Date: 201808
Local time of day: 1201-1800
Location: CZYZ.ARTCC, ON
Flight conditions: VMC
Light: Daylight
Aircraft: Large Transport
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Descent
ATC / advisory: Center CZYZ
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Flight Instructor; Flight Crew Flight Engineer; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human factors: Situational Awareness
Anomaly: Deviation - Altitude Crossing Restriction Not Met; Deviation - Altitude Undershoot; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Became Reoriented
Contributing factors: Human Factors
Primary problem: Human Factors

Narrative: I was the PM (pilot monitoring). During cruise at FL390 approximately one hour prior to landing I was beginning to check NOTAMs and familiarize myself with the STAR; approach; and company pages. We received an unexpected crossing restriction to descend to FL270 and be level by TULEG. The PF (pilot flying) put FL270 on the legs page at TULEG and executed. I was on the progress page waiting for the new T/D (Top of Descent) point to show up when I noticed the PF having trouble finding the DES NOW prompt. I offered that the FMS had not yet finished calculating the VNAV path for FL270 at TULEG. The PF selected V/S (Vertical Speed) 1000 fpm to begin the descent while waiting for the FMS to finish calculating the new path. We were almost passing FL380 when the FMS finished its calculations; but the DES NOW was still elusive. I suggested re-cruising for FL380; and with this; as we passed FL380 we got the DES NOW prompt. The PF executed that; selected VNAV; and VNAV began a 1;000 fpm descent with the VNAV PTH deviation showing below the path. I called up the VSD on my side and noted the pointer was slightly high. I attributed that to not yet reaching the idle descent path.At this point passing FL370 for FL270 I should have said out loud that we should be about 30nm from TULEG. Had I done that we would not have had an altitude deviation. I was overconfident with VNAV because we had the crossing restriction programmed properly; we got the DES NOW prompt and executed that properly; VNAV was selected; and we had the VNAV PTH deviation indicator showing we were below the path; meaning we had not yet reached the VNAV idle descent path.I went back to reviewing arrival information for the destination...a critical mistake. I should have watched VNAV until we were on the idle descent path. We were still doing 1;000 fpm in VNAV when our mistake became evident. Idle/boards/LVL CHG could not salvage our error. Also; I could not break in on the frequency to advise ATC we would miss the crossing restriction due to frequency congestion.We checked in with the next controller after passing TULEG and level at FL270. He did not mention anything about our TULEG crossing; but the previous controller did ask if we understood cross TULEG at FL270.




Synopsis: Large transport aircraft Captain reported missing a crossing restriction.