Date: 201205
Local time of day: 0601-1200
Location: BFI.Airport, WA
Flight conditions: VMC
Light: Daylight
Aircraft: B767-200
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Initial Climb
Airspace: Class D BFI
ATC / advisory: TRACON S46
Aircraft component: FMS/FMC
Component problem: Malfunctioning; Design
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Human-Machine Interface; Confusion
Anomaly: Aircraft Equipment Problem Less Severe; Deviation - Speed All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew FLC Overrode Automation
Contributing factors: Aircraft; Human Factors
Primary problem: Ambiguous

Narrative: We were assigned the 130 degree heading; climb to 2;000 FT MSL on the KENLN5 departure off Runway 13R at BJI. On initial climb the takeoff was normal until I called for 'VNAV; Flaps 5; Speed Clean Maneuver' at 1;000 FT AGL. FMS/Flight Director commanded a descent and a speed reduction then retarded the thrust levers through the autothrottles. I notified the Captain; who commanded; 'Auto throttles off; flight director off; continue the climb raw data.' I complied and maintained the flight path to climb to 2;000 FT on a 130 degree heading. We retracted flaps to zero on profile and accelerated to clean maneuver airspeed; approximately 207 KIAS.Subsequently directed by Seattle Departure to; 'Turn left heading 070; climb to 6;000 FT.' I initiated the turn and climb raw data. Captain was trouble-shooting the FMS. We encountered a couple of audible warnings in trying to re-engage the automation. I became distracted in the turn; dropped my heading scan and turned through 070 degrees. Seattle Departure prompted us and called to assign a new heading of 040 degrees. I turned to 040 degrees; and refocused my scan on climb and heading. Subsequently I did not deviate from assigned clearances; headings; altitudes or airspeeds.The failure to roll out on 070 degree heading as assigned was my fault; because I allowed myself to become distracted in a high workload environment by automation audible warnings/cautions. I think we did a good job of reverting to raw data flying and ensuring a safe initial climb flight path despite bad Flight Director commands. I think I should have focused more and complied with the vector the first time.In later discussing the incident with the Captain; we determined the FMS/CDNUs were properly programmed and cross checked for vertical and lateral navigation. No errant altitude entries were made that would explain why the Flight Directors commanded a descent and speed reduction. I think we were prepared to revert to basic piloting skills; and did a good job of flying while continuing the climb.KENLN5 departure has a history of unreliability for navigation purposes. There was a Flight Crew Letter which stated the Airport Authority did not want crews to use the departure. I think there is an anomaly in this departure which the FMS does not deal with well. Recommend that our flight crews not program the KENLN5 until further notice.




Synopsis: A B-767-200 flight crew; cleared to climb to 2;000 FT MSL on a 130 degree heading after takeoff from BFI; encountered confusing and possibly erroneous pitch and thrust commands from the FMS when transitioning to VNAV and starting to clean up while climbing through 1;000 FT MSL. They transitioned to raw data and manual control of the thrust levers. They believed all pre-event programming of the FMS to have been correctly entered.