xsbank wrote:I think the oil cap is a problem - however, what killed these guys was an inability to fly on one engine. All to do with the inability to fly the aircraft at the correct speed and to compensate for assymetric thrust. It was a nice day, a steady descent, a long runway and lots of power on the remaining.
I'm not sure that is correct, although the accident report is a bit vague in terms of what actually happened. It says the props were turning at 1900rpm during the descent and neither was feathered, so they weren't "flying on one engine" (at least, not for most of the descent). When the upset happens, it just says "When power was applied, likely only to the right engine", which I assume to mean that the pilot pushed both thrust levers forward but only one engine actually increased thrust.
It's a little unclear, but my reading between the lines is that the pilot assumed both engines were working normally (as oil pressure was normal). However at the last moment when increasing power, one of the engines didn't develop any thrust and that caused the upset (being too close to the ground to recover).
It does say "If there were an indication of declining oil pressure, it would go from normal pressure to no pressure quite quickly", so perhaps the low oil pressure checklist which says to "reduce power and continue flight" when oil pressure is 40-80 psi isn't the best thing to do.
You're right there's some ambiguity in how it was written, however I read it that only the right engine had the throttle pushed forward. There was no conclusion of any problems with the left engine in the report. With respect to the cause, they fell below Vref seemingly because they were unfamiliar with the need to add 10 kts in a Low Oil scenario. I wonder what the circumstances were at the time he applied power, was it a quick application of full power, or a gradual one to feel how the aircraft yawed.
In any event as with most accidents there was chain with many links. If they had checked out the oil leak ...
I talked to a few of the employees shortly after TSB held a meeting with them advising them of what they found. The pilots think that the left yaw was caused by a firewalling or very rapid advancement of the throttles. Apparently that KA 100's with these mods done to it is known to roll over to the left if the power is advanced too rapidly.
Why the captain allowed the aircraft to slow so much is not known.
Reminds me of the failed landing light accident , where a perfectly serviceable large plane ran out of fuel whilst the 3 man crew was fiddling with a gear lamp ,,,NOTHING to see here folks PILOT FOOLISH ERROR and the "fraternity" ( like the cops) gleefully trying to find a "reason" why such superior beings were let down by the brute beast of a plane ,,,,,,,,
boeingboy wrote:I talked to a few of the employees shortly after TSB held a meeting with them advising them of what they found. The pilots think that the left yaw was caused by a firewalling or very rapid advancement of the throttles. Apparently that KA 100's with these mods done to it is known to roll over to the left if the power is advanced too rapidly.
Seems like something that could happen to many different aircraft but I have never heard of mods on the aircraft making it more likely to do so. Usually the mods are by Raisbeck. We had dual aft body strakes, wing fences and "quiet" four bladed props along with a belly pod. The aircraft was quite unstable in roll and if you did not pay attention in cruise, you could find yourself well off proper heading. I saw one guy 90° off course while chatting in IMC. No autopilot of course. Good thing the airspace was uncontrolled.
I watched the TSB news conference when the report was released, and the lead investigator said something along the lines of "the Raisbeck mod, with the propellor disced and the power at idle, produces so much drag that it's like having -300 ft/lbs of torque". It was actually worse to have the engine running than to shut it down and feather the prop. He also phrased the portion about advancing the power on one side a bit differently than the report; I can't remember exactly what he said, but he made it sound like the pilot had kept the left engine at idle to keep the oil pressure down and only advanced the right power lever. The combination of high torque on the right and negative torque on the left resulted in a much higher minimum control speed than published and caused a VMC roll.
Edit: Here's a source from the report regarding the 300 ft/lbs of drag: "However, the propeller manufacturer calculated the drag produced by the aircraft’s 4-bladed propeller, turning at about 1900 rpm, to be about 300 pounds." And here's one implying that the left engine was kept at idle throughout the descent without the prop feathered: "oth propellers maintained about 1900 rpm. An engine igniter was on throughout the descent [indicating a power setting below 425 ft/lbs], and continued through to the upset."
crazy_aviator wrote:Reminds me of the failed landing light accident , where a perfectly serviceable large plane ran out of fuel whilst the 3 man crew was fiddling with a gear lamp ,,,NOTHING to see here folks PILOT FOOLISH ERROR and the "fraternity" ( like the cops) gleefully trying to find a "reason" why such superior beings were let down by the brute beast of a plane ,,,,,,,,
Good point, I couldn't help but chuckle at some of the speculation in this thread. Am glad the TSB employs a tad more logic in their investigation than the members of Avcanada.
