ASA flight 529

[ifly4food]

There should be an NTSB report on it. Check their website.

It was a Brasilia, N505AS, going into Asheville, NC. I'm not sure exactly what month it was.
The whole thing was real hush-hush. Nobody from the company wants to talk about it, and even the captain of the flight hasn't heard anything else about it. Delta pretty much swept it under the rug. It really surprises me that our pilot group let them get away with this, but let's just say we have "other things" to worry about for now.

In that incident, they encountered an uncontrollable prop overspeed on approach into AVL. It occured at about 8000 feet about a mile outside the OM on a visual approach at night. The captain was the PF. The captain "elected" to land on the runway and showed remarkable skill in landing the airplane in one piece. The FO should also be commended for a speedy recognition of the problem and running of the immediate action items (though they didn't help). The prop hit 160% RPM before the shafts failed, and the airplane descended at about 3000FPM until that failure stopped the prop from turning. They were very lucky.

 

[Beantown]

chperplt, Where can we get this book? -Bean

 

[Huck]

Also on 529 - the taper bore was originally shot-peened after rebuild to smooth out any corkscrew scratches. This step was dropped for economy, and the FAA signed off on the change.

In the "dissimilar metals" of the Brunswick crash - originally these metals were coated so they had the same Rockwell hardness. this step was also dropped for economy - and the FAA signed off on the change there as well.

I just have to ask - 8000' one mile from the marker? Man, I miss those turboprop approaches! Maybe they were on a downwind....

 

[ms6073]

There should be an NTSB report on it. Check their website.

It was a Brasilia, N505AS, going into Asheville, NC. I'm not sure exactly what month it was.
The whole thing was real hush-hush. Nobody from the company wants to talk about it, and even the captain of the flight hasn't heard anything else about it. Delta pretty much swept it under the rug. It really surprises me that our pilot group let them get away with this, but let's just say we have "other things" to worry about for now.

Although my search of the NTSB archives could hardly be considered conclusive, I guess the company 'really' did sweep this under the rug. I was unable to find any accident synopsis that was similar in nature to the events you described between 01/01/97 to present for all events in North Carolina much less the U.S.???

 

[Typhoon1244]

The Brasilia has five features/systems designed to prevent a prop overspeed...all dependant on oil pressure.

My wife's maternal grandfather flew P-61 night-fighters in the Pacific during W.W. II. I was reading one of his books a while back, and I read that the first Black Widows suffered a lot of problems early on because their Hamilton Standard props were over-speeding.

See? The '120 is carrying on a sixty-year Ham-Stan tradition!

 

[avbug]

Loss of the aircraft during most overspeed situations is pilot error. While The overspeed may not be pilot error, failure to contain the overspeed certainly can be. In any event, one can only make the best of a situation that hopefully he does not create.

I recall a C-119 crash some time ago, which occured on a training flight. An overspeed occured, and the crew fought to controll it, while losing altitude. After 1/2 hour of struggling with the airplane, they crashed. The scenario involved in this case an engine that was developing good power, but had a prop overspeed.

Power was pulled, airspeed lost, altitude lost, and the RPM brought under control. As the aircraft slowed and became hairy, power was added, altitude and airspeed gained (or maintained), and a cycle was formed.

What the crew failed to grasp was that the RPM of the propeller, whenever not under positive torque, was dependent on airspeed. Had they slowed the aircraft and then used available power on the engine, they could have returned and landed normally...instead of dying.

If the engine isn't driving the prop, then the slipstream is. Reducing the relative wind that's driving the prop will reduce the prop velocity. This seems somewhat counterintuitive, as it brings the airplane to a state of reduced lift and potential controllability, however, it's what must happen. (Much like pulling aft and pulling power off during a tailplane stall in ice).

In the event that the engine can be controlled by reducing to a very slow airspeed, then very often power can be added and used. If it can't be, then the engine should be shut down, feather or not.

The ham standard prop on the brasillia and other modern aircraft is nothing like the hydromatics found on the P-61, and virtually every other aircraft of it's era. However, the principle remains the same. Ham standard props are well designed, tough, and reliable. I've rested my life on them, earned a living from them, and have handled them in all states from flawless function to destroyed. I've worked on them, overhauled them, and think the world of them. Don't blame the prop...it's nothing more than a mechanical device. The key is what is done with it when something does go wrong.

In the case of 529, it would appear the crew did it right. Unfortunately, it's very possible to do everything right...and still lose.

 

[Huck]

The Brasilia's a special case avbug. Read the report on the ASA Brunswick crash. It oversped on base-to-final at ~120 knots. The resulting torque roll threw them on their backs before they could try anything, much less slow down. The captain was the first American typed in the EMB120 and the head of the training department.

Ham Standard also blamed the crew, until Embraer actually recreated the torque tube failure on a test aircraft. From stable at 8000', it basically did a split S onto the runway - I believe the pilot (flying solo) was named Schittini.

The 14RF9 is a scimitar-shaped blade that acts like a pinwheel when the torque tube is cut. You're right, not comparable to older straight props.

 

[aceshigh]

Hey Bean et al.,

If you want to get a copy of the book, check your local library. I did on a whim and was surprised to find that they had four copies of the book. I was also surprised to find a lot of the books mentioned on the thread about what everyone is reading, including Fate is the Hunter. Just a thought to save some $$$.

Aceshigh

 

[KingAirer]

Whats the name of this ASA book?

 

[demo]

Although my search of the NTSB archives could hardly be considered conclusive, I guess the company 'really' did sweep this under the rug. I was unable to find any accident synopsis that was similar in nature to the events you described between 01/01/97 to present for all events in North Carolina much less the U.S.???

It happened in '95... here's a link to the synopsis: http://www.ntsb.gov/ntsb/brief.asp?ev_id=20001207X04223&key=1
but the final report you have to order from them in hardcopy.