Ask a Tech:Oil Pressure, GPS Lock

摘要

This month's questions for the tech come from the pilot of a vintage twin Cessna with Continental IO-470 engines. A gear-up landing required engine teardown and ever since, one engine developed attention-getting oil pressure fluctuations. IA Mike Berry helps sort it out. And, a Mooney owner battles GPS navigator reception problems, and Larry Anglisano points the troubleshooting in the right direction. First, the oil pressure trouble. Upon cold startup, the engines' oil pressure goes to the upper middle of the green, nice and quick. When warm and in cruise below 5,000 feet, both engines stabilize at the lowest end of the green. The CHTs (320) and oil temps (middle) are good. I run at 50 degrees lean of peak. My first two oil analyses looked just fine (I've put 50 hours on it-oil burn with Aeroshell 100W appears to be one quart every seven hours on the left engine and every 12 hours on the right). Compressions are good, no metal contamination, and so on.