Challenger CL600
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 85; Flight Crew Total 12000; Flight Crew Type 6000
Workload; Training / Qualification; Distraction; Confusion
Deviation - Altitude Excursion From Assigned Altitude; Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Returned To Clearance; Flight Crew Took Evasive Action
Procedure; Human Factors
We were cleared to hold on the 220 radial off of the arrival VOR at 12 miles during arrival. As the First Officer; Pilot Monitoring; was trying to get the hold into the FMS we were cleared to descend to 5000 feet. The altitude alerter was then set to 5000 feet. During the descent; prior to 7000 feet ATC then asked us to stop our descent and maintain 7000 feet. The altitude alerter was not reset to 7000 feet (still set to 5000 feet). This happened because both crew were trying to input the difficult hold instructions into the FMS that was confused by one pilot missing the '12 DME' requirement. The aircraft descended to 6500 feet before the correction was made back to 7000 feet. The Captain; Pilot Flying; was busy trying to assist with inputting the difficult hold clearance (with clearance confusion); and was not watching the aircraft flight path. Simple standard procedures and monitoring broke down while trying to program the FMS when clearance and procedures became confusing.
During a descent to 5;000 feet; ATC issued a complex hold instruction. Then while struggling with the FMC hold entry; ATC modified the altitude to maintain 7;000 feet; but the busy crew failed to level. At 6;500 feet they realized their error and climbed.