RAM Aircraft, L.P. MANDATORY
SERVICE BULLETIN MSB2003-02
Technical Portions are FAA DER Approved.
Mandatory Replacement of Engine Components, Inc. (ECi)
Part No. AEC631397 Cylinders.
Provide instructions to inspect the cylinder in the Number 6 position and determine if the cylinder must be replaced to avoid possible cylinder head separation and loss of engine power.
Within Next 25 Hours of Operation.
RAM Super and RAM Series III, IV, VI, and VII engines – TSIO-520-NB engines modified by STC SE4327SW, STC SE09104SC, or STC SE09261SC for operation at 325 HP or greater.
Over the past several months, customers have reported partial head separations of ECi part number AEC631397 cylinders. The ECi cylinder failures have primarily occurred at the Number 6 cylinder position on aircraft with 325 HP or greater engines. The cylinder heads have typically cracked between the ninth and tenth cooling fin (counting from the head/barrel junction), starting on the exhaust side of the cylinder head. Most failures have come within the first 100 hours of operation.
Analysis of the cylinder failures led to the discovery that ECi did not properly execute the artificial aging (heating) process, one of the cylinder head manufacturing steps, before assembling the cylinder head on the cylinder barrel. The incomplete process causes the cylinder head to remain in an overly hardened condition, which reduces the cylinder’s tolerance to stress and increases the chance that the cylinder will crack. As long as a crack does not start early on, the cylinder will naturally age during operation, thereby making the cylinder head more ductile and less likely to crack.
The Number 6 cylinder is most susceptible to failure while in this overly hardened condition due to its’ proximity to the engine nacelle cooling air inlet. The combination of the hardened material and extreme temperature gradient at the exhaust side of the Number 6 cylinder further increases the chance that the cylinder will develop a stress crack. The failure mode is similar to cylinder cracking that occurs when an engine is subjected to shock cooling. The remaining cylinder positions do not see quite as extreme a temperature gradient as the Number 6 cylinder. Therefore, the other five cylinders are more likely to naturally age than develop a crack and fail. Only cylinder Number 6 is subject to the requirements of this service bulletin.
By April 22, 2003, ECi corrected their cylinder head manufacturing problem. Only ECi part number AEC631397 cylinders manufactured from September 1, 2002 through April 21, 2003 are susceptible to possible fatigue cracking and head separation. NOTE: ECi part number AEC631397 cylinders can be identified by the letters “ECi” and “AEC65385” cast into the cylinder head at the rocker box. ECi part number AEC631397 cylinders manufactured after April 21, 2003 have an “A” stamp on the top of the rocker box flange.
Once the problem was discovered, ECi issued ECi Mandatory Service Bulletin 03-7 on July 3, 2003 to have engine owners inspect their Number 6 cylinders. The ECi bulletin affects Teledyne Continental Motors (CMI) TSIO-520 engines that are rated at 325 HP or greater with ECi part number AEC631397 cylinders. If there is an “A” stamp on the rocker box flange, the cylinder has been manufactured properly and is not affected by the ECi service bulletin. If the cylinder does not have an “A” stamp, ECi initially recommended owners inspect the Number 6 cylinder for cracks between the ninth and tenth cooling fins, and repeat the inspection every 100 hours until the engine reaches 500 hours.
ECi revised their service bulletin and issued ECi MSB 03-7 Revision A on August 8, 2003, which now requires owners replace ECi part number AEC631397 cylinders installed in the Number 6 position that do not have an “A” stamp on the rocker box flange. Replacing the Number 6 cylinder eliminates the repetitive inspection required by the original ECi service bulletin.
RAM Aircraft, L.P. owns STC SE4327SW, STC SE09104SC, and STC SE09261SC that increase CMI TSIO-520-NB engines from 310 HP to operation at 325 HP or greater. ECi part number AEC631397 cylinders have failed on TSIO-520-NB engines modified for operation at 325 HP or greater. Therefore, RAM Aircraft, L.P. has determined that it is necessary for owners of these engines to inspect and replace their cylinders where applicable. Follow the instructions provided in the next section in order to comply with the requirements of RAM Aircraft, L.P. MSB2002-03.
1. Determine whether or not ECi part number AEC631397 cylinders are installed on the aircraft (right hand AND left hand engines).
2. If cylinders are not ECi part number AEC631397, then go to Step 5.
3. CYLINDER INSPECTION:
a. Following the aircraft manufacturer’s instructions, perform the following:
i. Disconnect the aircraft battery.
ii. Remove the nacelle cowling.
b. If cylinder manufacturer is unknown, remove rocker box cover of Number 6 cylinder. If the letters “ECi” and “AEC65385” are cast into the cylinder head, then it is an ECi part number AEC631397 cylinder.
c. If cylinders are ECi part number AEC631397, inspect the top of the Number 6 cylinder rocker box flange. If there is an “A” stamp on the flange, then the cylinder does not require replacement. Proceed to Step 5.
4. CYLINDER REPLACEMENT:
a. If ECi part number AEC631397cylinder in the Number 6 position does not have an “A” stamp on the top of the rocker box flange, then replace the cylinder.
i. Remove the engine exhaust, intake, baffle, fuel lines, ignition cables, spark plugs, rocker cover, and gasket from the Number 6 cylinder.
ii. Remove Number 6 cylinder in accordance with CMI cylinder disassembly instructions (CMI manual no. X30574A).
b. Contact RAM Aircraft, L.P. for cylinder exchange and labor reimbursement information.
c. Install replacement cylinder and attaching parts in accordance with CMI service instructions and RAM engine STC service instructions.
d. Follow RAM Aircraft, L.P. break-in procedures attached with replacement cylinder.
5. Make a logbook entry that compliance with RAM Aircraft, L.P. MSB2003-02 and ECi MSB 03-7 Revision A has been met.
CONTACT: For cylinder exchange and labor reimbursement, or for other questions regarding this service bulletin, contact RAM Aircraft, L.P. Customer Service Dept. at (254) 752-8381 (M-F, 8 AM to 5 PM, CDT).