PIPER PA-31

The Navajo is Piper's eight-seat unpressurised twin, the aeroplane that carried a large share of American commuter and air taxi traffic through the 1970s and 1980s. It cruises at 200 knots with a 2,900 lb useful load and a cabin big enough for six passengers in reasonable comfort. The 310 hp aircraft came in three forms under the one designation. The original Navajo of 1967 had the turbocharged TIO-540-A; the Navajo B of 1971 brought TIO-540-E engines, factory air conditioning and the two things air-taxi operators had asked for, an optional pilot's door up front and an optional wide utility door at the back; the Navajo C of 1974 changed to the TIO-540-A2C and tidied the systems, and ran to the end of production. PA-31 and PA-31-310 are the same aeroplane: the registry carried both spellings until a 1973 airworthiness directive required data plates to read PA-31. For a buyer the B and C are the ones with the doors and the air conditioning, which is most of what separates a usable Navajo from a cheap one.

It is bought today for load and volume rather than refinement, and the economics are commercial rather than private. Two turbocharged Lycoming TIO-540s are expensive to overhaul and unforgiving of careless power handling; the exhaust and turbocharger systems need close annual inspection. An eight-seat twin's annual is a serious event. Many airframes have very high hours and cycles from charter and freight work, so those matter more than the model year. Insurance requires a multi-engine rating and, for commercial use, formal recurrent training.