Convair 340 (C-131D) ZS-BRV crash Pretoria, South Africa
The DC-3 was designed to maintain on one engine. This means that whatever height the engine fails at is your circuit altitude if an engine fails on take-off.
Trying to climb engine-out will quickly put you below Vmc unless you are empty. There are several accidents where this happened.
Older aircraft are not certified to current standards.
Trying to climb engine-out will quickly put you below Vmc unless you are empty. There are several accidents where this happened.
Older aircraft are not certified to current standards.
But your first two paragraphs regarding the DC-3/C-47 are sweeping statements, Eric. Goes without saying the performance varies enormously with the conditions, as well as the all-up weight. In a sea-level, UK-based public-transport operation in the late 1960s, we had to demonstrate - following an engine-failure soon after take-off - a climb to circuit height, followed by a circuit, approach and landing. The CofA-renewal air test recorded the rate-of-climb figures on each engine separately. Admittedly these were done at fairly low weights, but the expectation was that the aeroplane was flyable on one engine up to our MTOW of 28,000 lb in temperate conditions. Not that we would have wanted to put that to the test, because we preferred to nurture our old Twin Wasps...
In the same airline group at the same time, to put the above in context, the twin-jet BAC One-Elevens were operating under Performance "A" rules which - as fox niner states above - demanded a single-engine, second-segment climb-gradient of at least 2.4%.
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Your final statement is broadly correct, and probably includes the accident type.
But your first two paragraphs regarding the DC-3/C-47 are sweeping statements, Eric. Goes without saying the performance varies enormously with the conditions, as well as the all-up weight. In a sea-level, UK-based public-transport operation in the late 1960s, we had to demonstrate - following an engine-failure soon after take-off - a climb to circuit height, followed by a circuit, approach and landing. The CofA-renewal air test recorded the rate-of-climb figures on each engine separately. Admittedly these were done at fairly low weights, but the expectation was that the aeroplane was flyable on one engine up to our MTOW of 28,000 lb in temperate conditions. Not that we would have wanted to put that to the test, because we preferred to nurture our old Twin Wasps...
In the same airline group at the same time, to put the above in context, the twin-jet BAC One-Elevens were operating under Performance "A" rules which - as fox niner states above - demanded a single-engine, second-segment climb-gradient of at least 2.4%.
But your first two paragraphs regarding the DC-3/C-47 are sweeping statements, Eric. Goes without saying the performance varies enormously with the conditions, as well as the all-up weight. In a sea-level, UK-based public-transport operation in the late 1960s, we had to demonstrate - following an engine-failure soon after take-off - a climb to circuit height, followed by a circuit, approach and landing. The CofA-renewal air test recorded the rate-of-climb figures on each engine separately. Admittedly these were done at fairly low weights, but the expectation was that the aeroplane was flyable on one engine up to our MTOW of 28,000 lb in temperate conditions. Not that we would have wanted to put that to the test, because we preferred to nurture our old Twin Wasps...
In the same airline group at the same time, to put the above in context, the twin-jet BAC One-Elevens were operating under Performance "A" rules which - as fox niner states above - demanded a single-engine, second-segment climb-gradient of at least 2.4%.
Of course Performance will vary enormously with weight and density altitude. I'm not disputing that.
I'm not disputing that the DC-3 will fly on one engine - it was designed to. At lower weights it may even climb on one engine - however to the best of my knowledge this wasn't part of the original certification. That is why I used the word 'maintain' - which I believe was also used in the Douglas advertising for the type.
I have had an engine failure in the DC-3. It was cold and the density altitude was very low. With climb power on the good engine I was able to maintain altitude with a speed of 95 knots. The aircraft was well below maximum weight.
The important point is that operating these older aircraft needs to be done with the realisation that they may be certified to different standards. They may not have the Performance margins that more modern aircraft have.
Yes, I also experienced an engine failure on a C-47 Dakota with 3 tonnes of newspapers and mail on board, but it happened at F/L 70. Hence no need to climb during the diversion. Had the ILS approach through low stratus led to a go-around, however, we fully expected it to be successful.
Eric, you do not need to convince me that the certification requirements for single-engine performance on twins have risen enormously since the DC-3 was certificated in the 1930s, and again since the Convair 340 in the early 1950s. I fully agree that those inexperienced on such older types need to be made aware of that. But there is no need to exaggerate to make the point. You wrote that, in the DC-3/C-47, "Trying to climb engine-out will quickly put you below Vmc unless you are empty."
Eric, you do not need to convince me that the certification requirements for single-engine performance on twins have risen enormously since the DC-3 was certificated in the 1930s, and again since the Convair 340 in the early 1950s. I fully agree that those inexperienced on such older types need to be made aware of that. But there is no need to exaggerate to make the point. You wrote that, in the DC-3/C-47, "Trying to climb engine-out will quickly put you below Vmc unless you are empty."
One interesting observation of better modern single engine climb performance is with control zone steps. I used to think of them as step downs but was told that the steps were set by single engine climb performance. For example the steps south of Gatwick have been significantly changed in the last 20 years or so to give higher uncontrolled air space/higher steps as single engine performance is so much better.
