Elias W. in front of AS-K 21, serious student
Wind is frontal right to rearward left in photo.
Typical late day lennies
|Mountain Wave - Required Weather
- Wind at Mountaintop at 20 kts or more
- Wind Direction within 45 degrees of perpendicular to ridge
- Wind Smoothly increasing with altitude, no direction change of
more than 30 degrees
- More stable layer at mountaintop level between less stable
layers at the surface and high aloft
|Clouds Associated with Mountain Wave
|Altocumulus Standing Lenticular
How to Find Smooth Area or How to Find Lift Area
- Determine wind aloft direction -- wheres upwind?
- If youre in chop or turbulence, move upwind = closer to
parallel mountain line, to find an area of smooth air.
This may mean shifting parallel as much as a half-mile.
- This should place you in smooth lifting air. If you need to
descend, move downwind of the turbulent area.
How to Cross a
Mountain Line During a Wave Condition
(for airplane drivers primarly, but glider folks, too)
Climb for extra altitude in lift band prior to last mile
headed upwind to the ridge. Be willing to add 2000 or 3000 ft. extra before crossing
upwind, then spend the altitude in extra cruise speed as you pass upwind near the ridge.
Cross at 90 degrees for shortest distance in the strong sinking air. Be willing to turn
Climb for extra altitude (1000-2000 ft) prior to crossing the
mountain. You will find strong sink on the leeward edge (over the waterfall), keep speed
up and sacrifice altitude to continue cruise speed. Watch VSI. When entering lift area
slow up a lot and recover your altitude. Work parallel to mtns. in lift band, climb
OVER rotor and continue downwind.
Tell ATC you are experiencing mountain wave, and you
will not be holding your cruise altitude while transitioning this area. Try to advise them
of your intentions. They are there to serve you.
|Wave Window Information
California City has two separate processes for flying in wave conditions. A
different set of flight rules apply, depending on what the military users of our airspace
If the military users (DoD) are active, then we can only have
access to airspace above FL180 by being a "joint user." This means we will be
equipped with Mode C transponders, or we will operate one transponder glider with one
non-transponder glider as a formation flight of two.This is the process that we use during
Wave Camp, when we are scheduled as users jointly with the military above FL180. Wave Camp
is scheduled for the first two weeks of March inclusive of three weekends. We have been
historically "clean" users here for 10 years, and have updated the letter of
agreement with the military to allow us year-round access as joint users, WITH
TRANSPONDERS above FL 180.
Sunset typical lenticulars (lennies), looking WSW from
For this letter of agreement, the flight area is called Wave
Camp window. It is from California City Airport to Mojave Airport to Tehachapi Pass at Hwy
58 to the north east end of Lone Tree Canyon and return to California City.
When the military is not using, we can have access to larger
different geographic areas with no transponder requirement for above FL180. You must have
the ability for each glider to monitor ATC on 133.65 and comply with all ATC instructions,
including "requests" to descend or cap off climb altitudes. There are three
large glider areas that follow the bands of the Sierras stretching from Cal City to
alongside Inyokern and on north to Lone Pine. These are called Glider One, Two and Three.
There is nothing north of the north edge of Owens MOA.
North of Owens MOA the airspace responsibility shifts to FAA
at Oakland Center. Due to the volume of airline activity around the end of Owens MOA, a
window at Bishop is a very slim possibility, and does not currently exist. Also, Oakland
Center hasn't been happy with PASCO and Minden's lack of effective management of their
windows. Flights outside of windows, or without windows are big threats to the glider
relationship with ATC for the long term, not to mention risks to your personal flight
safety! Don't jeopardize our future privileges.
The no-transponder operations require ATC to separate IFR
(airline) traffic around the lateral boundaries or 2000-ft. over active glider wave
windows. Additionally, there are few days that the Navy, Air Force or Army is NOT using
the R-2508 airspace. (This is what prompted us to ask for "regular" joint use
with transponders on a year-round basis.)