B747 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Situational Awareness; Human-Machine Interface; Confusion; Communication Breakdown
ATC Issue All Types
Human Factors; Procedure; Aircraft; Chart Or Publication
ATC's frequent modification of the GIBBZ ONE RNAV ARRIVAL; HVQ transition is flawed. When using the HVQ transition there is a crossing restriction at PHOOW of FL270 then; just 5.7 NM later there is an at or above constraint at HESEE of FL240 or above. The problem is that controllers are issuing HESEE as a hard crossing altitude of FL240. There is NO WAY [to descend three thousand feet in less than six miles; especially at 280 KTS]. Either someone needs to talk to ZDC and inform them or the altitude at PHOOW needs to be lower. Throughout the approach ATC was issuing us altitudes then clearing us to descend via the arrival and not a single altitude was attainable with speed brakes fully extended.
A B747 Captain complained that ZDC is frequently modifying the constraints of the GIBBZ RNAV STAR in ways that make it impossible to comply; specifically changing the 'At or above FL240' at HESEE to a hard crossing just 5.7 NM beyond a previous hard crossing of FL270 at PHOOW.