A Fokker 27 loses it's propeller at take-off in Paris (CDG)
Sorry gentlemen if I created a tangent there with my remark about 'engine autofeather' which should of course be propeller autofeather. 
From the pictures the prop is certainly not feathered, but the conditions for an autofeather would surely have been present - throttles above 13,000 RPM, HP cock in Fuel On or Lock Out, torque below 40 PSI and decreasing. An autofeather will take about 2 or 3 seconds to complete, and that failure would have been instantaneous, but since the conditions for an autofeather existed the engine should have shut itself down via the autofeather feature.
Well said, that was my take on it also.
From the pictures the prop is certainly not feathered, but the conditions for an autofeather would surely have been present - throttles above 13,000 RPM, HP cock in Fuel On or Lock Out, torque below 40 PSI and decreasing. An autofeather will take about 2 or 3 seconds to complete, and that failure would have been instantaneous, but since the conditions for an autofeather existed the engine should have shut itself down via the autofeather feature.
I don't think "total loss of the front half of the engine" is covered by the checklist.
The Darts on the Viscount had autofeather and Ground Fine Pitch.
People would love to see some of the museum Viscounts flying and/or taxiing, but the Darts on them have no provision for borescoping; so, you have to unbolt the whole thing for an inspection
People would love to see some of the museum Viscounts flying and/or taxiing, but the Darts on them have no provision for borescoping; so, you have to unbolt the whole thing for an inspection
Like I said, it's been a long time, but I'm pretty sure the F27 didn't have autofeather, and it certainly didn't have a yaw-damper. My comment about glass was merely to observe that these guys were able to "think outside the box",and I can't see where Pailot77 is coming from regarding SOPs. I don't think "total loss of the front half of the engine" is covered by the checklist.
Managed to restart one engine and land ok. Nearly lost that one.
After modification with the disarm switch, standard procedure to disarm in moderate/severe turbulence.
I think the guys in Paris did a stellar job, not all situations are covered by SOP or checklists...
Last edited by oceancrosser; 2nd Nov 2013 at 03:28.
"Mildly" Eccentric Stardriver
I think I'd blanked out the autofeather, like you blank out unpleasant memories. First start of the day, playing an opera on the levers, hoping to avoid running out of fluid and having a prop stuck half-feathered. My excuse is twenty-five years, three jet types and nine-year's retirement. Another senior moment.
First start of the day, playing an opera on the levers, hoping to avoid running out of fluid and having a prop stuck half-feathered....Another senior moment.
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Please.
Back to basics.
A prop turning at 1200rpm is producing lift forwards.
The prop on coming loose will out accelerate the aircraft.
A turbine blade turning at 30,000rpm coming loose will move sideways.
Just my take.
A prop turning at 1200rpm is producing lift forwards.
The prop on coming loose will out accelerate the aircraft.
A turbine blade turning at 30,000rpm coming loose will move sideways.
Just my take.
Back to basics.
assuming that it's still attached to an engine centerline
it will quickly stall out lift and lose rotational speed due to drag
at least tangential until it hits something like another blade in which case it gets deflected fore or aft
A prop turning at 1200rpm is producing lift forwards.
The prop on coming loose will out accelerate the aircraft.
A turbine blade turning at 30,000rpm coming loose will move sideways.
lomapaseo,
Thanks for that interesting graphic on the trajectory of a detached propellor blade.
N707ZS,
"Chris, obviously two propeller [blades], original quick thought was a third one was visable on the back of the lorry left hand side above the lights, black object."
So it seems 2 propellor blades are still missing, including the one that passed through the fuselage.
Thanks for that interesting graphic on the trajectory of a detached propellor blade.
N707ZS,
"Chris, obviously two propeller [blades], original quick thought was a third one was visable on the back of the lorry left hand side above the lights, black object."
So it seems 2 propellor blades are still missing, including the one that passed through the fuselage.
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F27 prop failure at CDG
Hi guys I am new to this, actually retired. I flew F27's and may well have flown the very same aircraft as I have been detached to MNL for a while.
If so, it would have been Swiss registered at the time.
For the record: this was NOT an accident but an incident. Nobody was injured. The aircraft landed safely.
Fortunately, blade separation is exceedingly rare.
