Narrative:

This aircraft was operating under an MEL deferral for an inoperative FMS. Maintenance had been performed the night prior to update the FMS nav database; but the installation had failed resulting in a corrupted database. The result was the FMS was not merely out-of-date; but it rendered the entire FMS unusable. The restrictions associated with this MEL were noted by the crew. We accepted this flight knowing that we would have greater workload but we were comfortable with this. After all; terrestrial VOR airways have been the standard means of navigation in the us for over 50 years. However; this flight proved to be much more difficult than I anticipated. It should be noted that in my 16 years of flying corporate jets I have never operated; nor received training in; a jet aircraft using only VOR navigation with inoperative long-range navigation in the enroute airway environment. Initially; the flight was normal but once in washinton center airspace; each controller tried to issue us the paats 2 RNAV arrival. Each time we declined and explained we were not RNAV equipped. This created confusion with the controllers; since the strip did not indicate this and each controller may not have passed the information along to the next. We received numerous vectors and reroutes; some we could not accept and some that we could. At one point; we were given direct hpw; direct pxt; dupont 5 arrival. By the time we got the frequency and bearing established to hpw; we started to determine the next freq and bearing to pxt but had some difficulty determining our position along our route. By the time we fixed our position; we were well past hpw and were late in turning toward pxt. We turned back to the west to re-intercept and ATC inquired where we were going. I got on the radio and confessed that we had missed the turn and were returning to course. The controller then gave us a vector and no more was said about the error. While that was the only nav deviation we had (that I know of); there were many opportunities for problems on this flight. We were in busy airspace (washington center and phl approach) and were repeatedly given clearances we could not fly. There was much confusion by the controllers as to just what we could do. As an example; at one point we were given the paats 2 arrival for the 3rd time; which we declined; explaining that we were non-RNAV (again). We were then given vectors; followed by direct eno; which we accepted. We were then assigned; 'direct hogey; resume dupont 5 arrival.' we had to decline again; explaining that we had no RNAV; and could not go direct to an intersection. To which the controller responded; 'why not? It's not an RNAV arrival?' we then had to explain that we could not navigate directly to an intersection unless given vectors to a radial that defines the intersection. This was not an angry exchange at all; but involved a lot of chatter and air-time on a busy frequency. Almost every aspect of the flight was encumbered with much higher workload. It should be noted that with a blank FMS screen; one also has a blank mfd screen. No moving map; no instant situational awareness. Flying on a vector off-airway; in IMC; with no easy reference to position relative to the last or expected route. Referencing enroute charts on the ipad; which requires extensive 'drill-down' to find VOR freqs; radials; or airway courses. Calculating descent points for crossing restrictions; calculating landing weights and fuel remaining at destination; etc; all drawing upon skills and techniques long unused and never trained any more. Even finding the airport from a vector to a visual approach was difficult; since we could not just glance down at the mfd for reference. No distance and bearing to the airport; no extended centerline. At almost any given moment; it seemed we were both 'heads-down;' just to keep some idea of where we were and what we were doing next. Aircraft monitoring was at times severely compromised due to the increased workload; but I am happy to report that we were lucky and we had no excursions other than the nav deviation noted. 1) this MEL is good for 10 days; but clearly this is not an acceptable practice for a company as safety focused as we are. We were ferrying to fly passengers that day; but we should have been going directly to maintenance. Make this a 3-day MEL; with great emphasis on flying only 1 flight directly to maintenance. 2) any flights with all FMS deferred should require acp approval prior to dispatch. The acp should review the weather; airports involved; and especially the airspace environment; schedule; and number of legs scheduled until maintenance will be performed. He should then be required to discuss with the PIC before approving the flight. 3) the safety committee; simply put; must work out whatever problems exist with our dispatch department and/or ATC and their procedures for equipment coding on flight plans. Much of the problems we encountered were because ATC did not know of our restrictions.

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Original NASA ASRS Text

Title: CE-560 flight crew discovers that they have become FMC dependent when they are dispatched with an inoperative FMS and are required to navigate using VOR's.

