Bearskin Crash — FEB 25, 2020 — Dryden, ON

[digits_]

The checklist seems strange as well. The response to 'Start Locks' is.........'Clear, Clean, Wing Cap On'. That means three things have been checked but none of them have anything to do with start locks.

The checklist item may seem odd to those on the outside but actually makes sense. It's a command - "I want to release the locks" your checking that there is nothing in front of you before you pull reverse power, checking the wings are free and the fuel cap is on - all before the locks are released. In other words after the response - you release the locks....it's not a check for the locks. You do them all as your looking out the window on the respective side.

As for the checklist, does checking that the fuel caps are on have anything to do with releasing the start locks. Does checking that the wings are free from contamination have anything to do with releasing the start locks.

No, it is meant as a trigger. A bit awkwardly worded, but there is some logic to it.

The missed positive torque call is the big one. Sounds like the cpt was in a bit of a rush.

[The Hammer]

First day of line training for the F/O. The captain had loads of experience on type but unfortunately didn't seem to be performing particularly well. Anyone can miss a checklist item but it is too bad that he didn't check the torques as the power was brought up. Improper blade angles can send a multi-engine aircraft off the runway very quickly(if they are asymmetric).

Torques are often your best way of discovering this. One aircraft I flew had lights to let you know when you could go into reverse, but they didn't always illuminate due to unreliable contacts. Checking for even torques could confirm if the blades had hung up or it was a light problem.

The checklist seems strange as well. The response to 'Start Locks' is.........'Clear, Clean, Wing Cap On'. That means three things have been checked but none of them have anything to do with start locks.Released might be a better response with the other response something like 'Props and Wings'.

I disagree with pretty much everything you just said.....once again Pelmet comes to the rescue - going on about stuff he knows nothing about.

The captain didn't do his job. Period. He was supposed to watch the torque as they applied initial power for takeoff and obviously didn't do that. You can make all the checklists in the world and still screw the pooch. The checklist item may seem odd to those on the outside but actually makes sense. It's a command - "I want to release the locks" your checking that there is nothing in front of you before you pull reverse power, checking the wings are free and the fuel cap is on - all before the locks are released. In other words after the response - you release the locks....it's not a check for the locks. You do them all as your looking out the window on the respective side.

Anyone with an ounce of common sense will know if their start locks did not release. First - any time the power lever is advanced that engine still on the locks will accelerate a LOT faster than the one that has been released, and second it will pull when it taxi's. Can't really blame the FO as he had never flown it before - but someone should have wondered why they have a whole lot of rudder (or joystick, or tiller) while they taxi a metro.

If you've taxied a Metro with enough power to need lots of rudder you're already in the grass. It taxi's with minimal power and it's very easy to get to runway with a prop still on the locks. Once you get it rolling initially your in beta most of the way.

I believe the checklist was fixed to address the poor wording and yes the Captain dropped the ball on this one and i think the FO is still employed there or at least was until COVID blew up the industry. First day of line indoc in Feb 2020 and COVID 3 weeks later....

[pelmet]

The checklist seems strange as well. The response to 'Start Locks' is.........'Clear, Clean, Wing Cap On'. That means three things have been checked but none of them have anything to do with start locks. Released might be a better response with the other response something like 'Props and Wings'.

I disagree with pretty much everything you just said.....once again Pelmet comes to the rescue - going on about stuff he knows nothing about.

The checklist item may seem odd to those on the outside but actually makes sense. It's a command - "I want to release the locks" your checking that there is nothing in front of you before you pull reverse power, checking the wings are free and the fuel cap is on - all before the locks are released. In other words after the response - you release the locks....it's not a check for the locks. You do them all as your looking out the window on the respective side.

The TSB wasn't happy with the checklist for the Start Locks either. Here is what they said.....

"Finding as to causes and contributing factors

The “Before Taxi” checklist did not contain a task to ensure that the start locks were removed and, as a result, the crew began taxiing unaware that the propellers were still on the locks."

As I said earlier, the response to 'Start Locks' has nothing to do with them being released. It seems to be more for checking wing contamination and checking the fuel cap.

According to the report, the checklist was modified after the accident. It would be interesting is to see what the manufacturers checklist says and what the new Perimeter checklist says for Start Locks. A lot of operators like to modify or eliminate what the manufacturer has published.

