Large Transport; Low Wing; 2 Turbojet Eng
Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Situational Awareness
Deviation / Discrepancy - Procedural Published Material / Policy
Environment - Non Weather Related; Company Policy
On the arrival in MGGT; winds were reported out of the south at 10 kts; so MGGT was landing Runway 20. Referencing WSI (Weather Services International); there were two active areas for volcanic ash; one for Pacaya and one for Agua. Both had plumes and ash clouds from the surface to 14;000 ft; and both were moving west. While selecting what approach we were planning; we looked at the different missed approaches and decided the VOR Z Runway 20 would be best in the event of a missed approach and avoid any ash cloud. The Missed Approach procedure for the VOR Z Runway 20 is AUR; 1 DME past the VOR; a slight left turn via the 169 radial to 17 DME and then hold at 11;000 ft with no special climb rates associated with it. Then our briefing turned to the Engine-Out (EO) Procedure. We immediately noticed the EO procedure splits the gap of the volcanos Pacaya and Agua; and right through the SIGMET area.We thought about what to do in the event of an engine-out missed approach. I decided; in this situation; the EO procedure would not be appropriate due to the active SIGMETs for volcanic ash; and I decided the missed approach for the VOR Z Runway 20 would be more appropriate and safer than the EO as published. We reviewed the terrain that shows on the EO procedure; terrain charts; and considered our landing weight. Landing was normal and no missed approach was accomplished. But planning for worse case revealed challenges to our procedures of following company EO procedures as published.Our training has us brief and setup EO procedures for missed approaches as well as takeoff; and fly them as published in the event of an engine-out event. This particular procedure; on this night; sets a crew up for a terrible scenario of going missed approach or takeoff; losing an engine; and flying directly into a volcanic ash cloud with one engine while these volcanoes are active.My suggestion would be to give the aircrews more options; have the EO procedure ready but review all the missed approaches as published and note whether we can fly them as a published engine-out. In this case; I believe we could have safely executed the missed approach for the VOR Z Runway 20; and possibly an engine-out scenario on initial takeoff; but I just don't have access to the information to confirm this. Blindly following EO procedures when other factors encroach on the procedures could result in a worse outcome.
Air carrier Captain reported company policy for single engine missed approach would be through volcanic ash; unless flight crews plan for a different procedure.