Commercial Fixed Wing
Flight Crew Air Transport Pilot (ATP)
Distraction; Human-Machine Interface; Situational Awareness
Deviation - Altitude Crossing Restriction Not Met; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Became Reoriented
Human Factors; Procedure
ATC cleared us to cross MUNKY Intersection on the POLAR3 arrival into DTW at the expected; planned; and standard FL230. Our altitude was FL270. The Captain and I were talking. MUNKY fix started flashing indicating station passage. I recorded the fuel on the dispatch release. I then realized I had not begun descending. I told the Captain I had forgotten to descend and selected power idle; full spoilers; vertical speed down 3;500 FPM. As I began descending; ATC told us to change to Cleveland Center. We leveled at FL230 5 to 6 miles after MUNKY fix. The threats were the crossing restriction on a quiet morning and the conversation in the flight deck to keep our minds active. My error as the flying pilot was not initiating the descent when assigned by ATC; not perceiving the snow flake or 3 degree guidance in my scan; and the Captain not catching my error in his monitoring cross check. The undesired aircraft state was being 4;000 FT too high above our crossing fix.I should; as I usually do; begin descending immediately when assigned crossing fixes. I should; if planning a 3 degree descent; ask the Captain to remind me if he sees me not acting at the 3 degree descent point. I should be aware that conversation; though good in keeping the mind active; also leads to distraction from flying responsibilities especially during low levels of activity; such as at cruise.
Air Carrier flight crew failed to initiate descent in time to make assigned crossing restriction on the POLAR3 arrival into DTW.