[pelmet]

The checklist seems strange as well. The response to 'Start Locks' is.........'Clear, Clean, Wing Cap On'. That means three things have been checked but none of them have anything to do with start locks. Released might be a better response with the other response something like 'Props and Wings'.

I disagree with pretty much everything you just said.....once again Pelmet comes to the rescue - going on about stuff he knows nothing about.

The checklist item may seem odd to those on the outside but actually makes sense. It's a command - "I want to release the locks" your checking that there is nothing in front of you before you pull reverse power, checking the wings are free and the fuel cap is on - all before the locks are released. In other words after the response - you release the locks....it's not a check for the locks. You do them all as your looking out the window on the respective side.

The TSB wasn't happy with the checklist for the Start Locks either. Here is what they said.....

"Finding as to causes and contributing factors

The “Before Taxi” checklist did not contain a task to ensure that the start locks were removed and, as a result, the crew began taxiing unaware that the propellers were still on the locks."

As I said earlier, the response to 'Start Locks' has nothing to do with them being released. It seems to be more for checking wing contamination and checking the fuel cap.

According to the report, the checklist was modified after the accident. It would be interesting is to see what the manufacturers checklist says and what the new Perimeter checklist says for Start Locks. A lot of operators like to modify or eliminate what the manufacturer has published.

I found a Metro checklist on the NTSB website. Click on the link below which opens up a long list of options and then click on item 31 for the Before Taxi Checklist. The fourth item is........Propeller Start Locks - Release.

https://data.ntsb.gov/Docket?ProjectID=94463

[cncpc]

The checklist seems strange as well. The response to 'Start Locks' is.........'Clear, Clean, Wing Cap On'. That means three things have been checked but none of them have anything to do with start locks. Released might be a better response with the other response something like 'Props and Wings'.

I disagree with pretty much everything you just said.....once again Pelmet comes to the rescue - going on about stuff he knows nothing about.

The checklist item may seem odd to those on the outside but actually makes sense. It's a command - "I want to release the locks" your checking that there is nothing in front of you before you pull reverse power, checking the wings are free and the fuel cap is on - all before the locks are released. In other words after the response - you release the locks....it's not a check for the locks. You do them all as your looking out the window on the respective side.

The TSB wasn't happy with the checklist for the Start Locks either. Here is what they said.....

"Finding as to causes and contributing factors

The “Before Taxi” checklist did not contain a task to ensure that the start locks were removed and, as a result, the crew began taxiing unaware that the propellers were still on the locks."

As I said earlier, the response to 'Start Locks' has nothing to do with them being released. It seems to be more for checking wing contamination and checking the fuel cap.

According to the report, the checklist was modified after the accident. It would be interesting is to see what the manufacturers checklist says and what the new Perimeter checklist says for Start Locks. A lot of operators like to modify or eliminate what the manufacturer has published.

I found a Metro checklist on the NTSB website. Click on the link below which opens up a long list of options and then click on item 31 for the Before Taxi Checklist. The fourth item is........Propeller Start Locks - Release.

https://data.ntsb.gov/Docket?ProjectID=94463

Was that a Garrett powered Caravan?

[throwaway23]

From Perimeter SA-227 Normal Checklist, Revision 9. Start Locks is now a separate check.

[cncpc]

The TSB wasn't happy with the checklist for the Start Locks either. Here is what they said.....

"Finding as to causes and contributing factors

The “Before Taxi” checklist did not contain a task to ensure that the start locks were removed and, as a result, the crew began taxiing unaware that the propellers were still on the locks."

As I said earlier, the response to 'Start Locks' has nothing to do with them being released. It seems to be more for checking wing contamination and checking the fuel cap.

According to the report, the checklist was modified after the accident. It would be interesting is to see what the manufacturers checklist says and what the new Perimeter checklist says for Start Locks. A lot of operators like to modify or eliminate what the manufacturer has published.

I found a Metro checklist on the NTSB website. Click on the link below which opens up a long list of options and then click on item 31 for the Before Taxi Checklist. The fourth item is........Propeller Start Locks - Release.

https://data.ntsb.gov/Docket?ProjectID=94463

Was that a Garrett powered Caravan?

Disregard, thought this was the eat the tail off the Otter thread.

[airway]

From Perimeter SA-227 Normal Checklist, Revision 9. Start Locks is now a separate check.

Couple of odd things on this checklist IMO. Maybe a Perimeter person could explain.

What is the difference between a "clear clean wing" and a "clean wing"?

