Date: 201509
Local time of day: 1201-1800
Location: TNCM.Airport, FO
Flight conditions: VMC
Light: Daylight
Aircraft: B757 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Descent
ATC / advisory: Center ZSU
Aircraft component: FMS/FMC
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Anomaly: Aircraft Equipment Problem Less Severe; Inflight Event / Encounter Other / Unknown
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Became Reoriented; Flight Crew Overcame Equipment Problem
Contributing factors: Human Factors; Aircraft; Incorrect / Not Installed / Unavailable Part
Primary problem: Incorrect / Not Installed / Unavailable Part

Narrative: Approach Missing from FMC Database: In preparation for landing at SXM/TNCM/St. Maarten Princess Juliana airport; the captain/pilot flying attempted to select the preferred approach in the FMC. The preferred approach per the ATIS is the VOR Z Rwy 10; which allows for a straight-in approach rather than a procedure turn. The other two VOR approaches require a procedure turn; and the 757 aircraft are not qualified to fly the RNV (GPS) Rwy 10 approach. However; for an unknown reason; the VOR Z approach is not included in the latest FMC database. Because this is an approach path (rather than an enroute path); the Boeing 757 FMC requires special logic in the FMC path definition to allow the autopilot to properly fly the approach. For that reason; pilots are not allowed to manually build an approach in the FMC. The only published approaches loaded in the database at present are the VOR X 10 and the VOR Y 10; which each require a procedure turn rather than a straight-in approach; and are therefore undesirable for traffic flow efficiency (they take a long time to fly; during which other aircraft cannot land). Because of the Boeing 757 FMC constraints (which also apply to other aircraft as far as I know); we could only legally fly the desired VOR Z 10 approach using raw data; which is more task-intensive than flying the approach using the FMC; and is not a method we normally practice. As a result; we chose to input the VOR Z 10 approach fixes prior to and including the FAF in the route; and fly a visual approach once we had the airport in sight. This technique was quite safe since the weather was nice; but presumed we would be able to visually acquire the field prior to reaching the FAF.  Had the weather been marginal (which is possible this time of year due to the tropical depressions that form); we would have been forced to either fly the approach in raw data or tie up the traffic pattern for an inordinately long time while we flew one of the two procedure turn approaches.For an unknown reason; effective procedures for including all appropriate approaches in the FMC database were not followed by the individuals that developed the September FMC database release. In addition; this failure was not detected by quality assurance personnel. As a result; a defective database was installed in aircraft flying operational air carrier flights. While we had backup methods that could be used to work around this failure in this case (raw data approach; alternative approaches); this failure should never happen; and the fact that this failure reached operational aircraft indicates the organizations and individuals maintaining the FMC databases have serious quality control shortcomings that need to be corrected. Had there been no other available approach and the weather been bad; at best this would have resulted in an expensive diversion. Had the failure instead been incorrect data rather than a missing approach; a tragic accident could have occurred if the aircrew did not catch the discrepancy.Suggest a review of the procedures used for ensuring appropriate approaches are installed in the FMC database releases; and correct procedural shortcomings that could result in failures. Ensure corrected procedures are followed. Review quality control processes to ensure they trap production errors before they reach operational aircraft.Upon saving this report; I noticed that I previously submitted a report; indicating that the FMC database at that time had NO approaches available; and that the VOR Z Rwy 10 should at least be included. Since that approach is still not available in the FMC database months later; there is clearly a serious problem in the database development department; and this problem deserves high level attention to ensure it is permanently corrected.




Synopsis: B-757 flight crew noticed that the preferred approach was not in the FMC database. The crew flew a visual approach coupled with manually inputted waypoints to the final approach fix.