Commercial Fixed Wing
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Communication Breakdown
ATC Issue All Types; Deviation - Altitude Crossing Restriction Not Met; Deviation / Discrepancy - Procedural Published Material / Policy
General None Reported / Taken
Human Factors; Procedure
On KORRY 4 Arrival to LGA. Assigned 300+ knots. 10 miles prior to BRAND ATC directed us to slow to 250 knots. After updating the box; it was determined that we were unable to comply with the slow down and still reach KORRY at 10;000'. I; as Pilot Monitoring; was unable to contact ATC to request relief due to radio congestion. Pilot Flying did his best to meet restrictions but was unable due to circumstances. When contacting Approach Control; I notified them that we were unable to meet the restrictions at KORRY. He did not respond to the crossing restrictions at all and gave us a clearance for ILS intercept. ATC needs to be educated about aircraft performance. They are constantly requesting us to do the impossible. We cannot go down and slow down at the same rate or as planned by the FMC. Educating them as to what aircraft can do and how to plan accordingly and to give acceptable clearances would alleviate thousands of reports.
Pilot reported missing a crossing altitude restriction due to high airspeed assigned by ATC.