NT Air King Air Accident - Pilot Discussion Thread

[cdnpilot77]

I got hit with a missile once....

How many people here can start a paragraph like this

[Kingairdriver]

Just a couple of 100 points
1 Some 100's have oil preasure lights, I flown ones with after market ones.
2 If oil preasure is lost the propeller should feather

[cncpc]

It was an oil leak that initiated the turnaround, with some passengers wanting to go on to Kelowna. Nothing about a fire in the engine compartment. I'm sure that would have been an emergency call.

There is a story in the Sun. Video from a passenger.

[nightguy]

I have a lot of 100 time... the oil cap being loose or undone is a very dangerous issue. In the event of loss of oil pressure a PT6 has been clocked by beech to stay "onspeed" or un-feathered for up to 90 min. At the 90 min point the test was ended. Should the aircraft slow down it should start to feather ( sorry cant say a number that it would happen at). For all the good things about the PT6 there are still some things that can make it a killer. I have lost a few friends now to the 100... and as I said I have a lot of time on it but maybe the time has come to stop fly this old bird. Given the same loss of oil pressure and a fine prop on a 200 ... I think the old 200 would have flown out of this 9 times out of 10.

So sorry to the family and friends. And all the best to the guys at NTB. Coming from Borek not long ago I know how you all feel.

[~Hollywood~]

One of the survivors tells her story.......

http://www.vancouversun.com/Anatomy+pla ... story.html

[boeingboy]

I'm sorrey - but that woman is a bimbo. There is so much wrong in that it's not funny.

Mind you - that happens in every aviation incident. Some ding-dong thinks they know everything when really - they can't tell the nose of the plane from the tail.

[cncpc]

I'm sorrey - but that woman is a bimbo. There is so much wrong in that it's not funny.

Mind you - that happens in every aviation incident. Some ding-dong thinks they know everything when really - they can't tell the nose of the plane from the tail.

The problem is probably the journalist. Yearwood's comment doesn't look good.

[cncpc]

I think the old 200 would have flown out of this 9 times out of 10.

Flown out of what, Nightguy. What was it in? It had an oil leak.

[KK7]

I haven't flown a 100, but I have flown various types of PT6 engines for quite some time. With complete loss of oil pressure, the prop will go to feather, but not until the pressure is quite low. Generally you will be dealing with the loss of oil pressure long before the prop goes to feather (unless you're hit with a missile and lose all pressure right away).

If there is a steady loss of oil pressure and the feather is not already in feather, the prop will not suddenly go to feather. It will either start transitioning to a courser pitch, or what can happen is oil pressure fluctuations with the last bit of oil remaining in the engine will cause the prop to cycle in and out of feather repeatedly until all oil pressure is lost, the prop is put into feather or the engine is shut down. I would imagine if this happened on short final at a slow approach speed, this would cause a serious controllability issues. Post crash fire probably not due to an existing fire, but because this happened soon after departure they still no doubt had a lot of fuel on board.

[KISS_MY_TCAS]

KK7, great post. I was losing hope at the amount of misinformation being spread about what happens to a PT6 when it loses oil pressure. I can tell you, the pressure will not even start to fluctuate until the oil level drops to about 6-7 quarts which is roughly half of the engines capacity. I hope training captains and ground school instructors are taking note, this looks like an excellent scenario to be taught.

Nightguy, for someone who claims to have lots of King Air time, you should know better. Just because you read it in a magazine is no excuse for not understanding your machine. Spreading the word like gospel only makes it worse for those coming up after you.

[55+]

I have a background on BE 90/A100/200 (4000+ hrs) and it has happened when oil caps are not securely tightened oil will leak or even piss out depending. It can be gradual with pressure indications and fluctuations prop rpm. But you will know there is an issue. Personally I would have shut the engine down (with appropriate checklist procedures) at altitude, returned to destination configured for a single engine landing. I will speculate here their engine quit on short final, initially unfeathered and with 7 pax, 2 crew and good load of fuel. In this situation an A100 with that 4 blade propeller is going to be a handful, even for the most experienced.
I had an unsecured oil cap on a BE-A100 a few years back but thankfully for me, it was an uneventful single engine landing.

[180]

First of all, my sincere condolences to the pilot's wife and baby, family, friends, and co-workers at N.T. And thoughts and prayers for the co-pilot and other passengers who are suffering in a bad way right now. It sends shivers down my spine imagining the poor guys stuck in the fire...so terrifying and awful, every pilot's worst nightmare.

