Mod Also Ups In-Ground-Effect Hover

Operators of Bell Helicopter's 407 can use a new supplemental type certificate to increase the hot-and-high performance of that light, single-engine helicopter. Bell said this week at Heli-Expo 2010 it has gained approval of Supplemental Type Certificate (STC) No. SR095531RC-D, which allows an increase of the 407's useful load by more than 400 pounds. Alternately, it may be used to increase the 407's in-ground-effect hover by about 3,000 feet. Those gains come with no loss of operational safety margin.

File Photo

The STC will be available through Bell affiliate Aeronautical Accessories, Inc.

The STC draws on excess power available from the 407's Rolls-Royce 250-C47B engine to support revisions of the 407's performance charts for in-ground-effect and out-of-ground-effect hover. Specifically, it uses available power for up to 10 percent above minimum-specification engines for outside air temperatures up to 51.7 degrees C (125 degrees F).

The performance boost requires no hardware or software changes to the aircraft or its engine. It also results in no change to time between overhaul or warranty costs because no engine limits are changed.

The STC includes a Flight Manual Supplement (FMS-8) and an instrument panel placard explaining that the 407's generator load must be reduced below 50 amps to use the revised hover performance charts. A 407's typical generator load is 30 amps.

FMI: www.bellhelicopter.com