Lear 25 Stall Characteristics
PJ2,
I can shed no light on stall characteristics as all our Learjet training was 'approach to stall' in the aircraft, in the usual three different configurations. Your question is a good one as that could be one of the upset scenarios - but not likely at FL280 given the normal fast climb and cruise profile.
This aircraft probably had its original ancient 'iron gyros' for vertical reference, with their life limited by ball bearings. Imagine the left side attitude indicator tumbling in front of the elderly captain. Imagine his gyro tumbling in incapacitation, with little experience or command presence in the right seat.
The autopilot was notoriously bad even by standards of the day. Legend had it Bill Lear wanted absolute minimum weight and cost, so would not use an autopilot built by a 'real' company like Collins or Bendix-King. The altitude hold function was unlike any other aircraft I've flown... very poor.
Anyone know if this was an RVSM aircraft? I'll bet not, given the $250,000 price tag mentioned in the press and the 28,000 foot altitude of apparent cruise flight. Hard to believe Jenni Rivera ended up in this clunker, given its history, its owner and its crew... very sad.