I'm not 100% on these discussion threads starting up so soon after a tragedy; it seems like there should be a period of mourning and respect first, although I appreciate a pilot's need to know and understand, and I guess the educational value and exchange of knowledge validates it. So I'll continue with my thoughts:

We've all flown machines with fluctuating/erratic gauges, and it's easy to understand how a high time turbine guy who has thousands of hours behind or beside one or a couple of trusty P&W's would probably think indication error first, real problem second, as these engines are so very reliable.

I'm not speculating on this particular accident, but perhaps a good rule of thumb for all of us is to treat any oil pressure fluctuation/loss in a P&W as a real problem first, and as an indication problem second. And in the event of any decrease in oil pressure, land ASAP at the nearest suitable aerodrome.

I also can understand how an experienced company man would want to land his machine with an issue at the most convenient location for a specific company's maintenance (like a machine based and maintained out of Calgary that has an issue Westbound over Banff might feel a "duty" to limp the plane back to Calgary where the mechanics are waiting inside a heated hangar with tool and parts at an arms reach rather than stranding the machine and passengers in Springbank) and I think this is where chief pilots, training captains and owners have to stand up and let their guys know it's not only OK, but it is preferred by them to first and foremost land at the closest/safest airport and worry about the passenger's and mechanic's convenience second.

Again, I am not speculating on this terrible tragedy or on NT's SOP's. I'm just sharing some thoughts that might be in everyone's best interest to think about, that might save a life in the future, and that might spark up some new/fresh discussion in the manager's meetings in the next few days or weeks.

There but for the grace of God go most of us...

[Road Trip]

I haven't flown a 100, but I have flown various types of PT6 engines for quite some time. With complete loss of oil pressure, the prop will go to feather, but not until the pressure is quite low. Generally you will be dealing with the loss of oil pressure long before the prop goes to feather (unless you're hit with a missile and lose all pressure right away).

If there is a steady loss of oil pressure and the feather is not already in feather, the prop will not suddenly go to feather. It will either start transitioning to a courser pitch, or what can happen is oil pressure fluctuations with the last bit of oil remaining in the engine will cause the prop to cycle in and out of feather repeatedly until all oil pressure is lost, the prop is put into feather or the engine is shut down. I would imagine if this happened on short final at a slow approach speed, this would cause a serious controllability issues. Post crash fire probably not due to an existing fire, but because this happened soon after departure they still no doubt had a lot of fuel on board.

This is all fine but doesn't answer a number of questions.

One if this was actually the case why didn't they shut down the engine at altitude, instead risking losing it on short final and or risk causing extensive damage to the engine from being run short on oil?

Two why did they not request / accept the offer of emergency equipment? The last offer was on clearance to land. Given the description above they should have been seeing signs by then that this might be a serious issue.

Three with a gradual loss of oil pressure leading to a gradual feather wouldn't this make the engine failure a relatively slow and predictable event and as such easily dealt with?

Four I've never been to sim but some of my friends and colleges have and everyone talks about the engine failure while on final. This seems like a commonly practiced event for which both pilots should be easily able to handle. Further knowing there is an issue with the engine and anticipating a possible failure should have made them both even more ready to respond and keep control.

From what is described by all witness accounts the engine failure seemed very abrupt causing a sever swerve to the left. That doesn't match with a gradual loss in oil pressure. It matches more with a sudden loss of an engine for which they weren't able to fully predict might fail.

What could have happened that caused them to a) suspect there was a problem warranting a return to the airport, b) made them not want to request emergency services c) cause an abrupt engine failure for which they weren't fully prepared for?

Lots of stuff not adding up but the CVR will answer all these questions within a week or so until then I wouldn’t put any credit into any reports from passengers considering I’ve heard pilots giving all sorts of pacifying reasons for returning to an airport.

[RatherBeFlying]

Stall does not seem to be the case here; so, I see two mechanical possibilities for the wing drop on short final:

1. Prop bearing seizure, but you would like to think loss of oil pressure would have initiated autofeather well before that (assuming that going into feather on short final would be manageable).

2. Prop going into ground fine pitch or beta -- a suspected cause of the Luxair 9462 loss. In the Luxair case, the aircraft was behaving normally until the loss of control at low level.

