Tornado Alley Turbo, Inc. TAT SB11-07

this event in connection with the damaged cylinder shown in Figure 2, above. This rapid (≈1.5 to 3.5 degrees F / second) increase in cylinder head temperatures, if not corrected immediately, may cause, and has caused destruction of piston rings and pistons as shown in Figure 2, above. This piston and ring damage will normally cause the crank case to become pressurized from the pumping action of the piston and oil can then be forced out of the crank case breather until the engine oil pressure drops to zero. This may lead to engine stoppage and a forced landing. Figure 4. CORRECTIVE PILOT ACTION: In the event a very rapid and unusual rise in any CHT is observed, the pilot should (altitude permitting) immediately reduce the power with the throttle to idle for 3 to 5 seconds and then advance the power with a full rich mixture to the minimum power level required to maintain flight. Thereafter, land at the first available opportunity and ground the aircraft until the cause is determined and corrected. Performing this corrective action before the CHT exceeds the normal engine redline CHT (500 degrees F) will likely, but not necessarily, prevent significant damage to the engine. Tornado Alley Turbo, Inc. TAT SB11-07 300 Airport Road October 12, 2011 Ada, Ok 74820 Page 4 of 4 Phone: (580)332-3510 ACTIONS REQUIRED: Pilots of aircraft covered by this mandatory service bulletin should be made aware of the issue and should be specifically provided and made aware of the Corrective Pilot Action described above, and the information in paragraph 3 of the Accomplishment Instructions, below. Check engine logbooks within ten days of the date of this service bulletin. If logbooks indicate that Champion RHB29E or RHB32E spark plugs or other spark plug manufacturer equivalent spark plugs are installed, no further action is necessary under this Mandatory Service Bulletin, other than a log book entry showing compliance. If the engine logbooks do not clearly document the specific type of spark plugs in the engine, or if Champion RHB36S or RHB32S spark plugs are installed, perform the steps listed in the Accomplishment Instructions within 50 hours or at the next scheduled maintenance event, whichever comes first. When spark plugs are to be replaced, replace them with one of the following spark plugs: • Champion RHB29E (preferred) • Champion RHB32E (acceptable if 29 heat range massive electrode plugs are not available) • Autolite URHB32E (acceptable if 29 heat range massive electrode plugs are not available) • Tempest URHB32E (acceptable if 29 heat range massive electrode plugs are not available) • Any other spark plug listed in Tornado Alley Turbo, Inc. Service Instructions to be issued subsequent to this Service Bulletin WARRANTY INFORMATION Parts and labor are not covered under warranty. MANPOWER REQUIREMENTS For replacement of 8 spark plugs in one engine: One mechanic, ¾ to 1 hour. WEIGHT AND BALANCE: Weight change: None. ACCOMPLISHMENT INSTRUCTIONS 1. Prior to reaching 50 hours TIS from date of this service bulletin or at next scheduled maintenance event, whichever comes first, replace spark plugs with approved spark plugs from list above. 2. Maintain spark plugs in accordance with standard maintenance practices. Inspect, recondition, regap, and test spark plugs on intervals recommended by engine manufacturer in accordance with spark plug manufacturer’s service manual (for example: Champion document AV6-R). Experience with each particular engine may suggest modified inspection, reconditioning, and regapping intervals. Replace spark plugs with approved spark plugs when necessary. Checking spark plug gaps and deposits at appropriate regular intervals is crucial to preventing engine misfires. 3. Pending the accomplishment of the removal and replacement of the RHB32S fine wire spark plugs as described in step 1 above, if, at any time, any unusual roughness or other abnormal engine operation is noted, then have the spark plugs removed and replaced with new spark plugs before further flight. At the same time, check remainder of ignition system for other potential causes of engine roughness. 4. Make an appropriate log book entry, documenting that spark plugs are installed in the engine that conform to the requirements of this Mandatory Service Bulletin. PARTS AVAILABILITY Contact Tornado Alley Turbo Inc. for approved spark plugs. Spark plugs may also be obtained from other aviation supply companies.