B757-200
Flight Crew Air Transport Pilot (ATP)
Situational Awareness; Distraction
Aircraft Equipment Problem Less Severe; Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Became Reoriented; Flight Crew Overcame Equipment Problem; Flight Crew Returned To Clearance
Aircraft; Human Factors
Right Engine Pressure Ratio with auto throttles MEL. At 1;500 feet AGL [I] called for VNAV and it [would] not engage. Directed the FO to troubleshoot the situation. At 3;000 we cleaned [up] the airplane and performed the after takeoff checklist; while getting vectors from departure with new altitude assignment. I was hand flying the airplane. VNAV still would not engage; directed the FO to engage FLTCH and both tiles then engaged (green). FO tried to disengage the VNAV mode; and it would not disengage. We leveled off at 14;000 with an overshoot of 200 feet; then finally at 14;000. I started to trouble shoot the situation. No EICAS. No status messages; no guidance on the QRH; even though we looked at it to see if we can find something. I was able to get the ALT hold mode and HDG to work; after disconnecting the flight directors; then connected the autopilot. However; I forgot to pull the power back. We had a red indication on the EGT (Exhaust Gas Temperature). FO called the anomaly; I pulled the power back on both engines; and condition was corrected. The engine over temp for less than 30 seconds before it was discovered. We continue to [destination] trying to troubleshoot the VNAV issue. We never got VNAV to work or FLTCH. Lowest level of automation was utilized; and I hand flew the airplane on descent and approach.
The malfunctioning VNAV started a chain of events that ended in us not properly managing the aircraft.
B757-200 flight crew reported they overshot a cleared altitude and exceeded temperature limitations on an engine while they were distracted by a VNAV issue.