Very good read. But it is long.
The ultimate reason for the crash
Ditchey echoed other experts, including Bryant’s former pilot, in vouching for the quality of the helicopter. It was built in 1991, and “is not the newest version of that helicopter,” he said. “But in general, it’s a good, solid airplane.”
As for the Flight Radar 24 data, which seem to indicate a sudden nosedive, “I’d take that with a grain of salt,” Ditchey said. “I don’t know where they got that. It may be on the very edge of reliable signals. I wouldn’t believe that figure.”
If the data are accurate, Ditchey did raise one possibility. “If the pilot tries to climb very rapidly, the pilot is then putting heavy load on the rotor,” he explained. “What happens is, the rotor begins to stall, and then begins to slow down. And the only way you can correct that is to go down” – to execute an “autorotation” landing. “Otherwise, if the rotor slows down enough, you will crash. So that could explain the sudden rise and the sudden drop, [if] the main rotor stalled out. ...
“If the main rotor stalls, you just have to hope like hell you have enough room between you and the ground that you can autorotate.”
But Ditchey remains skeptical of the data. Added Browne: “It could indicate a mechanical problem. But I highly doubt it.”
Instead, they all point to the weather. And Ditchey, on this subject – admittedly with the benefit of hindsight – was unequivocal.
“I’m a pilot,” he said. “I flew in the navy for 14 years, actively. There are times when you just don’t go, you just don’t fly, unless there’s a damn good reason why.”https://sports.yahoo.com/kobe-bryants-d ... 03911.html
That is the TRUTH. There are many times on the North Slope when I refused to fly because of weather, but other pilots did fly. I didn't care. Most of them had better equipped aircraft, or they were working in their area of expertise. There were some however that thought they could force a work day week in to a North Slope trip. Some of them aren't with us anymore. Most of them had big egos.
That's the first thing my dad taught me. "Your ego will kill you faster than anything else. Never do something just because someone else did."
He was a Veteran Pilot from WW2, the Berlin Airlift, and retired in 1961 after 20 years in the Air Force. Then he flew 14 years for Wien Air Alaska, and retired. Then he started his own Air Taxi, which is where I got in to flying commercially.
The story above sounds odd the way the pilot is describing it. Maybe the transcriptionist didn't copy it down properly. You can get "retreating blade stall" in a helicopter. That's when you're going too fast forward. Helicopter blades are basically a rotating wing. The advancing blade is going forward through the power of the engine, but it is also meeting the oncoming air, which increases it's lift.
The retreating blade is moving towards the back of the machine, thus creating less lift. That's why the advancing blade has less pitch, and the retreating blade has increased pitch. But at high speeds, the retreating blade has no air movement over it, thus no lift.
Imagine the blade is moving backwards at 180mph, and the helicopter is moving forwards at 180mph. The airspeed over the "retreating wing" is 0mph. No lift. That blade stalls, and the helicopter rolls over.
I too think it was the weather, but I'm also guessing that he got disoriented and stopped doing his instrument scan, My reasoning, he was coming out of the sky at 4000fpm and 160 knots. Those numbers likely came from his Transponder which near any populated area with an airport, is a required piece of equipment. I'm sure the pilot had the transponder set to a unique identifying number so the radar operator, and any other monitoring equipment would have had indentifying information including N number, airspeed, and rate of descent.
I could easily be wrong though. If he did stall the retreating blade, he'd fall out of the sky, but if he lost translational lift, or killed his rotor speed, he would likely be diving the helicopter. That forces air over the rotor blades, speeding them up again. That's what you need to safely auto-rotate, rotor speed.
It's complicated though. I did it a couple of times with an instructor, scary.