B737-300
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 101; Flight Crew Type 8500
Situational Awareness
No Specific Anomaly Occurred All Types
Flight Crew FLC complied w / Automation / Advisory
Chart Or Publication
On the JAGGR ONE RNAV Arrival into DEN; the chart shows the requirement to cross LYNKN at 280 KTS at or above FL270. We were cruising at FL340 and our top of descent point was past LYNKN. To cross LYNKN at 280 KTS would require flying fairly close to the barber pole speed at FL340; well above our profile speed at FL340 of something close to .74 Mach. The only other way to actually cross LYNKN at 280 KTS would be to initiate a very early descent and even then I don't know how often a given combination of Mach # and transition to 280 would have the aircraft still flying a Mach # at LYNKN at FL270 and slower than the stated 280 KTS.We ended up flying the arrival using the VNAV profile and a transition speed of 280 KTS; which we transitioned to during our descent (i.e. well past LYNKN). ATC said nothing; as we were on a normal speed profile. (We did not accelerate early to an extremely high Mach number in order to be at 280 KIAS at LYNKN nor did we descend early.)This looks to me like a design problem with the arrival. As long as later waypoints have the 280-KT mandatory speed then a properly programmed FMC will fly a constant speed profile; without the issue of forcing Crews to either (a) descend early; (b) fly an extremely high Mach number; or (c) fail to comply with the stated 'at 280-KT' restriction at LYNKN.
A B737-300 Captain believes the crossing restriction of 'At or Above FL270/280KTS' at LYNKN on the JAGGR RNAV STAR to DEN is unrealistic for his aircraft and would require a barber pole descent from their cruise altitude (FL340) or a very early TOD.