So if you have an oil pressure problem on a PT-6:

Would you feather as a precaution?

Would you spiral down to the airport below you even if you are at a good altitude for a normal approach to your departure airport?

This crew did not know the exact problem in the engine and it will take the TSB some time to figure it out.

The Air Transat crew that, even after contacting maintenance at base, did not figure out the low oil temperature indication on one of their engines until they had a double flameout was in the same position even though they had considerably more time and a lot more luck.

[ex-NWT]

Many years ago two of the companies I worked for each lost a turbo prop aircraft that had an engine oil problem.
Engine power was reduced to idle and both aircraft ended up with airspeed below Vmca on short final and didn't recover.

[KK7]

With my experience with the PT6 engine, it is an extremely reliable engine, and 9 out of 10 times something that looks bad on the gauge has been a problem with the gauge/transmitter/wiring to that gauge. I think this can lead to a complacency for when a real problem happens.

In general the gauges you have for each engine is Torque, Prop RPM (Np), Inter Turbine Temperature (ITT or T5), Gas Generator Speed (Ng), Fuel Flow, Oil Pressure and Oil Temperature. For the first 5 indicators that I listed (Torque, Np, T5, Ng and FF), if something isn't right and it's a real indication problem you will see the problems on the other respective gauges, you may hear an unexpected change and notice a change in aircraft performance. If only one of these gauges is showing something wonky, and the remaining gauges are normal and everything else seems fine, it's likely an indicator problem, or another symptom will show soon to indicate a problem. Oil temperature and oil pressure will not directly affect your engine's performance. Temperature can rise or drop, and if everything else is looking normal on the engine, chances are it is an indication problem.

In my opinion, the one gauge to be really cautious about is the oil pressure gauge. Yes the indicator can fail, but a dropping oil pressure can indicate something bad coming and it may or may not be gradual. As was mentioned, the PT6 can run on nearly no oil at all, including keeping the prop out of feather. Once you run out of oil, the few splashes that remain may make your prop cycle in and out of feather and it may start with very little warning. You may think the engine is still running fine with an oil pressure indication on short final, then suddenly a large reduction of drag on one side followed by the pitch going back to fine and producing a lot of drag will cause a great deal of yaw and bank on a twin engine aircraft. With enough power going to the engine, the prop going from fine to full feather can make an aircraft jump the brakes when parked on the ground.

What you do about an engine with an oil indication problem depends on whether you need that engine or not. If I was in a C208B I'd leave that engine running for as long as I need to to get me to a safe place to land. If I'm in a twin and I need to climb or if it's too dangerous to descend to my single engine ceiling, I'll leave it running. If I don't need that engine, I'll shut it down not only to save the engine, but to get myself stabilized with the engine out instead of it quitting at an unexpected time during some critical phase of flight. Fortunately my airplane has 4 PT6 engines on it, so usually the safer bet is to shut'er down and figure it out on the ground. But if you're going to leave it running, prepare for the worst to happen at the worst possible time. Get ready for that yaw and sudden loss of power.

I'm only saying all of this in pure speculation. None of us have any idea what happened on final to Vancouver, maybe it was related to their oil pressure problems, maybe it was unrelated, maybe they made an error. But until there is strong evidence to suggest otherwise, I prefer to assume my counterparts performed their duties professionally to the very end, and they did everything they could within their abilities to prevent such a catastrophe.

[cncpc]

First of all, my sincere condolences to the pilot's wife and baby, family, friends, and co-workers at N.T. And thoughts and prayers for the co-pilot and other passengers who are suffering in a bad way right now. It sends shivers down my spine imagining the poor guys stuck in the fire...so terrifying and awful, every pilot's worst nightmare.

I'm not 100% on these discussion threads starting up so soon after a tragedy; it seems like there should be a period of mourning and respect first, although I appreciate a pilot's need to know and understand, and I guess the educational value and exchange of knowledge validates it. So I'll continue with my thoughts:

We've all flown machines with fluctuating/erratic gauges, and it's easy to understand how a high time turbine guy who has thousands of hours behind or beside one or a couple of trusty P&W's would probably think indication error first, real problem second, as these engines are so very reliable.

I'm not speculating on this particular accident, but perhaps a good rule of thumb for all of us is to treat any oil pressure fluctuation/loss in a P&W as a real problem first, and as an indication problem second. And in the event of any decrease in oil pressure, land ASAP at the nearest suitable aerodrome.