I marvel at the idiousy of several posts here. It was not a big bird nor the supposed instability of the Be-100 with the raisebeck mod that caused this crash. Loss of situational awareness much like the Asianic 777 accident was the direct cause. Letting the speed fall behind the curve often has a deadly outcome especially close to the ground. The effect of 1 engine at idle and prop fine and the other at some level of power should be demonstrated at altitude during training. Its an eye opening exercise. Especially on this airceaft. Just one thing more. A 90 degree heading drift is NOT the fault of any aircraft Mod. Just poor airmanship. Nothing more, nothing less. Stop the stupid excuses.
The aircraft was configured in a way that didn't meet the definition of VMC, which meant the speed at which they lost control was unpublished and unpredictable. Based on what they knew and how they'd been trained, the pilots had no reason to assume they would lose control for another ten knots. Even though they were five knots below VREF they expected to have another ten knots of buffer, and began correcting once they realized they were slow. There was no reason for them to expect an application of power would cause a loss of control.
Diadem wrote:I watched the TSB news conference when the report was released, and the lead investigator said something along the lines of "the Raisbeck mod, with the propellor disced and the power at idle, produces so much drag that it's like having -300 ft/lbs of torque". It was actually worse to have the engine running than to shut it down and feather the prop. He also phrased the portion about advancing the power on one side a bit differently than the report; I can't remember exactly what he said, but he made it sound like the pilot had kept the left engine at idle to keep the oil pressure down and only advanced the right power lever. The combination of high torque on the right and negative torque on the left resulted in a much higher minimum control speed than published and caused a VMC roll.
Edit: Here's a source from the report regarding the 300 ft/lbs of drag: "However, the propeller manufacturer calculated the drag produced by the aircraft’s 4-bladed propeller, turning at about 1900 rpm, to be about 300 pounds." And here's one implying that the left engine was kept at idle throughout the descent without the prop feathered: "oth propellers maintained about 1900 rpm. An engine igniter was on throughout the descent [indicating a power setting below 425 ft/lbs], and continued through to the upset."
I have not had time to read the report. However, I can tell you that leaving an engine on a turboprop unfeathered at idle instead of shutting it down is or at least potentially is bad news(in a performance limited situation such as maintaining high altitude or landing configuration) and this should not be done without careful consideration. It leads to a high drag situation that we all learned about in our multi-engine training about a windmilling propeller and all the drag associated with it. Even though the engine is at idle, there is still drag and it makes sense that if they had the four-blade Raisbeck "Quiet Turbofan" propellers installed that there would be even more drag than with the original three-bladed props.
Perhaps there is an assumption on occasion that if the engine is still running that there is not a significant amount of drag but there is. This information should be known by all pilots flying these sorts of aircraft. It is obvious if you think about it but perhaps we don't think about it and we don't normally train this specific scenario so in the heat of action, the consequences of such an action may not be fully considered. Likely, the engine was left running as it was considered to be useful and safer, but in reality based on how it was operated, it became a liability and a causal factor in the accident.
So what can we as pilots do to prevent such a scenario or other similar scenarios from happening. There are so many possible "Gotcha's" out there and we just won't be given each one of them as an example during our training.
My suggestion...read as many accident reports as possible. I have read hundreds of them and continue to do so. There are so many available on the internet nowadays from various safety boards.
Therefore....I have encountered the scenario that these King Air guys encountered. Where? In an accident report about a Saab 340 in the Netherlands in 1990 that made me realize that it is risky to just keep one engine like this at idle and better to just feather it (assuming is not needed for other reasons such as terrain clearance) and then continue on. No instructor on aircraft ever detailed the consequences of leaving an engine running unfeathered at low power on approach. We always just shut it down right away in training. But frequently, the real world is quite different than the standard training procedure that we seem to encounter over and over again.
It reminds me of that Air France situation over the Atlantic where they raised the nose so high after losing their airspeed. No one ever specifically emphasized to me in jet training how bad it is to be at such a high pitch attitude(more than 10°)like they went to at cruise altitude. Perhaps the instructors will say that it is obvious but there are thousand upon thousands of jet pilots out there and there are so many other things to study that this fact might fall by the wayside for a few when things fall apart. But, I had read about this being bad on technical forums(and AvCanada can be a great source of info) and of course it is obvious when you think about it, but it is best to consider it for the first time in your armchair. Therefore, you lose your airspeed, maybe just hold your pitch attitude or lower slightly to make sure you don't stall and then deal with the issue at hand.
