TFE731 Summer 2002

• Fan Disk Replacement Service Bulletin Reminder
• New Authorizations
• Proper N1 DEEC Operation?
• Honeywell N1 DEEC for Citation VII

Fan Disk Replacement Service Bulletin Reminder

— Jon Dodson

The deadline for compliance with Service Bulletin TFE731-A72- 3668 is December 31, 2002 To preclude a possible bottleneck at the end of the year with too many fan disk replacements and not enough service centers to handle them, Honeywell suggests replacing the fan disk when the aircraft is down for scheduled maintenance, or at the operator's convenience. If you have questions or need to schedule your engines, please contact Jon Dodson, Mike Healzer, or Doug Alleman at 800.228.4277.

New Authorizations

— Gerry Riffle

Our turbine engine service center in Lincoln, Nebraska, was recently issued approval and the authorization from Honeywell to perform major periodic inspections on TFE731 20/40/60 engines. This authorization completes Duncan Aviation TFE731 capabilities.

Duncan Aviation has authorization for all of the following engine models: Honeywell's TFE731, TPE331, ATF3 & CFE738, GE's CF34, CF700 & CJ610, Pratt and Whitney's PT6, JT15D & PW305, and Williams Roll's FJ44.

Proper N1 DEEC Operation?

— Craig Bohling

A concern of some pilots has been that the N1 DEEC will not achieve or will overshoot the N1 of the day or the ITT overshoots. Since the N1 and ITT limiters are not externally adjustable, this creates the question, is the N1 DEEC operating properly? In some instances the N1 DEEC had calculated a more accurate N1 than the pilot did. Several factors that may influence this are unapproved takeoff charts, inaccurate altitude and OAT readings used by the pilot in determining N1. Also consider that N1 DEECs were designed to overshoot N1 by .25% to .75% to ensure takeoff N1. Another concern is that N1 DEEC allows the ITT to overshoot. The ITT limiter function is the same as with previous controls and will not start to reduce fuel until the ITT limit has been exceeded. A momentary overshoot will result until the N1 DEEC senses the overshoot, gains control and reduces fuel to the engine. Rapid throttle movement may influence this also. Remember, it is still the responsibility of the pilot to ensure limits are not exceeded.

If you have any questions concerning N1 DEECs please contact Craig Bohling at 402.479.4246.

Honeywell N1 DEEC for Citation VII

— Doug Alleman and Honeywell’s Steve Kersh

Honeywell has begun work on its N1 Digital Electronic Engine Control (N1 DEEC) for the Cessna Citation VII aircraft and expects to receive certification approval by September 2002.

The N1 DEEC reduces pilot workload with improved power management and engine temperature limiting. Control trimming has been eliminated, and the added diagnostic capabilities significantly reduce maintenance labor costs.

Honeywell’s N1 DEEC is easily installed on an aircraft in the same location as the existing electronic engine control with no wiring harness changes.

Aircraft equipped with TFE731 engines that are covered by a Honeywell Maintenance Service Plan (MSP) will be fitted with the N1 DEEC at no charge, at the time of a Core Zone Inspection (CZI) or when existing controls require removal or replacement. Honeywell is offering N1 DEECs to non- MSP customers at a special exchange price for the current control.

The Honeywell N1 DEEC was previously certified for the following applications: Lear 31, Lear 35/36, Falcon 10, Falcon 50, Falcon 20B, Falcon 900B/C, Hawker 400, Hawker 700, Hawker 800 and 800XP.

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