# Operating Information Letter Honeywell International 1944 E. Sky Harbor Circle Phoenix, AZ 85034

1 of 3 

### OI331-18R4 May 26, 2009 PLEASE DISTRIBUTE TO ALL AFFECT ED FLIGHT CREW MEMBERS AND

MAINTENANCE PERSONNEL

TO: All Owners/Operators, Airframe Manufacturers, Distributors, Sales and Service Organizations, and Field Service Representatives

APPLICATIONS: All TPE331 Series Engines e quipped with Woodward Fuel Control Units, except TPE331-14/15 series engines.

PURPOSE: The purpose of this OIL is to inform operators of single-engine aircraft only , of the probable engine responses following a loss of drive between the engine driv en fuel pump and fuel control

governor system. This OIL does not apply to multi-engine

aircraft

. Reference OI331-12R6 for multi-engine operation

.

WARNING

This OIL is intended to inform the ope rator of the probable engine responses following a loss of drive between the engi ne driven fuel pump and fuel control governor system. Subsequent handling of the engine and control of the aircraft must be performed/maintained pe r the aircraft’s Pilot Operating Handbook (POH), Aircraft Flight Manual (AF M) or Manufacturer’s Operating Manual (MOM), whichever is appropriate.

DISCUSSION

Engine response following a loss of drive between the engine driven fuel pump and the fuel control governor system is dependent on the phase of opera tion (ground engine start, ground or flight operations) and whether the fuel control is in compliance with one of three engine model specific bulletins (TPE331-A73-0254, TPE331-A73-0262 and TPE331-A73-0271) . If the fuel control installed on the engine is not in compliance with one of the applic able service bulletins, a loss of drive between the engine driven fuel pump and fuel control governo r system will result in a condition where the fuel control underspeed governor will increase fuel flow along the acceleration schedule until reaching the maximum fuel flow stop setting. The fuel flow increase will result in a rapid, uncommanded, uncontrolled increase in fuel fl ow to the engine. Service Bu lletins TPE331-A73-0254, TPE331-A73- 0262 and TPE331-A73-0271 implement an improved overspeed governor mechanism in the fuel control assembly that will limit fuel flow if loss of drive occurs between the fuel pump and the fuel control assembly. Fuel flow in the modified controls is limited to approximately 180 pph, whichHoneywell International 

# Operating Information Letter 1944 E. Sky Harbor Circle Phoenix, AZ 85034

2 of 3 

### OI331-18R4 May 26, 2009 represents a low flight idle, minimum power c ondition. There will be no re sponse to power lever

movements.

ENGINE RESPONSE FOLLOWING A FU EL CONTROL DRIVE FAILURE DURING

DIFFERENT PHASES OF OPERATION

 ENGINES WITH FUEL CONTROLS TH AT ARE NOT IN COMPLIANCE WITH SERVICE BULLETINS TPE331-A73-0254, TPE331-A73-0262 AND TPE331-A73-0271:

- During ground engine starts (with the propeller ON the start locks).

WARNING

- END – During ground engine starts (with the propeller ON the start locks), the engine will experience a rapid uncommanded, uncontrolled acceleration to an overspeed condition sufficient to cause an uncontained separation of high speed rotating

com p onents.

- If an engine exhibits rapidly increasi ng RPM above normal idle values, immediately abort the engine start.

- During ground or flight operation (with th e propeller OFF the start locks), the engine will experience a rapid uncommanded, uncontrolled increase in RPM, torque and/or turbine temperature (the engine may exceed RPM, tor que and/or turbine temperature limits) and

increased forward thrust. Reverse thrust will not be available.

- In the event of a ra pid uncontrolled fuel flow increas e with a subsequent increase in RPM, torque and/or turbine temperature, a nd if engine power fails to respond when the power lever is retarde d, shut down the affected engine as soon as possible consistent with safe operation of the aircraft. Do not move the power lever aft of flight idle.Honeywell International 

# Operating Information Letter 1944 E. Sky Harbor Circle Phoenix, AZ 85034

3 of 3 

### OI331-18R4 May 26, 2009 WARNING

The onset of the conditions listed above is rapid, uncommanded and uncontrolled. Honeywell recognizes the numerous combinations of engines, propellers and airframes to which OI331-18R4 is applicable. Therefore, Honeywell cannot assess whic h of the conditions listed above will be present or the severity to wh ich they will be present for each installation. Honeywell strongly re commends that the aircraft owner consult the holder of the Type Certifi cate or Supplemental Type Certificate

for their aircraft in order to evaluate the extent to which these conditions

will exist.

CAUTION

If an engine exhibits an uncontrolled fuel flow condition, never retard the

p ower levers aft of fli g ht idle.

CAUTION

If an engine has been shut down in flight or on the ground as a result of exhibiting a rapid uncontrolled increase in RPM, torque and/or turbine temperature, do not attempt a ground st art until after inspecting the fuel

control drive in accordance with th e applicable Service Bulletin or

Maintenance Manual.

 ENGINES WITH FUEL CONT ROLS THAT ARE IN COMP LIANCE WITH SERVICE BULLETINS TPE331-A73-0254, TPE331-A73-0262 AND TPE331-A73-0271:

- During certain high altitude ground engine starts (with the propeller on the start locks)

, the modified fuel control may pr ovide fuel flow that is suffici ent to cause the engine to accelerate to an overspeed condition and cause an uncontained separation of high speed rotating components. Initiate an emergency shutdown of the affected engine before the engine speed exceeds 105.5 percent RPM.

- During ground or flight operation (with th e propeller off the start locks), the engine will not respond to power lever movements. Fuel flow will be limited to approximately 180 pph, which represents a low flight idle, minimum power condition.

Note: As with any document that has been revised, as OI331-18 has, discard any and all revisions prior to OI331-18R4. Appl y only the information communicated in OI331-18R4.

- END -