Do you really need "Parking Brake Released" on a Before Taxi checklist?




.

[cncpc]

From Perimeter SA-227 Normal Checklist, Revision 9. Start Locks is now a separate check.

Do you really need "Parking Brake Released" on a Before Taxi checklist?

Not really. Just as well do it on the Lineups. If you get that far.

[‘Bob’]

From Perimeter SA-227 Normal Checklist, Revision 9. Start Locks is now a separate check.

Do you really need "Parking Brake Released" on a Before Taxi checklist?

Not really. Just as well do it on the Lineups. If you get that far.

Yes you do.

It could be a “killer item”.

https://www.tsb.gc.ca/eng/rapports-repo ... q0087.html

[digits_]

From Perimeter SA-227 Normal Checklist, Revision 9. Start Locks is now a separate check.

Couple of odd things on this checklist IMO. Maybe a Perimeter person could explain.

What is the difference between a "clear clean wing" and a "clean wing"?

Do you really need "Parking Brake Released" on a Before Taxi checklist?

'clear' is about the prop area, not the wing.

Another example of checklist inflation?

[airway]

Do you really need "Parking Brake Released" on a Before Taxi checklist?

Not really. Just as well do it on the Lineups. If you get that far.

Yes you do.

It could be a “killer item”.

https://www.tsb.gc.ca/eng/rapports-repo ... q0087.html

OK, I guess on the Metro it is important
Poor design if you ask me.

An article about the Metro II parking brakes in the Fairchild Facts newsletter in February 1993 stated the following:

Before taxiing or beginning the takeoff roll, ensure that parking brake is fully released. Just moving the parking brake control knob to the "OFF" position is not enough to ensure release of the brakes. As stated in the AFM, the system requires pressure be applied to the brake pedals to fully release the parking brake since some residual pressure can remain even with the knob in the "OFF" position. Taxiing and taking off with brake partially engaged can result in any or all of the following:
Increased power necessary to taxi.
Longer or MUCH longer takeoff rolls (possibly longer than available runway.)
Hot, burned or seized brake components. Possible fire in the main gear well.
Tire failure on takeoff or the next landing.
Overheated hydraulic fluid streaming overboard from the vent located near the nosewheel well.
Some make it a habit to press the brake pedals firmly to ensure that the parking brake is fully released prior to adding power and beginning to move aircraft.
For the above reasons, Metro II crews tend not trust the parking brake. The brake sometimes stays on after being released, reportedly more often in winter. The company pilots used wheel chocks instead of the parking brakes. Wheel chocks were used while the engines were started on the day of the accident. However, it could not be determined whether the crew used the parking brake between engine start and take-off.




.

[NotDirty!]

From Perimeter SA-227 Normal Checklist, Revision 9. Start Locks is now a separate check.

Couple of odd things on this checklist IMO. Maybe a Perimeter person could explain.

What is the difference between a "clear clean wing" and a "clean wing"?

Do you really need "Parking Brake Released" on a Before Taxi checklist?

'clear' is about the prop area, not the wing.

Another example of checklist inflation?

Shouldn’t you have checked that the prop area was clear before starting the engine? If it wasn’t before, it probably is now!

[digits_]

Couple of odd things on this checklist IMO. Maybe a Perimeter person could explain.

What is the difference between a "clear clean wing" and a "clean wing"?

Do you really need "Parking Brake Released" on a Before Taxi checklist?

'clear' is about the prop area, not the wing.

Another example of checklist inflation?

Shouldn’t you have checked that the prop area was clear before starting the engine? If it wasn’t before, it probably is now!

Oh, absolutely. Completely agree with you. Just explaining what is (likely) meant by the checklist item.

Checklists only ever grow, they never shrink.

[pelmet]

Couple of odd things on this checklist IMO. Maybe a Perimeter person could explain.

What is the difference between a "clear clean wing" and a "clean wing"?

Do you really need "Parking Brake Released" on a Before Taxi checklist?

'clear' is about the prop area, not the wing.

Another example of checklist inflation?

Shouldn’t you have checked that the prop area was clear before starting the engine? If it wasn’t before, it probably is now!

The checklist we are discussing is done after both engines have are running.

[BTD]

'clear' is about the prop area, not the wing.

Another example of checklist inflation?

Shouldn’t you have checked that the prop area was clear before starting the engine? If it wasn’t before, it probably is now!

The checklist we are discussing is done after both engines have are running.

