Propeller Damage
Irish Steve, sorry but disagree with you conclusions on the prop damage and also a answer to Island Pilots question.
The port propeller is in the feathered position. This could have been feathered by the crew because the engine had stopped producing power.
However, the manufacturer has previously reported instances of the blades moving out of course pitch during impact, particularly where the airframe is still in forward motion with respect to the angle of the propeller blades. This is not uncommon on this type of propeller system.
However, the one port propeller blade is in almost perfect condition indicating little to no rotational speed of the propeller hub upon impact with the ground, with little or no torque applied, consistent with a feathered prop due to the engine not producing power before contact with the ground. All port propeller blades appear to be in the fully feathered position consistent with intentional manipulation of the controls to the stop/feather position of the controls rather than a partial feathered position caused by the impact as seen in some previous incidents.
The post incident shape of the other two port propellers is consistent with impact and post impact dynamics. The dynamics would be a combination of vertical impact force due to the weight of the aircraft and kinetic energy of the rolling motion, with very little forward momentum of the airframe, combined with some kinetic energy from the excursion from the runway, producing lateral movement (form to left to right) of the airframe while coming to rest in it's final inverted position, rather than rotational speed and or torque applied to the hub. Notice that the bend in the propellers is in an anticlockwise direction. Again consistent with the lateral movement of an inverted airframe from left to right.
Propeller contact with the ground with an engine producing high power will normally result in a catastrophic failure of the hub. This will normally cause the propellers to depart from the hub at high velocity. You can see typical evidence of this on the incident aircrafts Starboard propeller hub. i.e. No propeller and visible signs of damage to the prop spinner.
The most likely conclusion from the above, based upon visible evidence from the combination of pictures and AAIB statement to date, is that the port engine had stopped producing power pre impact and stop/feathering action had most likely been initiated by the crew, while the starboard engine was producing high power upon impact.
Last edited by theavionicsbloke; 11th Feb 2011 at 23:05.
Reason: correct typo