I was a pilot for over 45 years and not counting piston-engined aircraft or jets I flew probably close to 8000 hours on turboprops: Shorts Skyvan, 3-60, Metroliner, King Air 200, ATR 42, Fairchild FH227, Fokker 50 and about 4500 hours on the Fokker F 27. I never encountered a blade separation.
Looking at the pics, my guess is that the sequence of events went as follows:
A hub failure caused a blade to separate.
This blade flew straight through the fuselage. The sides are protected against damage from ice flung off the prop but the reinforcements are no match for a blade flying off at high power. It had so much energy that it went straight out through the other side. But by that time most of the energy would have been expended so it did not hit the other engine.
A cargo plane does not carry passengers and there are no vital systems in the area the blade passed through so all systems continued to operate as normal.
The blade separation would have caused severe vibrations, enough to shear off the front part of the engine with the remainder of the prop instantly. These parts would have totally different aerodynamic characteristics and would have fallen downwards without doing any more damage.
Return to the airport on one engine would have been routine, I have had to return an F27 on one engine twice, nothing to it. But the crew must have been very shaken by the event and are to be complimented with the obviously highly professional way the incident was handled.
This scenario is my own educated guess. It will be interesting to read the official findings of the investigation.
If so, it would have been Swiss registered at the time.
For the record: this was NOT an accident but an incident. Nobody was injured. The aircraft landed safely.
Fortunately, blade separation is exceedingly rare.
I was a pilot for over 45 years and not counting piston-engined aircraft or jets I flew probably close to 8000 hours on turboprops: Shorts Skyvan, 3-60, Metroliner, King Air 200, ATR 42, Fairchild FH227, Fokker 50 and about 4500 hours on the Fokker F 27. I never encountered a blade separation.
Looking at the pics, my guess is that the sequence of events went as follows:
A hub failure caused a blade to separate.
This blade flew straight through the fuselage. The sides are protected against damage from ice flung off the prop but the reinforcements are no match for a blade flying off at high power. It had so much energy that it went straight out through the other side. But by that time most of the energy would have been expended so it did not hit the other engine.
A cargo plane does not carry passengers and there are no vital systems in the area the blade passed through so all systems continued to operate as normal.
The blade separation would have caused severe vibrations, enough to shear off the front part of the engine with the remainder of the prop instantly. These parts would have totally different aerodynamic characteristics and would have fallen downwards without doing any more damage.
Return to the airport on one engine would have been routine, I have had to return an F27 on one engine twice, nothing to it. But the crew must have been very shaken by the event and are to be complimented with the obviously highly professional way the incident was handled.
This scenario is my own educated guess. It will be interesting to read the official findings of the investigation.
Hi Rudy Jakma, and welcome.
DaveReidUK is right; "substantially damaged" is the other criterion you may have forgotten.
The BEA released a statement on 27 October, as many of you will have noted:
Fokker 27, Paris Charles de Gaulle Airport, France, 25 Octobre 2013
Today's version in French adds a photo of the propeller hub:
Fokker 27, 25 octobre 2013, aérodrome de Roissy Charles de Gaulle (93)
The caption:
Vis de fixation en place dans la pale, présentant des caractéristiques de rupture en fatigue (lignes d'arrêt).
Des examens plus approfondis vont être entrepris sur la pale d'hélice.
Roughly translated:
Fixation screw in place in the blade, presenting characteristics of fatigue-rupture.
A more thorough examination is going to be carried out on the propeller blade.
Does that mean they have found the missing blade, I wonder?
I infer that the BEA regards the blade mounting screw (to the hub) as the primary failure.
DaveReidUK is right; "substantially damaged" is the other criterion you may have forgotten.
The BEA released a statement on 27 October, as many of you will have noted:
Fokker 27, Paris Charles de Gaulle Airport, France, 25 Octobre 2013
Today's version in French adds a photo of the propeller hub:
Fokker 27, 25 octobre 2013, aérodrome de Roissy Charles de Gaulle (93)
The caption:
Vis de fixation en place dans la pale, présentant des caractéristiques de rupture en fatigue (lignes d'arrêt).
Des examens plus approfondis vont être entrepris sur la pale d'hélice.