Bottom line, you are on your own when it comes to really improving your knowledge about flight operations and need to read as much as you can as the training world won't and can't give you each and every possible scenario.
Flight KL433 took off from Amsterdam runway 24 at 14:19 for a 1h18min flight to Cardiff. At 14:30 the flight passed FL165, climbing to FL200 when the Master Warning was triggered by the no. 2 engine oil pressure light. The Master Warning was reset and the captain retarded the no. 2 engine power lever slowly to flight idle, causing the engine torque to decrease from 78% to 10%. Retarding the power lever is not part of the Emergency Checklist (ECL) procedure. Possibly this was done to prevent damage to the right-hand engine. The ECL Engine Oil Pressure Low procedure was then started. The ECL states that the engine must be shut down if the oil pressure warning light is on and oil pressure below 30psi. If the warning light is on and the engine oil pressure is above 30psi, normal operation should be continued. As the no. 2 engine pressure was above 50psi, both flight crew members agreed normal operation should be continued. The captain didn't want to continue to Cardiff and elected to return to Amsterdam. At 14:33 Amsterdam Radar was contacted with a PAN-call and a request to maintain FL160 and return to Amsterdam. One minute later a clearance was received to descend to FL070. KL433 was offered a straight in approach for either runway 06 or runway 01R. The captain decided to use runway 06 and was cleared to descend to 2000 feet. Landing clearance was given at 14:42 and one minute later the ILS localizer and glide slope were intercepted. The captain, not realising the consequences of flying with one engine in flight idle and was not able to anticipate correctly on the airspeed variations which resulted in an approach not stabilized in power, airspeed and pitch during the final approach. The speed had decreased to 115 knots and the crew reacted by applying an aggressive increase in torque (from 40% to 65%) with limited corrections for asymmetry. This placed the aircraft to the right of the extended centreline at an altitude of 90 feet. At 14:45:53 the captain called for a go-around and no. 1 engine torque was set at 98% with the no. 2 engine remaining at flight idle. Flaps were set at 7deg and the gear was retracted. The aircraft rolled right and pitched up to a maximum of 12deg. The stall warning system activated as the airspeed decreased and continued until impact. The Saab struck the ground with an approx. 80deg right bank and broke up.
PROBABLE CAUSES: "Inadequate use of the flight controls during an asymmetric go around resulting in loss of control.
Contributing factors: Insufficient understanding of the flight crew of the SAAB 340B engine oil system; lack of awareness of the consequences of an aircraft configuration with one engine in flight idle; poor crew resource management."
If you have an engine operating at idle and you need it, then use it. Perhaps mention this during the landing briefing if you decide to leave the engine running at idle. "If we encounter any control issues, I will add power on the bad engine as it is still operating, it just has a leak, that's all." It may be obvious but if it was briefed, it is more likely to be considered when suddenly there is a problem. Control is more important than wear and tear on the problem engine.
Also, if you decide to leave the bad engine at idle on approach, is there any reason to attempt to be at Vref on approach instead of carrying some extra speed when landing on a very long runway like they had in YVR.
Diadem wrote:The aircraft was configured in a way that didn't meet the definition of VMC, which meant the speed at which they lost control was unpublished and unpredictable. Based on what they knew and how they'd been trained, the pilots had no reason to assume they would lose control for another ten knots. Even though they were five knots below VREF they expected to have another ten knots of buffer, and began correcting once they realized they were slow. There was no reason for them to expect an application of power would cause a loss of control.
Not checking the puddle of oil under the engine after taxiing it to another location is a questionable action. It has been a long time since I flew a PT-6 operated aircraft but it seems to me that while some oil drips are normal on the bottom cowl(along with many other turbine engines) a puddle is something to be looked into. Unfortunately, the report does not say how big this puddle was.