Yes, as is the climb performance when both donks are working! Since you mention Gatwick, one of the standard departures from the westerly runway in the late 1960s (Rwy 27 in those days, since re-designated Rwy 26L) involved climbing straight ahead before a right turn to the east. The turn was to be commenced at a waypoint a certain distance west of the airfield, or passing an altitude of 1100 ft - whichever happened later. The 1100 ft was to ensure terrain clearance in the turn. All the modern aircraft were well above 1100 ft by the time they got to the waypoint. One day I was P2 on our worst-performing Dakota and, heavily-laden, we were clawing our way skywards on both engines but - having passed the waypoint by a mile or two - were still below the 1100 ft. ATC called to ask why we hadn't turned yet (this was long before transponders and Mode-C altitude read-out became compulsory), so we had to remind them about the altitude requirement.
OAP
Why do these types of threads always turn into “well here’s what I did back then and look at how good I am” discussions?
Lets stick to discussing the accidents and it’s probable causes.
Lets stick to discussing the accidents and it’s probable causes.
Last edited by B2N2; 4th Aug 2018 at 06:41.
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Of course there are those on PPRuNe who take exception to any speculative discussion of an accident - see at least one post regarding the JU-52 accident yesterday. My opinion is that we can all learn from (and perhaps even contribute to) the sum of human knowledge in the aerospace field if we are prepared to read and/or contribute with any degree of authority and honesty to such conversations. A significant, if small proportion of our speculative discussions on the possible fate of AF447 were a case in point. Once an accident report has been published, the incentive to contribute ideas is reduced.
In advance of a definitive report almost all discussion is speculative. Cut that out and you are left with photos of wreckage and mawkish expressions of sympathy to the bereaved.
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Thank you Chris. A timely reminder of the benefits of having people of your experience and knowledge being allowed to speak (i.e. post). It is not going too far to evoke the old cliche - "pearls of wisdom". (I thought the MH370 threads were being hampered by the weight of trite comment. In this case the final report begs more questions than it answers. )
There are more things in heaven and earth, Horatio,
Than are dreamt of in your philosophy.
- Hamlet (1.5.167-8), Hamlet to Horatio
There are more things in heaven and earth, Horatio,
Than are dreamt of in your philosophy.
- Hamlet (1.5.167-8), Hamlet to Horatio
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Fuel type
The fuel type (Avgas v Kerosene) actually pumped into wing during refuelling prior to this flight, is now in question.
It will of course be critical to see what the investigation finds from fuel samples taken.
I mention this because it now appears that both engines were failing / had failed, meaning the right engine was also seen on fire, before impact. That report from an experienced pilot eye witness on ground, close to the crash.
It will of course be critical to see what the investigation finds from fuel samples taken.
I mention this because it now appears that both engines were failing / had failed, meaning the right engine was also seen on fire, before impact. That report from an experienced pilot eye witness on ground, close to the crash.
Last edited by Runnymede; 8th Aug 2018 at 09:36.
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I questioned the refuelled type of fuel quite in the beginning of the thread but my posting was deleted 
Large airplanes have the risk the refueller automatically takes the Jet A truck... as are planes with "turbo" on the nacelles close to the fuel cap.
Anyway if it will show it was the reason for the crash it will be sickening for all those who got hurt.
Large airplanes have the risk the refueller automatically takes the Jet A truck... as are planes with "turbo" on the nacelles close to the fuel cap.
Anyway if it will show it was the reason for the crash it will be sickening for all those who got hurt.
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I find this bit of speculation a tad unlikely, a piston engine fed with a mixture of avgas and kerosene would trail a cloud of white smoke from both engines and a distinctive smell of partially burned kero.
This does, of course, depend on the amount of good avgas in the pipeline and on the mixture percentage in the tanks.
This does, of course, depend on the amount of good avgas in the pipeline and on the mixture percentage in the tanks.
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Happened to a DC-6 in Fairbanks. Alaska. I know a guy who was a witness to the accident.
In the above referenced accident, the guy who was there told me that as the plane took off, there were long yellow flames coming from the exhaust stacks as the plane took off. He was a mechanic for the airline, so was familiar with what a normal exhaust flame looked like on a DC-6 taking off. That said, the flames in the video appeared to be coming from under the nacelle, not out of the augmenter, which is where I'd expect an exhaust flame to be. On the other hand, running a gasoline engine on jet fuel often results in catastrophic detonation. If it blew the head off a cylinder (which is within the realm of possibility) there would be plenty of engine oil running around loose, heat and sources of ignition. I wouldn't say that the fire in the video is ruling out mis-fuelling.
In the above referenced accident, the guy who was there told me that as the plane took off, there were long yellow flames coming from the exhaust stacks as the plane took off. He was a mechanic for the airline, so was familiar with what a normal exhaust flame looked like on a DC-6 taking off. That said, the flames in the video appeared to be coming from under the nacelle, not out of the augmenter, which is where I'd expect an exhaust flame to be. On the other hand, running a gasoline engine on jet fuel often results in catastrophic detonation. If it blew the head off a cylinder (which is within the realm of possibility) there would be plenty of engine oil running around loose, heat and sources of ignition. I wouldn't say that the fire in the video is ruling out mis-fuelling.