared for takeoff and at 12000 ft cleared to jesie would solve some of this as well. In my opinion this SID should be revised since ATC is receiving repeated errors of the same kind. No safety of flight was compromised but we were on course to fly the full single engine route because we failed to override our automation and turn sooner toward jesie.

Google
 

Original NASA ASRS Text

Title: G550 Captain reported their FMS data directed the aircraft to the wrong fix while transistioning from the single engine to dual engine route on the Cottonwood 2 SID out of EGE.

Narrative: After takeoff we were flying the Cottonwood 2 departure which has a single engine route and once parameters are met you can vacate the departure and go to JESIE intersection. We took off with the LNAV and autopilot engaged and the aircraft was flying the route. We were getting ice messages and a moderate workload when ATC asked us to start our turn toward JESIE. We had already met the parameters to turn but we missed the turn in a timely manner. We were then asked to contact ATC and tell them why we missed the turn.This departure has you start off by flying a single engine route and then transition to a two engine route. I believe that this is totally opposite of all other SIDs and pilot training. Our aircraft FMS will always load the full single engine route and that is what we should fly in a mountainous area. Between the workload and the design of this SID it lends itself to this mistake by design. ATC advised they had a lot of aircraft doing the exact same thing we did and the aircraft continues on the single engine route and not the two engine turn. Our aircraft is highly automated and this SID does not fit into an automated departure. I feel that a simple ATC instruction by ATC like cleared for takeoff and at 12000 ft cleared to JESIE would solve some of this as well. In my opinion this SID should be revised since ATC is receiving repeated errors of the same kind. No safety of flight was compromised but we were on course to fly the full single engine route because we failed to override our automation and turn sooner toward JESIE.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.