The crew didn't check the oil cap on the walkaround but we never did either as it was not easy to remove the cowl or access it cap however it was done. I don't know to this day how to check the oil on a King Air(maybe I should). And I seem to remember that you had to be quite cautious about making sure that those cowls were latched properly and that this was another thing that could be easily missed(an unsecured cowl). Apparently someone in our company did so with a company exec on board. Not sure how much the cowl or cowl(s) opened on that particular flight but I bet the bigwig wasn't impressed. Seem to remember lines painted on the cowl and the fasteners to show proper alignment but somehow you could still be fooled into thinking they were secure when they were not....or so I was told.
Maybe some experience King Air guys can confirm. I was only on it for a short period of time.
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Last edited by pelmet on Sat Aug 03, 2013 8:07 am, edited 1 time in total.
Rudy wrote:This is my worst nightmare. I once left home and drove back to the airport in the middle of the night because I couldn't specifically remember double checking the oil cap was secure.
No you do not need to remove the cowls to check the oil. A convenient quick latch door is for that purpose. I find it odd that at least in pelmet's case a thorough walk around pointing out the location of basic service items wasn't included. Wasn't his fault. Who's doing the training and what's the company culture like that doesn't demand that? They do that for you when you first get your car from a dealership.
Not checking the puddle of oil under the engine after taxiing it to another location is a questionable action.
Are there any no-go drains on the King Air? There were 5 drains on the underside of the cowling of the F-27. If there was anything dripping out of any of them, it was no-go till it was investigated/corrected.
MUSKEG wrote:No you do not need to remove the cowls to check the oil. A convenient quick latch door is for that purpose. I find it odd that at least in pelmet's case a thorough walk around pointing out the location of basic service items wasn't included. Wasn't his fault. Who's doing the training and what's the company culture like that doesn't demand that? They do that for you when you first get your car from a dealership.
I have flown 9 different types of turbine powered aircraft in my career so far with 6 different types of engines. In all 9 cases, oil cap security was not checked on the walkaround except on one aircraft type when I was temporarily deployed to a different base where they were doing this. The only time I ever heard about an oil cap improperly secured was at this base where pilots were to check the oil level in which case, it was the co-pilot who created the problem(or maybe the company policy). That being said, doing just a check for the security of the cap instead of actually checking oil level may make sense but it doesn't seem to be a standard in the turbine world in my experience.
In reality, it is difficult to reach the oil cap on many if not most airline aircraft.
Rudy wrote:This is my worst nightmare. I once left home and drove back to the airport in the middle of the night because I couldn't specifically remember double checking the oil cap was secure.
Shit.....I've done that.
yup me too.
I am a little taken a back that there may be pilots out there that don't know how to check oil and make sure the cap is secure and then the cowling. Its not a big scary monster folks.... Just an oil cap and a cowling.
Edit: on a pt6 type turbine that is.
Not checking the puddle of oil under the engine after taxiing it to another location is a questionable action.
Are there any no-go drains on the King Air? There were 5 drains on the underside of the cowling of the F-27. If there was anything dripping out of any of them, it was no-go till it was investigated/corrected.
Don't remember the term no-go drains. There were drains designed into the engine. Originally on shutdown, a bunch of fuel would pour out of the bottom of the engine(or so I was told) but the environmentalists didn't like it so a "EPA" drain(I guess named after the Environmental Protection Agency were installed to keep the fuel from spilling out. Uses an accumulator to discharge air into the manifold and nozzles somehow.
Actually, if you flew an F-27 with those old Darts, they seemed to be the ones with the most oil leaking from them. I'm surprised you ever got going anywhere .
Just to clear up the point on access to the oil dipstick. The following does not apply to Garretts.
On 100s and older 90s, you have to open the cowl in order to check the oil. On all other King Air models a small latched door was installed in the cowl in order to check the oil. I've never left the small door unlatched but I can't imagine it being a problem.
Opening the older cowls is problematic. Once you open it you have to walk around to the opposite side, push it closed, walk back around to the latch side, and latch it. It's basically designed to make it as easy as possible to walk away without the cowl being latched, but it's easy to get at the oil dipstick.
Anyone under 6'6" checking the oil on a King Air with the new doors without a stool is asking for trouble. You can do it by feel, you can run your finger around the rim, but it's not foolproof. If the pilots are checking the oil, they should be carrying a plastic stool in the aircraft.
I have several thousand hours on be100 including serial number 003. I never came across what you describe on 100/90 cowls. All had a small door to both check and fill the oil. Yes a ladder or step up was required to allow you to see what you were doing.
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