OKLAHOMA CITY — U.S. Sen. Jim Inhofe walked away from the forced landing of his small plane amid severe weekend weather — the latest of several troubled landings for the avid pilot, who at 81 shows no signs of leaving the cockpit. The Republican senator brought his plane down in Ketchum, a small community in far northeastern Oklahoma, spokeswoman Donelle Harder said Monday. There is no maximum age for pilots — some fly well into their 90s, said Lynn Lunsford, a spokesman for the Federal Aviation Administration. “All pilots must pass regular physical exams and take a check ride every two years to demonstrate proficiency,” he wrote in an email to The Associated Press.