Propeller strap strikes passenger after take off from Canberra
It is possible the strap part was detached, but left on the blade and the stair barrier removed thinking they had the whole assembly. That would then make sense that the start encountered no abnormality as it would have wound up freely with the strap just rotating with the blade.
It's hard to understand how the strap remained on a blade if the a/c was taxied with both engines unfeathered and only detached on the runway after TO power applied.Can't remember prop RPM on taxi but it is significant.
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So, what I don't get is why they didn't reject the takeoff. Surely that's SOP if you hear a loud bang during the takeoff roll??
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Who said anything about condition lever being out of feather? The CL start detent IS feather. If you actually read my post I wrote, "mechanic could hold the prop stationary while you started it."
Should have been removed by crew as part of pre flight.. Loganair require a tech log entry to say prop straps are fitted. Crew can remove and sign. We have already been told about it. The penetrating item is the securing pip pin that holds the prop strop to the nacelle. Throw off the strop spinning at 1000 RPM .
From the ATSB Summary https://www.atsb.gov.au/publications...rt/ao-2022-055
Aircraft Details
Fly Safe
PJ88
Aircraft Details
- Model SAAB 340B
- Damage Minor
- Destroyed : The aircraft is not repairable, or, if repairable, the cost of repairs exceeds 50% of the cost of the aircraft when it was new
- Substantial : Damage or failure that adversely affects the structural strength, performance, or flight characteristics of the aircraft, and which would normally require major repair or replacement of the affected component. Not considered in substantial damage are; engine failure or damage limited to an engine only, bent or dented skin, damage to landing gear (to include wheels and tires), flaps, or wingtips.
- Minor : Damage that neither destroys the aircraft nor causes substantial damage.
Fly Safe
PJ88
Impossible for a person to hold prop stationary once condition lever moved out of feather
Should have been removed by crew as part of pre flight.. Loganair require a tech log entry to say prop straps are fitted. Crew can remove and sign. We have already been told about it. The penetrating item is the securing pip pin that holds the prop strop to the nacelle. Throw off the strop spinning at 1000 RPM .
BTW starting with the prop brake engaged is not done, its started then braked. From what I've heard starting with a prop strap on is very noticeable, so if the start is monitored as it should be you would notice an abnormal temp and then possibly sudden release when the straps let loose. There is no way they got to lineup not noticing a prop was still stationary, that is definitely beyond belief. So the prop must have been rotating from start at some point and come out of feather as normal.
Indeed, if the photos are genuine the categorisation of the damage as “Minor” is laughable.
I'm more amused at why the QLink brake fire is not listed on ATSB yet... Definitely damage to the wheel assembly and legs from the footage, probably more costly than this fix, and something new that warrants the ATSB having a look see as well as having a look over the evacuation procedures. And then the two Jets that descended below minimum altitude in Cairns has missed the news conveniently.
Last edited by 43Inches; 12th Nov 2022 at 00:04.
By all means though, be my guest.
I'm more amused at why the QLink brake fire is not listed on ATSB yet... Definitely damage to the wheel assembly and legs from the footage, probably more costly than this fix, and something new that warrants the ATSB having a look see as well as having a look over the evacuation procedures. And then the two Jets that descended below minimum altitude in Cairns has missed the news conveniently.
Anyone who has spent time at this company in the last few years won’t be surprised that a serious incident has occurred, or more correctly, a serious incident that wasn’t able to be swept under the carpet.
That is remarkable...
At takeoff, ruffly, the trebuchet would have had about 5500g of radial acceleration going on... and for a 0.4kg mass (what does it weigh? 100gms), the force of the release is around... 22KN... and a velocity of around 330m/sec. That it then popped a hole in the tub is not a surprise. What is a surprise is that it was tenacious enough to hang in there until the takeoff, that takes some amazing schtick.
The imbalance on a prop is surprisingly well damped by Mother Earth when the plane is on the ground, once airborne, all bets are off and the vibration can be spectacular...
Back in about 84, a certain "Brand X" P3C ripped up 2 star pickets, and tore the cuff off a blade which was not noticeable on the ground, but got the total attention of the crew as the gear came off the ground. Was a short flight.
At takeoff, ruffly, the trebuchet would have had about 5500g of radial acceleration going on... and for a 0.4kg mass (what does it weigh? 100gms), the force of the release is around... 22KN... and a velocity of around 330m/sec. That it then popped a hole in the tub is not a surprise. What is a surprise is that it was tenacious enough to hang in there until the takeoff, that takes some amazing schtick.
The imbalance on a prop is surprisingly well damped by Mother Earth when the plane is on the ground, once airborne, all bets are off and the vibration can be spectacular...
Back in about 84, a certain "Brand X" P3C ripped up 2 star pickets, and tore the cuff off a blade which was not noticeable on the ground, but got the total attention of the crew as the gear came off the ground. Was a short flight.
Originally Posted by vegassun View Post
Who said anything about condition lever being out of feather? The CL start detent IS feather. If you actually read my post I wrote, "mechanic could hold the prop stationary while you started it."
Who said anything about condition lever being out of feather? The CL start detent IS feather. If you actually read my post I wrote, "mechanic could hold the prop stationary while you started it."
Posted by Krusty I've more than 15,000 hours on type, and I would suggest such an action would be both the first and the last time any individual tried that!
From what I've heard starting with a prop strap on is very noticeable, so if the start is monitored as it should be you would notice an abnormal temp
Particular aircraft have their own idiosyncrasies. The Britannia had a 4,450SHP Proteus free turbine and the prop remained in positive pitch upon shutdown, a prop brake held all props after shutdown and was released prior to start, if there was a wind present from the rear that caused the prop to rotate in the opposite direction it could pick up a considerable rotation speed in the wrong direction which caused considerable bearing load and adverse effects of gas temps over the turbine-before rotating in the intended direction, rather like starting with the wind from the rear on some aircraft. The procedure was to hold a blade between finger and thumb until the turbine began to drive the prop shaft, the blade then moved ever so gently out of the holder's finger/thumb.
Have had to have aircraft repositioned on rare occasions when wind up the rear caused start EGT issues.
My experience with free turbines on helicopters and starting with the rotor held by the aircraft fitted brake or rotor held by an engineer until he no longer could there was no difference in start parameters, in particular EGT.
Where do I find “time in the shop” and “cost of the repair” in the damage categorisation definitions for the purpose of ATSB investigations? If the pictures are genuine, there’s a hole punched through the fuselage … of a pressurised aircraft … that had passengers on board.
My apologies. I didn’t realise you were an aeronautical engineer with expertise on the type.