Oil tank cap and vent
Here is an NTSB official report on the crash of an Exec
90 that you may find can save your ship from crashing:
The private pilot stated during a telephonic interview that he was
hovering in an open field adjacent to the airport, when he began
to lose rotor RPM. He landed briefly to investigate why the helicopter
was not flying properly. He then decided to hover taxi back to his
hangar and was trying to keep the nose of the helicopter pointed
into the wind. While hovering with a slight right crab over a freshly
plowed field the helicopter settled, the right skid contacted the
soft terrain, and rolled onto the right side. The pilot stated that
the loss of rotor RPM was the result of the loose engine
oil cap that sprayed engine oil on the main rotor system drive belts.
The helicopter main rotor blades, tail rotor
blades, fuselage, and tail boom were substantially damaged. There
was no post-crash fire and the pilot reported no injuries. Weather
was reported at the time as winds from 020 degrees at 7 knots, visibility
30 miles with few clouds at 7,000 feet and a temperature of 72 degrees.
When you notice that you are getting oil mist or
an oily film inside of your engine compartment it may be coming
from the oil tank cap. When this occurs you may wish to modify your
system by venting the engines breather overboard away from the engine
compartment. This can be accomplished relatively simply.
- You can fabricate or purchase a vented
oil cap and hose to carry oil mist overboard and out of
Andrew Burr is now
manufacturing a beautiful oil tank cap/vapor vent/ dip stick
combination as seen above.
To check the oil
during your pre-flight you need only to unscrew the dip stick
and check your oil level. No need to remove the cap itself
until you are ready to add oil.
The photo above
shows how Andrew has installed double "O" rings
to seal the oil tank tube so that all oil vapors will vent
out of the overboard vent hose keeping your engine compartment
and belts clean.
Make sure that any vent
cap that you install seals snugly inside of the tank vent
tube or oil mist will sneak by and still make a mess.
You can order one of the
Andrew's new oil caps by sending Andrew an email. Just CLICK