The average DOB on the DC-9-10s was around 1963. They have since been retired. Most of the rest are between 1967 and 1974. Most of the -50s were built in 1978-79.
They are the absolute tops. Best reliability and dispatch record of any aircraft at the majors. I haven't seen a MX CX in many, many months and most MELs, if any, are very minor. I think I've seen only one deferred APU in 3 years.
There really is nothing much to break. No resetting CBs to get the brains back into sync or to reset the IRU. No complicated GPS or RNAV, as they all come equipped with "vector capable" comm radios.
Most of the engines are leased from UAL for pennies on the dollar.
Still, they aren't quite the same as the DC-9s of old. In the overhaul, the interiors were all gutted and have large overhead bins and a 3rd lav up front. Lots of fixes to perennial DC-9 problems, such as gear indicators and fuel gauges, have been upgraded to solid state (proximity switches replaced microswitches, and the fuel gauges are now all digital). The presurization system is all digital now, and is set and forget. Digital altimeters allow for RSVM and new radar displays have the EGPWS. They even have dual nav/com heads (aka primary and standby freqs) and are wired for headsets.
The AC still is weak in the summer...they went old tech for a solution to that one...sun screens. They work unbelievably well.
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ON the other hand, keeping these suckers running has saved them alot of cash. Didn't look all that bad to me. I wonder what the average age on the DC-9 is.
