Flight Crew Air Transport Pilot (ATP)
Distraction; Situational Awareness; Time Pressure
Deviation - Altitude Crossing Restriction Not Met; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Object
Flight Crew Returned To Clearance; Flight Crew Became Reoriented
Environment - Non Weather Related
While on the KORRY 3 Arrival into LGA; just passing between BRAND and KORRY intersections we encountered what appeared to be a weather balloon. The balloon appeared to be about 4 to 5 FT in diameter and equally as long; it passed about 50 FT off the nose. I was the pilot not flying and in the process of preparing the aircraft for landing; setting up the landing data and getting the weather information. I heard the Captain yell and saw him duck. It startled me quite a bit as did it him. We had just passed BRAND at 11;000 FT and the next step down is 10;000 FT at KORRY with not a whole lot of time to make the restriction especially at higher speeds which ATC requested. It was so startling that we did not get down to 10;000 FT by KORRY. As soon as I realized we didn't make the restriction I notified ATC and told them the reason why; stating that the balloon had just missed us. The Controller did not seem to be concerned but I thought it was important that he know about the balloon as it was floating on the arrival. We continued to 10;000 FT then the Controller issued us a lower altitude and we continued into LGA with an uneventful landing. Prior to KORRY we had no problems meeting any of the other crossing restrictions on the KORRY 3. As far as avoiding a future recurrence; I don't know that there is much that there is much that can be done about the balloon except that it's a good reminder to always be aware of your surroundings. For the crossing restriction I suggest that you always dial in the next altitude and not 10;000 that way you are aware of your position on the arrival and least don't run the danger of getting too low. This is exactly what we briefed and did and ultimately we both just got distracted; it is certainly the closest I've ever come to another object hitting us while airborne. I would suggest to everyone to remember to fly the airplane no matter what and talk about the problem on the ground unless it requires attention at that exact moment.
An Air Carrier First Officer reported a near miss with what appeared to be a weather balloon at 11;000 FT between BRAND and KORRY Intersections on the LGA KORRY 3 Arrival.