MajorTurbulence
Line Up and Wait
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- Jan 9, 2013
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MajorTurbulence
In my cross the country trip to Yosemite around September 8, I would prefer to land and depart KMMH Mammoth instead of the no brainer at KBIH Bishop. I’m in a Pa28-181 which is obviously normally aspirated. I recognize that purposefully staying under gross as much as practical( I think I can keep it at least 100lbs under MGW), leaning for best power, leaving early in the AM to keep the daytime temperatures at their lowest will maximize performance. The likely temperature and pressure altitude will place the performance graph (with and without take off flaps) above that given in the POH, so while extrapolation may be risky, I’d estimate 4400ft without and 3600 ft using 25degrees flaps for a no wind departure over a 50ft object.
A review of the available airport information includes the availability of an Instrument approach directed at runway 27 for arrivals, but obstacle clearance is also an issue on departures with a ridge 3 miles from AER 9. The runway has a 1% up gradient to the west. The ODP uses the Nikol 1 departure procedure calling for 500ft/nm climb for Runway 27 and 370ft/nm for Runway 9, which I’m pretty sure exceed the performance available for my Archer at likely density altitudes. My preference however is to do the arrival and departure VFR. I’ve already analyzed my future departure with similar DA issues for KBCE Bryce Canyon, which I think presents fewer terrain issues.
I’d like advice and information from those intimately knowledgeable with Mammoth, and especially those who have gone there in a similar non-turbo single to hear about their experiences and best practices to get in and out, especially with VFR conditions for obstacle clearance. I would hope that performance is adequate to avoid the close by obstacles in the pattern, and that circling overhead the airport could be done to gain additional altitude to transition to the cruise segment. With the nearby terrain, I’d expect turbulence to be a consideration.
A review of the available airport information includes the availability of an Instrument approach directed at runway 27 for arrivals, but obstacle clearance is also an issue on departures with a ridge 3 miles from AER 9. The runway has a 1% up gradient to the west. The ODP uses the Nikol 1 departure procedure calling for 500ft/nm climb for Runway 27 and 370ft/nm for Runway 9, which I’m pretty sure exceed the performance available for my Archer at likely density altitudes. My preference however is to do the arrival and departure VFR. I’ve already analyzed my future departure with similar DA issues for KBCE Bryce Canyon, which I think presents fewer terrain issues.
I’d like advice and information from those intimately knowledgeable with Mammoth, and especially those who have gone there in a similar non-turbo single to hear about their experiences and best practices to get in and out, especially with VFR conditions for obstacle clearance. I would hope that performance is adequate to avoid the close by obstacles in the pattern, and that circling overhead the airport could be done to gain additional altitude to transition to the cruise segment. With the nearby terrain, I’d expect turbulence to be a consideration.
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