Date: 201202
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: Mixed
Weather elements / visibility: 10
Light: Daylight
Aircraft: Embraer Legacy 600 (EMB135BJ)
Operator: Air Taxi
Operating under: Part 135
Flight plan: IFR
Mission: Passenger
Flight phase: Final Approach
Airspace: Class E ZZZ
ATC / advisory: UNICOM ZZZ
Reporter organization: Air Taxi
Reporter function: Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Instructor; Flight Crew Multiengine
Human factors: Communication Breakdown; Fatigue; Other / Unknown; Situational Awareness
Anomaly: Deviation - Altitude Crossing Restriction Not Met; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Took Evasive Action; Flight Crew Became Reoriented
Contributing factors: Human Factors
Primary problem: Human Factors

Narrative: ATC cleared us for the GPS [approach] and switched us over to the advisory frequency while just outside the final approach fix (which had a platform of 2;000 FT MSL). I had my MFD range display on 25 NM instead of 2.5 NM. Due to fatigue or complacency I did not look at the GPS distance display on my MFD; but instead relied on the picture of the aircraft over the fix to begin my descent. This was a stupid; careless; rookie error. The weather was not bad. I had ground contact and could see all the way to the airport; but I did not have the VASI in sight at the time I started my descent. When I realized my error I was at 1;800 FT MSL and this is when I compounded my mistake. In my haste to correct the situation reached up to hit the ALT mode button to arrest my descent; but wound up pushing the wrong button then attempted to initiate a climb with the VSI knob. It wasn't until I had descended further (to approximately 1;500 FT MSL) that I reached the fix; picked up the VASI; and continued to a normal visual approach. The lack of discipline I displayed in this situation confounds me. I have never done something like this in my entire career. I can't explain why I did not look at the distance readout before starting my descent. It could be that because the conditions were quasi-visual I allowed myself to less vigilant than is customary. There were no charted obstacles; I could see the airport environment; the ground; and a clear flight path between my aircraft and the next cloud layer. These factors combined with a short; minimally legal; overnight rest period conspired against me. It is important that pilots remain alert and stick to procedures even when conditions make them think they won't matter. Take the extra second to look at the display readout. If you have the range on the MFD map set to something you don't expect it could bite you. Also; the pilot not flying should not hesitate to call out a mistake like this; and Captains should make certain their First Officers know to speak up. My pilot not flying did not say anything to me until we were at the fix. 'You are OK to descend now.' I would have appreciated his input sooner.




Synopsis: An EMB135 Captain began his descent early on a GPS approach because of fatigue or complacency; but his First Officer did not correct his error although the Captain had expected him to.