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The prop will have governing protection and overspeed protection, on top of that the engine fuel control will protect the prop from overspeeding a higher speed and also protect the core both by limiting fuel supply to combustion chamber.Quote:
Originally Posted by garrycol
But that's irrelevant if it was already stopped I guess.
Latest article in the SMH says the shaft sheared between the prop and gearbox, and Rex are removing all prop shafts and gearboxes in the same series from all of their aircraft pending the outcome of the investigation.
Early days yet but questions are being asked why he didn't divert to Canberra.
Because the passengers would have been late for their commitments in Sydney....saved the airline some money on additional flights.Quote:
Originally Posted by carlschmid2002
Gives me the .... when media/"experts" do this. There would have been a decision process between the 2 pilots and probably the company. Does a Saab 340 fly on one engine? Clearly it does. Do you expect something to just fall off your plane? Erm, no. Sorry everyone we didnt pack our crystal balls today.Quote:
Originally Posted by carlschmid2002
Well I work in Aviation Safety and I must admit I do not know all the facts but it does seem highly unusual that they didn't put it on the ground at the first opportunity. Most twins do fly quite well on one engine but they don't know what damage had occurred and they are carrying paying passengers. Unless they had a real good reason like weather, runway length or the availability of emergency services the question has to be asked.Quote:
Originally Posted by BigBlackDog
There's a whole bunch of reasons why they may have chosen not to land at the nearest suitable. CAO 20.6 follows:
3.2 The pilot in command of a multi-engine aircraft in which 1 engine fails or its rotation is stopped, may proceed to an aerodrome of his or her selection instead of the nearest suitable aerodrome if, upon consideration of all relevant factors, he or she deems such action to be safe and operationally acceptable. Relevant factors must include the following:
(a) nature of the malfunctioning and the possible mechanical difficulties which may be encountered if the flight is continued;
(aa) the nature and extent of any city, town or populous area over which the aircraft is likely to fly;
(b) availability of the inoperative engine to be used;
(c) altitude, aircraft weight, and usable fuel at the time of engine stoppage;
(d) distance to be flown coupled with the performance availability should another engine fail;
(e) relative characteristics of aerodromes available for landing;
(f) weather conditions en route and at possible landing points;
(g) air traffic congestion;
(h) type of terrain, including whether the flight is likely to be over water;
(i) familiarity of the pilot with the aerodrome to be used.
Depending on the runway/s in use, should RWY 35 have been the only operational runway on the day, manoeuvring for the approach would have taken them over some of the highest terrain in Australia. I don't know what the SAAB's single engine ceiling capability was under the conditions on the day, but it may have been lower than the lowest safe altitude to the south of Canberra. A pretty good reason for NOT going there IMO :)
I am sure their thought processes will all come out in the final report from the ATSB which will probably arrive in about 2 years by which time we will all have forgotten about this incident. An engine failure by itself would not raise any eyebrows but to actually lose a part of the aeroplane which could have done who knows what damage is certainly interesting. I was in a Black Hawk when an input model self destructed on approach to the helipad at Isurava on the Kokoda trail. This is the connection between one engine and the transmission. The engine shutdown with built in overspeed protection. It was a loud bang with associated puff of smoke and other than the indications that one engine had lost power it is very hard to fully assess the full damage. We were heavy at 20000 lbs and the pad was at 6000 ft. Luckily there was low ground and a valley to the left to regain airspeed and we turned straight to Kokoda and put it on the ground ASAP. That 10 min transit to the only possible landing point seemed like an eternity to me. We go by "Land as soon as practicable" or "Land as soon as possible" An engine failure would be the first, after a loud bang we chose the latter.
The prop is said to have landed in the Camden area. Last time I looked at a map Camden is a lot closer to Sydney than Canberra. A diversion perhaps to Bankstown might be worth considering, but the distance is not much different. Or did they mean Camden?
But the initial incident of the vibration, shutting down the engine and decending from 18,000ft to 8000ft all happened just west of Canberra, the propeller fell off some time later when over Camden.
I guess investigators will quizz the pilot as to what his logic was and we can only second guess. However irrespective of how well the aircraft flies on one engine, this is a major emergency for any twin engined aircraft. I have been in a 4 engined aircraft where one is shut down to conserve fuel but never in a twin - been in them where one has had to be shut down as a precaution (as I guess this SAAB was) but we always diverted where possible.
I guess all will become clear after the report is completed.
garry