Narrative:

Flight was operating to the west coast on a manually built route crossing the rocky mountains in colorado. The fight was originally planned and released with a method 1 (M1) terrain clearance solution. Maintenance deferred an engine anti-ice valve in the open position; so release two was planned and released with MEL 30-21 applied. This new flight plan was planned and released with a method 2 (M2) solution with den and lax as the listed M2 alternates. Once enroute; weather allowed for a more direct routing; so the dispatcher asked the crew to request direct from their present position (over nebraska a bit west of the spawn waypoint) to the bld VOR (located in southern nevada). The crew acknowledged; requested; and was cleared direct to bld; and informed the dispatcher of that fact. Wishing to compute a new flight plan for this new direct route (in order to get new fuel burn and ensure terrain clearance); the dispatcher requested a FMC position report; which was entered in. The dispatcher then put the new route in and computed a flight plan. The error 'no point-circle crossing found for ZZZ' (or something to that effect) was displayed. To correct this error; the dispatcher went to the EROPS tab and clicked 'default' (the flight had been planned with 'prep man' selected and alternate airports of ZZZ; den; and lax). This altered the EROPS solution to alternate airports of lnk; inw; and lax; and produced a solution with no errors (other than perhaps the usual 'insufficient fuel' or similar error that is always generated when calculating an airborne flight). The dispatcher then released the flight with the new direct routing.immediately upon inputting release 3; the dispatcher realized that there was no terrain clearance solution generated. The flight was still east of the rockies at the time and crossing over areas of high terrain; so a terrain clearance solution would have been required. After changing the position report to input the more accurate; lower; zero fuel weight to attempt to force a M1 solution; and 'prep manning' the EROPS page to input specific M2 airports; still no solution could be generated that provided terrain clearance. The chief dispatcher on duty was called and could not figure it out at first either. Eventually the chief dispatcher was able to generate a M2 solution when the EROPS 'default' button was selected and den was removed from the list of available airports (cos was selected as the M2 airport). The dispatcher then put in release 4 with cos as the M2 alternate and provided the crew with the terrain solution and cos weather and NOTAMS. It should be noted that den was forecasting gusty variable winds; and thus would be considered unsuitable. However; 'ignore suitability' for den was attempted and still did not produce a valid terrain clearance solution.the safety concern here is that the dispatcher was able to plan and release a flight crossing an area that would require [our flight planning software] to generate a M1 or M2 terrain clearance solution with no error generated whatsoever to alert the dispatcher that this had occurred (additionally; a far was unintentionally violated by issuing release 3 with no terrain clearance when it was required). It is conceivable that a M1 or M2 solution would not even be possible in certain circumstances and this would pose a safety risk.

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Original NASA ASRS Text

Title: A Dispatcher described his difficulty manually revising an A320's inflight terrain clearance release over the Rocky Mountains. An engine anti-ice valve had been MEL'ed open and special procedures were required because of the available alternate airports.

Narrative: Flight was operating to the west coast on a manually built route crossing the Rocky Mountains in Colorado. The fight was originally planned and released with a Method 1 (M1) terrain clearance solution. Maintenance deferred an engine anti-ice valve in the open position; so release two was planned and released with MEL 30-21 applied. This new flight plan was planned and released with a Method 2 (M2) solution with DEN and LAX as the listed M2 alternates. Once enroute; weather allowed for a more direct routing; so the dispatcher asked the crew to request direct from their present position (over Nebraska a bit west of the SPAWN waypoint) to the BLD VOR (located in southern Nevada). The crew acknowledged; requested; and was cleared direct to BLD; and informed the dispatcher of that fact. Wishing to compute a new flight plan for this new direct route (in order to get new fuel burn and ensure terrain clearance); the dispatcher requested a FMC position report; which was entered in. The dispatcher then put the new route in and computed a flight plan. The error 'no point-circle crossing found for ZZZ' (or something to that effect) was displayed. To correct this error; the dispatcher went to the EROPS tab and clicked 'default' (the flight had been planned with 'prep man' selected and alternate airports of ZZZ; DEN; and LAX). This altered the EROPS solution to alternate airports of LNK; INW; and LAX; and produced a solution with no errors (other than perhaps the usual 'insufficient fuel' or similar error that is always generated when calculating an airborne flight). The dispatcher then released the flight with the new direct routing.Immediately upon inputting release 3; the dispatcher realized that there was no terrain clearance solution generated. The flight was still east of the Rockies at the time and crossing over areas of high terrain; so a terrain clearance solution would have been required. After changing the position report to input the more accurate; lower; zero fuel weight to attempt to force a M1 solution; and 'prep manning' the EROPS page to input specific M2 airports; still no solution could be generated that provided terrain clearance. The chief dispatcher on duty was called and could not figure it out at first either. Eventually the chief dispatcher was able to generate a M2 solution when the EROPS 'default' button was selected and DEN was removed from the list of available airports (COS was selected as the M2 airport). The dispatcher then put in release 4 with COS as the M2 alternate and provided the crew with the terrain solution and COS weather and NOTAMS. It should be noted that DEN was forecasting gusty variable winds; and thus would be considered unsuitable. However; 'ignore suitability' for DEN was attempted and still did not produce a valid terrain clearance solution.The safety concern here is that the dispatcher was able to plan and release a flight crossing an area that would require [our flight planning software] to generate a M1 or M2 terrain clearance solution with no error generated whatsoever to alert the dispatcher that this had occurred (Additionally; a FAR was unintentionally violated by issuing release 3 with no terrain clearance when it was required). It is conceivable that a M1 or M2 solution would not even be possible in certain circumstances and this would pose a safety risk.

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.