Commercial Fixed Wing
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 120; Flight Crew Type 17500
Human-Machine Interface; Situational Awareness; Troubleshooting
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Became Reoriented
Aircraft; Chart Or Publication; Software and Automation
This safety concern occurred on two flights. Same aircraft and same exact routing and runways for departure (7L) and arrival (24R). The routing was the 7L.KEENS2.MESSI ESTWD.HLYWD1.24R. The First Officer briefed all of the points; speeds; and altitudes on the SID via the FMC CDU and I confirmed them on my EFB. We completed the Before Start Origination checklist; received performance takeoff data; and completed the Before Push checklist with no issues. After pushback and engine start; we started to taxi away and when I placed the LEGS Page up on my CDU there was now a discontinuity after the first departure point; and the next point. We corrected the situation by re-selecting the SID; transition; and departure Runway 7L; which removed the discontinuity. That situation by itself would be a little unusual; but as we flew back later on and the same issue occurred yet again it appears that there is a performance software issue that needs to be looked at. The Cost Index was 15 on Flight X and 5 on Flight Y. I unfortunately did not reference the FMC software version. We had no discontinuity on our flight; so the issue could be departure related; the SID related; or performance software related. Bottom line is that there is an issue that might cause pilots to take off and soon afterward encounter a discontinuity on the route; causing a potential navigation error.Flight Ops needs to work with Dispatch and Maintenance to determine if certain weights; Cost Indexes; FMC software versions; SIDS; airports; etc; are causing a discontinuity after receiving performance takeoff data in this fleet or solely this particular aircraft.
Air Carrier Captain reported a discontinuity on the FMC legs page; on the same route; in the same place; two consecutive times.