I also can understand how an experienced company man would want to land his machine with an issue at the most convenient location for a specific company's maintenance (like a machine based and maintained out of Calgary that has an issue Westbound over Banff might feel a "duty" to limp the plane back to Calgary where the mechanics are waiting inside a heated hangar with tool and parts at an arms reach rather than stranding the machine and passengers in Springbank) and I think this is where chief pilots, training captains and owners have to stand up and let their guys know it's not only OK, but it is preferred by them to first and foremost land at the closest/safest airport and worry about the passenger's and mechanic's convenience second.

Again, I am not speculating on this terrible tragedy or on NT's SOP's. I'm just sharing some thoughts that might be in everyone's best interest to think about, that might save a life in the future, and that might spark up some new/fresh discussion in the manager's meetings in the next few days or weeks.

There but for the grace of God go most of us...

A wonderful post with great balance and insight. You have everything that is in issue here and particularly that one bit that I didn't want to say, as I know NTAir is a first class company and the way I may have put it would be taken wrong, but you have said it just the right way.

I don't see any evidence that this was a gauge problem. The captain told the passengers there was a small oil leak, which implies that the problem was identified visually. The decision was made to return to Vancouver. Why that was, we don't yet know, but there were aircraft to company communications, we do know that. Both Pitt Meadows and Abbotsford have emergency equipment, and if an emergency was so imminent that a weighing of where the best emergency equipment was available was necessary, then Abbotsford was the better choice and Vancouver the worst.

I think it would be speculation to say that the dangerous problem which did develop was not related to the oil leak. I'm not sure of the mechanics, and I defer to the great expertise on these type of engines and systems in this thread. What should come into the analysis is that the longer the aircraft flew, the closer the approach of danger. When the problem was first detected, a timetable came into play and there was x amount of time before a serious problem would manifest itself. That x amount of time seems to have expired about 900 meters short of 26 or slightly before that. The time to Abbotsford or Pitt Meadows would have been significantly less than x.

I don't fly turboprops but I do have a question for those that do. I know there is some type of prop setting checklist item on final. In the context of oil running low or exhausted, would going to this setting have resulted in an asymmetric thrust condition and the resultant apparently uncontrollable yaw?

We had this discussion in the Resolute thread(s) and I maintain that early discussion as to analysis and causes when carried out in a respectful and intelligent way is entirely appropriate. If some young pilot who reads this today has an oil leak in a King Air or any similar aircraft tomorrow, I am sure he or she will be better equipped to make decisions that result in the best outcomes for all who depend on his or her decisions.

Thank you once again for a great post.

[KK7]

I don't fly turboprops but I do have a question for those that do. I know there is some type of prop setting checklist item on final. In the context of oil running low or exhausted, would going to this setting have resulted in an asymmetric thrust condition and the resultant apparently uncontrollable yaw?

That is an interesting discussion point, but I would be surprised if this caused any serious problem.

In normal conditions, for most types of aircraft and operations the prop levers are advanced to max RPM or full fine from a cruise setting when on final. AFAIK, most operators require some sort of stabilized approach before the aircraft reaches below 500' AGL on final. That means the prop RPM should be advanced at or prior to this point.

In the PT6 advancing the the prop levers to maximum RPM opens a valve to allow more oil pressure into the prop hub to force the prop blades to fine, but the quantity of this oil is not a substantial amount. However if they had both engines running and the the RPM was left at a cruise setting until final, then they advanced the prop levers to max RPM and at that particular time they ran out of oil or something happened to one of the engines, it would only exacerbate the situation. Whether it would be the direct cause I don't know, but my feeling would be no.

I don't know what the procedure is in the King Air, but generally when there is a problem with the engines the prop levers are advanced to maximum RPM early on as if maximum power is ever required, the prop RPM must be at it's maximum setting. I suppose if they felt the problem wasn't serious, they wouldn't change the prop RPM until on final.

[ahramin]

If the quotes are accurate this Cross person is a complete wingnut. What a load of make believe.

This part though:

The other fire truck used its reinforced bumper to crash through a runway gate.

I'm so glad to hear that thinking is still demonstrated in some professions. Great big A+ to the fire crew in that truck.

[Doc]

XXXXXXX