Roughly translated:
Fixation screw in place in the blade, presenting characteristics of fatigue-rupture.
A more thorough examination is going to be carried out on the propeller blade.
Does that mean they have found the missing blade, I wonder?
I infer that the BEA regards the blade mounting screw (to the hub) as the primary failure.
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Qoute... Does that mean they have found the missing blade, I wonder?
They may still be looking for it in Germany...
The photo of the fracture seems to reveal the start of a stress fracture at the 10 or 11 o/clock position, in the position of the black marks. Then the fine tree-ring like lines in the 12 o/c position show the repeated cyclic stress failures. Either these occurred every rev of the prop, or it could have been once every-time the prop exceeded a certain amount of torque. (maybe only once per flight.. who knows?)
They may still be looking for it in Germany...
The photo of the fracture seems to reveal the start of a stress fracture at the 10 or 11 o/clock position, in the position of the black marks. Then the fine tree-ring like lines in the 12 o/c position show the repeated cyclic stress failures. Either these occurred every rev of the prop, or it could have been once every-time the prop exceeded a certain amount of torque. (maybe only once per flight.. who knows?)
Par ailleurs, la pale d'hélice en traversant le fuselage de l'avion a sectionné les câbles d'alimentation des enregistreurs de vol.
De ce fait, aucune donnée de l'événement n'a été enregistrée
De ce fait, aucune donnée de l'événement n'a été enregistrée
...or it could have been once every-time the prop exceeded a certain amount of torque.
For what it's worth, I think Rudy has the sequence of the break-up correct.
So, how many times had it gone through overhaul and repair where such a massive propagation had gone undetected even as the fracture surface may have been discolored by cleaning agents etc.
Like engine rotor disks the safety of flight is provided by robust overhaul cleaning and NDI to catch cracks before they propagate to complete fracture. It would be very rare to have an operational annomaly that would result in fatigue propagation between overhaul periods on such a critical part.
Like engine rotor disks the safety of flight is provided by robust overhaul cleaning and NDI to catch cracks before they propagate to complete fracture. It would be very rare to have an operational annomaly that would result in fatigue propagation between overhaul periods on such a critical part.
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From the BEA site picture:
For the uninitiated, Looks like the crack initiated at what appears to be the base of some circumferential threads and proceeded to grow fanwise from the 9:30 direction before the stress changed into the propeller spanwise direction. From there, it proceeded very rapidly until it reached the central bore and an instantaneous failure of the remaining 2/3 of the blade shank tore away the remainder of the blade.
For the uninitiated, Looks like the crack initiated at what appears to be the base of some circumferential threads and proceeded to grow fanwise from the 9:30 direction before the stress changed into the propeller spanwise direction. From there, it proceeded very rapidly until it reached the central bore and an instantaneous failure of the remaining 2/3 of the blade shank tore away the remainder of the blade.
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The other noteworthy point in the 8th Nov. update is that there is no FDR/CVR data post blade flying through the fuselage: doing so, it severed the power supply cables for the recorders.
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lomapaseo:
This factor has showed up in a number of uncontained engine failures. The UAL CF6 fan disc (Sioux City) is a notorious example; UAL's NDT inspection was shown to be "lightweight" and a major contributor, in that the incipient failure was readily detectable by best practices.
So, how many times had it gone through overhaul and repair where such a massive propagation had gone undetected even as the fracture surface may have been discolored by cleaning agents etc.
"Mildly" Eccentric Stardriver
Sky Captain. It's how you treat the old girl. 
I flew them for ten years in the UK and only had three shutdowns. None the fault of the engine per se. Two gearbox failures (mandatory shutdown) and one fuel starvation..
I flew them for ten years in the UK and only had three shutdowns. None the fault of the engine per se. Two gearbox failures (mandatory shutdown) and one fuel starvation..
Herod that was pretty well my experience, 25 years and 13,000 hours. Two shutdowns - one false fire warning and one where the engine oil bailed out via a cracked oil cooler.
Last edited by pigboat; 9th Nov 2013 at 22:14.
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How does the venerable Dart failure rate compare with the modern, possibly more delicate "banana" bladed turboprops, or is a MTBF in thousands of hours possible for comparison?
Will they last as long too...........................?
Will they last as long too...........................?