TFE731 Spring 2001

• Revised Fan Disc Replacement Schedule
• HP Impeller Inspection

Revised Fan Disc Replacement Schedule

— Mike Healzer

Duncan Aviation has received several calls from operators regarding the alert SB TFE731-A72-3668. This SB revises the replacement schedule for “old style” 731-2/2A/3/3A/3B/3C/3D/4 fan discs (P/N 3072162, 3072816, 3073539). The replacement schedule has been revised, so when the following conditions are met, the fan disc must be replaced:

1. The next time the fan shaft is unstretched for any reason.
2. At the accumulation of 4,100 or 4,600 fan disc cycles since new depending on your P/N, or by December 31, 2002.

No failures have occurred to precipitate the revised replacement schedule. The affected fan discs remain safe to operate. The fan rotor disc cycle service limit has been re-evaluated based on returned discs from the field. Material and statistical analysis of the eddy current data was done on the returned fan discs. As a result, TFE731-A72- 3668 was issued to simply accelerate the attrition rate of these fan discs. MSP will not authorize early replacement of these discs if the conditions listed above are not expected to happen prior to December 31, 2002.

Honeywell is creating a special program to allow Non-MSP operators to purchase the new fan disc at a prorated price, taking into account the cycles used on the fan disc being removed. Fan disc price will not exceed $27,247 regardless of cycles. MSP operators will receive the fan disk at no charge, with the Service Center billing MSP through the normal claim process.

The prorated price is available one time only and will require that the removed fan disk be returned to Honeywell.

HP Impeller Inspection

— Mike Healzer

Duncan Aviation has also received calls from operators regarding alert SB TFE731-A72-3641. This SB establishes initial and repetitive eddy current inspection to specific identified HP impellers in TFE731-2/3/4/5 engines. Inspections are required at the following events, whichever comes first:

1. The next CZI.
2. When the HP impeller is accessed and has accumulated more than 1,000 cycles since the last eddy current inspection. (access is defined as whenever the LP compressor case is removed from the compressor interstage diffuser) MSP will not authorize early compliance of this SB unless one of the above conditions is met.

Honeywell is creating a special program, which provides several options if an indication is found on the impeller. The options depend on where the indication is found. If an indication is found in the Seal area:

1. A new part can be installed at a prorated price.
2. If an exchange is available within 100 cycles, it can be installed at no charge.
3. If an exchange is desired and available, but not within 100 cycles, you will be credited a prorated price if your removed part has less cycles than the exchange part. You will be charged a prorated price if your removed part has more cycles than the exchange part.
4. Your part can be reworked at no charge.

If an indication is found in the Bore area:

1. A new part can be installed at a prorated price.

If an indication is found in the Backface area:

1. A new part can be installed at a prorated price.

The prorated price is available one time only and will require that the removed impeller be returned to Honeywell.

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