Narrative:

On the FRDMM3 RNAV arrival into reagan national; we were initially cleared direct bucko; cross at FL310. Descent profile was set in the FMS to cross at FL310. A few minutes prior to bucko; ATC cleared us to FL250. The altitude was set but the FL310 restriction was not deleted from the FMS. There was also a thunderstorm right of course with a significant amount of blow off towards the arrival corridor which caused a great deal of discussion between the captain and myself about deviating left of course. The aircraft leveled at FL310 and was about to begin its programmed descent when center radioed and said that he cleared us to FL250. I hadn't noticed that the captain didn't continue the descent because reagan had switched from south to north operations and I was heads down updating both the ATIS and the route in the FMS. He immediately began a descent to FL250. I asked for a deviation left of course due to the weather and was given approval for a left deviation with direct pldge when able. As we were leveling off at FL250; center cleared us to descend via the FRDMM3. The captain never got the aircraft back into VNAV pth which was programmed for the altitudes on the FRDMM3 arrival. He was focused on the weather and started the descent a little late and shallower than required to meet the crossing restriction at pldge. I was distracted by several flight attendant calls to the flight deck and when I realized the captain's descent was too shallow to make the pldge altitudes I immediately informed him that he needed to get down in a hurry. He eventually got the aircraft in a significant descent with speed brakes but it was evident we would not make the pldge altitudes. Center switched us to potomac approach and I checked in and notified them that we were done deviating and that we were at 19;000 in the descent over pldge and that we were doing are best to get down. Approach notified us to get back on the arrival altitudes a soon as possible. I feel several areas were factors in leading up to the missed altitude. The two biggest issues were distraction and overreliance on automation for RNAV arrivals. The weather; runway change; updated ATIS; and flight attendant calls lead both the captain and I to be distracted with the weather deviation; as well as required FMS changes. I also think that; when flown as planned; RNAV arrivals (even complex ones like FRDMM3) are effectively managed by the FMS and autopilot. When ATC requests that they are not flown as published or you must deviate from the course it becomes more difficult to manage arrivals with a great deal of mandatory altitudes in close proximity. I also feel that my inexperience in type; as well as being my first time into reagan national; was also an issue. The boeing FMS handles descents significantly different than previous aircraft I have flown and my inexperience resulted in a late recognition of the necessary descent to make the altitude. I think the best way of preventing a recurrence is through education for pilots and ATC on the challenges that occur when an aircraft has to deviate on RNAV arrivals with a multitude of step down altitudes.

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Original NASA ASRS Text

Title: B737 First Officer reported being distracted during the FRDMM3 Arrival to DCA with the Captain flying. Distractions included Flight Attendant calls; weather deviations; a runway change and ATC adjustments to the arrival; and resulted in PLGDE being crossed above 17000 feet.

Narrative: On the FRDMM3 RNAV arrival into Reagan National; we were initially cleared direct BUCKO; cross at FL310. Descent profile was set in the FMS to cross at FL310. A few minutes prior to BUCKO; ATC cleared us to FL250. The altitude was set but the FL310 restriction was not deleted from the FMS. There was also a thunderstorm right of course with a significant amount of blow off towards the arrival corridor which caused a great deal of discussion between the Captain and myself about deviating left of course. The aircraft leveled at FL310 and was about to begin its programmed descent when center radioed and said that he cleared us to FL250. I hadn't noticed that the Captain didn't continue the descent because Reagan had switched from South to North operations and I was heads down updating both the ATIS and the route in the FMS. He immediately began a descent to FL250. I asked for a deviation left of course due to the weather and was given approval for a left deviation with direct PLDGE when able. As we were leveling off at FL250; center cleared us to descend via the FRDMM3. The Captain never got the aircraft back into VNAV PTH which was programmed for the altitudes on the FRDMM3 arrival. He was focused on the weather and started the descent a little late and shallower than required to meet the crossing restriction at PLDGE. I was distracted by several FA calls to the flight deck and when I realized the Captain's descent was too shallow to make the PLDGE altitudes I immediately informed him that he needed to get down in a hurry. He eventually got the aircraft in a significant descent with speed brakes but it was evident we would not make the PLDGE altitudes. Center switched us to Potomac approach and I checked in and notified them that we were done deviating and that we were at 19;000 in the descent over PLDGE and that we were doing are best to get down. Approach notified us to get back on the arrival altitudes a soon as possible. I feel several areas were factors in leading up to the missed altitude. The two biggest issues were distraction and overreliance on automation for RNAV arrivals. The weather; runway change; updated ATIS; and FA calls lead both the Captain and I to be distracted with the weather deviation; as well as required FMS changes. I also think that; when flown as planned; RNAV arrivals (even complex ones like FRDMM3) are effectively managed by the FMS and autopilot. When ATC requests that they are not flown as published or you must deviate from the course it becomes more difficult to manage arrivals with a great deal of mandatory altitudes in close proximity. I also feel that my inexperience in type; as well as being my first time into Reagan National; was also an issue. The Boeing FMS handles descents significantly different than previous aircraft I have flown and my inexperience resulted in a late recognition of the necessary descent to make the altitude. I think the best way of preventing a recurrence is through education for pilots and ATC on the challenges that occur when an aircraft has to deviate on RNAV arrivals with a multitude of step down altitudes.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.