Date: 201508
Local time of day: 0601-1200
Location: SNA.Airport, CA
Flight conditions: VMC
Weather elements / visibility: Cloudy; 10
Light: Daylight
Aircraft: Light Transport; Low Wing; 2 Turbojet Eng
Operator: Air Taxi
Operating under: Part 135
Flight plan: IFR
Mission: Passenger
Flight phase: Descent
Airspace: Class A ZLA; Class E SCT
ATC / advisory: TRACON SCT
Reporter organization: Air Taxi
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Flight Instructor; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human factors: Confusion; Communication Breakdown; Human-Machine Interface; Situational Awareness; Workload
Anomaly: Deviation - Altitude Undershoot; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented; Flight Crew FLC Overrode Automation; Flight Crew Returned To Clearance
Contributing factors: Company Policy; Human Factors
Primary problem: Human Factors

Narrative: We are both Captains in our aircraft and each have our own operational nuances regarding technology. Our normal operating procedure is to fly with our dual; Universal FMSs isolated. Each pilot revises his own FPs; STARs; SIDs; etc.; as long as the PF (which is always whomever is in the left seat) has the autopilot engaged. We do this for four reasons: 1) so the PF is always in command of where the airplane is flying; 2) so the PF retains situational awareness of any changes he may input to his FMS; and 3) so the PNF (right seat) can input expected revisions to the FP or to understand how changes could affect flight times/wx decisions; and 4) so FMS 2 can be referenced as a backup should anything fail on FMS 1. Descending into KSNA via the KAYOH5 STAR; I (PF) dialed the ILS20R frequency into the standby frequency of my NAV and had planned to switch it and my NAV source to NAV once SOCAL put me on vectors for the final approach course. This is my normal operating procedure. The PNF asked if I wanted him to switch the ILS 20R frequency into the active side and I said; 'no;' because that's not how I fly arrivals and approaches. However; he then asked if I wanted him to load the ILS 20R approach into the #1 FMS (my FMS). This is his normal process and for some reason I said; 'sure;' thinking I would revise my normal operating process and monitor the switchover on the FMS. Immediately after; on the STAR inside HEC; level at FL180 with the VNAV set and armed; SOCAL revised our routing to the KEFFR3 STAR to 'descend via the STAR.' THE PNF had just finished loading the approach so he immediately reached for my FMS and set about loading the new arrival; which he said he was going to do. It was not a question. Although his doing so was contrary to our normal operating process (I was on autopilot and this would normally be my function since our FMSs were isolated) again I said; 'sure.' What's most important though is that he then went DTO the first fix on the revised routing (on my FMS). I don't recall that we talked about this action; however; it's possible he just said he was going to 'go direct' as he was doing it. I immediately lost my VNAV; the first fix (LUCER) appeared on my PFD; and the airplane began a turn. I was surprised. I asked what was going on because it disrupted my PIC expectations and responsibilities. The action of the PNF going DTO on my FMS while I was in autopilot mode was for him to essentially 'fly' the plane. I was situationally unaware at that moment because the FMS actions took place before either one of us briefed the revised STAR; and was the reason I did not recognize LUCER. I immediately placed the autopilot in HDG mode and looked over at his FMS to determine where SHOULD we be going because I had not expected a turn and I hadn't taken any action to NAV the revised STAR - when each of us independently ensures our current FP routing is in our respective FMSs; it allows us to refer to the PNF FMS should anything disrupt the PF's FMS; it serves as a backup and is the reason I referenced it. In this case; however; his FMS did not match mine because he was inputting changes to my FMS; not his. This further added to my situational confusion. The PNF was also confused; asking what happened to our VNAV. Almost immediately ATC asked us if we were going to start down; which I did; aware that we were above any minimum altitudes for that area. During this brief time; we also passed LUCER. I grabbed the arrival procedure to 'catch up' on the arrival and asked the PNF to give me DTO the next fix on the arrival as it was displayed in the #1 FMS. He gave me DTO LUCER; it was behind us. He gave me DTO RESOR; it was behind us. He gave me DTO BASRE; it was behind us - these fixes are only 8; and 7 miles apart. I was slowing from about 350 KTS indicated and they passed quickly. I was still in HDG mode and actually on course as indicated on the PFD - although each of the STAR fixes indicated behind me as we were ca p with our DTOs. ATC then gave us a vector and descended us. Still situationally behind; I switched to NAV mode once on vectors and set the final approach course. Seeing that we were very near to intercept; I pulled power back; deployed speed brakes; slowed to below 200 KTS; and called for slats. ATC gave us another heading; cleared us to intercept; maintain 3;000 until established; cleared for the approach. We acknowledged. I reset the HDG bug; set APP mode; refocused on my airspeed. Below 190; flaps 20. Air brakes stowed. Looking at my course again; I noticed that APP mode did not arm or engage. I turned off the autopilot and hand flew as we slightly went through final. Gear down; slightly above GS; flaps full; on slope on LOC.         After we landed; I said we'd debrief at the FBO as the PNF said that he was 2 or 3 airplanes behind the sequence. During our debrief; the PNF reviewed all the tactical things we could have done differently to ensure we didn't lose situational awareness. They were good comments. I; however; thought the root cause was that I abrogated my duties as PIC regarding course management and situational awareness to the PNF. This also contributed to the PNF's confusion because it took him out of his Pilot Monitoring (PNF) role. In this case; lack of clear direction from the PF resulted in role confusion and loss of focus on the separate responsibilities of each role. This in turn; set us up for the entire sequence of; 'being behind 2 or 3 airplanes.'




Synopsis: Two captains flying together; each with their 'own operational nuances regarding technology;' created confusion for each other on the KEFFR3 STAR to SNA Runway 20R.