Narrative: This aircraft was operating under an MEL deferral for an inoperative FMS. Maintenance had been performed the night prior to update the FMS nav database; but the installation had failed resulting in a corrupted database. The result was the FMS was not merely out-of-date; but it rendered the entire FMS unusable. The restrictions associated with this MEL were noted by the crew. We accepted this flight knowing that we would have greater workload but we were comfortable with this. After all; terrestrial VOR airways have been the standard means of navigation in the US for over 50 years. However; this flight proved to be much more difficult than I anticipated. It should be noted that in my 16 years of flying corporate jets I have never operated; nor received training in; a jet aircraft using only VOR navigation with inoperative long-range navigation in the enroute airway environment. Initially; the flight was normal but once in Washinton Center airspace; each controller tried to issue us the PAATS 2 RNAV arrival. Each time we declined and explained we were not RNAV equipped. This created confusion with the controllers; since the strip did not indicate this and each controller may not have passed the information along to the next. We received numerous vectors and reroutes; some we could not accept and some that we could. At one point; we were given direct HPW; direct PXT; DUPONT 5 arrival. By the time we got the frequency and bearing established to HPW; we started to determine the next freq and bearing to PXT but had some difficulty determining our position along our route. By the time we fixed our position; we were well past HPW and were late in turning toward PXT. We turned back to the west to re-intercept and ATC inquired where we were going. I got on the radio and confessed that we had missed the turn and were returning to course. The Controller then gave us a vector and no more was said about the error. While that was the only nav deviation we had (that I know of); there were many opportunities for problems on this flight. We were in busy airspace (Washington Center and PHL Approach) and were repeatedly given clearances we could not fly. There was much confusion by the controllers as to just what we COULD do. As an example; at one point we were given the PAATS 2 arrival for the 3rd time; which we declined; explaining that we were non-RNAV (again). We were then given vectors; followed by direct ENO; which we accepted. We were then assigned; 'Direct HOGEY; resume DUPONT 5 arrival.' We had to decline again; explaining that we had no RNAV; and could not go direct to an intersection. To which the Controller responded; 'Why not? It's not an RNAV arrival?' We then had to explain that we could not navigate directly to an intersection unless given vectors to a radial that defines the intersection. This was not an angry exchange at all; but involved a lot of chatter and air-time on a busy frequency. Almost every aspect of the flight was encumbered with much higher workload. It should be noted that with a blank FMS screen; one also has a blank MFD screen. No moving map; no instant situational awareness. Flying on a vector off-airway; in IMC; with no easy reference to position relative to the last or expected route. Referencing enroute charts on the IPAD; which requires extensive 'drill-down' to find VOR freqs; radials; or airway courses. Calculating descent points for crossing restrictions; calculating landing weights and fuel remaining at destination; etc; all drawing upon skills and techniques long unused and never trained any more. Even finding the airport from a vector to a visual approach was difficult; since we could not just glance down at the MFD for reference. No distance and bearing to the airport; no extended centerline. At almost any given moment; it seemed we were both 'heads-down;' just to keep some idea of where we were and what we were doing next. Aircraft monitoring was at times severely compromised due to the increased workload; but I am happy to report that we were lucky and we had no excursions other than the nav deviation noted. 1) This MEL is good for 10 days; but clearly this is not an acceptable practice for a company as safety focused as we are. We were ferrying to fly passengers that day; but we should have been going directly to maintenance. Make this a 3-day MEL; with great emphasis on flying only 1 flight directly to maintenance. 2) Any flights with all FMS deferred should require ACP approval PRIOR to dispatch. The ACP should review the weather; airports involved; and especially the airspace environment; schedule; and number of legs scheduled until maintenance will be performed. He should then be required to discuss with the PIC before approving the flight. 3) The safety committee; simply put; must work out whatever problems exist with our dispatch department and/or ATC and their procedures for equipment coding on flight plans. Much of the problems we encountered were because ATC did not know of our restrictions.

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.