Engineers Prove 1,022 NM Engine-Out Range In 180 Minute Time
Cessna announced Monday that Citation Sovereign Part 135
operators will now be able to conduct certain over-water flights,
specifically Los Angeles to Hawaii, without requiring FAA Extended
Operations (ETOPS) approval.
To qualify for the ETOPS exemption, a passenger aircraft flying
with an engine out must never be more than 180 minutes from a
suitable airport. In the case of the Sovereign flying L.A. to
Hawaii, analysis proves the aircraft can fly 1,022 nautical miles,
just over halfway, in less than 180 minutes at the engine-out
"This is a response to customer requests for help in meeting
this profile as L.A. to Honolulu is sure to be a popular route with
Cessna's charter operators," said Roger Whyte, senior vice
president, Sales & Marketing.
Cessna Engineering conducted an analysis using worst case weight
and determined the Model 680 Sovereign is capable of travelling a
distance of 1,022 nm in 180 minutes (under standard conditions in
still air) after an engine failure. This analysis is based on a sea
level takeoff at maximum takeoff weight (30,300 lbs), a direct
climb to 43,000 feet using the Operating Manual multi-engine climb
profile, followed by cruise at maximum cruise thrust. At the engine
failure point (1022 nm into the trip and weight of 26,209 pounds)
the airplane drifts down using the Operating Manual drift down
procedures to the drift down altitude.
After reaching the drift down altitude, the airplane descends at
a rate of 3,000 fpm at a speed of VMO/MMO - 10 knots to 25,000
feet. At 25,000 feet, the aircraft levels and cruises using maximum
continuous thrust until starting the final descent to the diversion
airport. The final descent is flown at a rate of 3,000 fpm and VMO
-10 knots from 25,000 feet to 10,000 feet and then at 250 KIAS at
idle thrust until reducing speed for landing.
This profile will support several of the over-water missions
Sovereign operators desire to fly. The key in planning missions of
this type is to maintain a maximum 1,022 nm or smaller radius from
a suitable landing airport. The operational guidance for this
procedure will be included in the next revision (Revision 8) of the
680 Airplane Flight Manual (AFM) due out in early 2010.