When you remove the props from the start locks it is a blast of reverse and then they blow a lot more air backward compared to when they are on the locks. You want to make sure your ground crew has disconnected the GPU and cleared the area. It’s been 10 yrs but that is the gist as I remember it.

[cncpc]

Not really. Just as well do it on the Lineups. If you get that far.

Yes you do.

It could be a “killer item”.

https://www.tsb.gc.ca/eng/rapports-repo ... q0087.html

OK, I guess on the Metro it is important

It is on the Jetstream as well.

As for start locks, I remember that as being one of the last items on the Before Taxi checklist. In my last job working for someone else, I had to write up responses to at least 3 CADORS for rejected takeoffs where that item was missed, the taxi and takeoff run were carried out with the props still on the locks. That led on to another incident, not reported, where the aircraft was near V1 and the FO called Reject where the speeds were not right. The pilot doesn't reject, but slams the throttles backward over the gate, does whatever else is involved in bringing them off the locks, and then rammed the throttles forward and continued the takeoff. That raised some eyebrows.

[lownslow]

I would imagine these things could be avoided with just a tiny bit of care. With the props on the locks they cannot go into positive pitch angles so you need an awful lot of jam to get moving in the first place. All the prop (and engine) can do when you give it more power on a locked prop is to turn faster, while off the locks you should have a relatively constant idle RPM in beta (ground) mode while the blade angles change with power lever position. So when you go to taxi out, put that power on gently and listen for the RPM rise that indicates you missed something.

If in doubt a quick static run up on the button will tell you if the locks are off, a locked prop will show minimal torque and won’t be governed by the prop governor but making it that far is often an indication of being sloppy and inattentive. Maybe you’re just having a bad day or maybe that’s who you are as a person but recognizing it is the first step towards fixing it.

[bobcaygeon]

I would imagine these things could be avoided with just a tiny bit of care. With the props on the locks they cannot go into positive pitch angles so you need an awful lot of jam to get moving in the first place. All the prop (and engine) can do when you give it more power on a locked prop is to turn faster, while off the locks you should have a relatively constant idle RPM in beta (ground) mode while the blade angles change with power lever position. So when you go to taxi out, put that power on gently and listen for the RPM rise that indicates you missed something.

If in doubt a quick static run up on the button will tell you if the locks are off, a locked prop will show minimal torque and won’t be governed by the prop governor but making it that far is often an indication of being sloppy and inattentive. Maybe you’re just having a bad day or maybe that’s who you are as a person but recognizing it is the first step towards fixing it.

In a Metro unless your heavy or making an immediate hard turn it requires little power to get a Metro moving a pavement. The report says they were light. With a prop on the lock you can get about 20% torque on the gauge. I'm not a complete tool and I've done it several times especially when the engine is cold as it likes to stick and more reverse/beta is required than normal. It's easy to taxi with it "on the locks". I've flown a PT6 with prop locks and I've never had it happen on that aircraft.

It's definitely a slight weakness in the design but as we all agree it's normally easily safeguarded by ensuring proper procedures are in place and should have been is easily caught as the power levers were advanced for take-off.

[lownslow]

In a Metro unless your heavy or making an immediate hard turn it requires little power to get a Metro moving a pavement.

I don’t doubt that, those little high pressure tires look like they’d roll pretty easy. I only have about an hour of Metro time (I think it was a 23DC model if that sounds right) but I don’t recall how easy it was to get moving.

In any case, with the props locked at flat pitch you won’t see an increase in thrust until the RPM increases. In beta the RPM is controlled by the underspeed governor metering fuel flow and that governor doesn’t move above idle speed until the power lever has been advanced some way towards flight idle (it also perks up RPM past a point in reverse but that’s beside the point right now). Maybe the Metro produces enough thrust in flat pitch to roll away at idle, but either way on the locks it won’t start producing more thrust until RPM goes up because it’s effectively fixed pitch (just like a Cessna 172!) while off the locks it will start making more thrust as soon as you push the power lever forward of the gate.

Side note: Pratts and Garretts have pitch locks for very different reasons. Pratts get them in order to ensure no thrust is produced until the pilot is ready for it while Garretts lock the blades in flat pitch to relieve load off the starter and keep the hot section cooler on startup.

[digits_]

If the guy(s) didn't notice the props on the locks while setting take off power, then how would you expect them to notice the slightly different power settings for taxi