Monday, January 25, 2010

I'm very grateful that I'm in a job where I don't have to put a price on safety, because sometimes safety is incredibly expensive. Allow me to elaborate...

We flew west today for a whole long while, and on the way west we stopped in Omaha Nebraska to clear US Customs. The Customs people were friendly and quick and that part was great, but the part that wasn't too hot was the weather.

It was overcast and snowing today in Omaha, and we ended up picking up some ice. Not quite the "Can't see out the windshield" kind we had a couple of weeks ago (scroll down a couple of posts for that story), but any ice is too much ice on a plane, so we had to remove it before continuing our journey westbound.

When deicing in North America, there are generally 4 different types of fluid used, conveniently named Type I, II, III and IV.

Type I is a de-ice fluid, meaning it's used to remove ice that has already accumulated on the plane. It's a mixture of 90% glycol (alcohol) and 10% water which is heated to about 90 degrees Celsius before being sprayed on the plane. It's usually colored bright orange, like in the video I attached to this post. Type I is great for removing ice, but it doesn't provide a very long period of protection from re-icing after it's applied.

Type IV is the most commonly used anti-ice fluid and is normally colored green. It's a mixture of glycol and a thickener, usually vegetable oil. The thickener prevents the glycol from dripping off the wings after the fluid is sprayed on, which provides decent protection for a while if it's snowing outside etc. The stuff is supposed to stick like glue to the wings until you are doing about a hundred miles an hour down the runway, when it's supposed to drip off and leave no trace. Oh, and as a random observation, it tastes terrible.

Anyway, you are less likely to come across the other two types of fluid, but I'll include them here for the sake of completeness:

Type II is an anti-ice fluid, meaning it's put on to prevent ice from forming on the wings it's snowing outside, etc. It's being phased out in favor of Type IV, which is more effective.

Type III is an anti-ice fluid but it's hardly used any more, if at all - it was designed for smaller commuter aircraft but it turns out that Type IV is equally effective, so type III became irrelevant.

So how do we know what fluids to apply in what situations?

In Canada, Transport Canada publishes an updated manual called the HOT guidelines (not nearly as fun as it sounds), which lists the length of time you can expect your de-icing or anti-icing fluid to provide protection.

Anyway, if the airplane is just covered in ice but the skies are clear then we generally would only use Type I, but if it was snowing or freezingly raining then we'd add a coat of Type IV for added protection.

For example, if it was -5c with freezing fog at the airport we wanted to depart from, Type I fluid might give us up to 13 minutes of protection against refreezing, but if we added a coat of Type IV, it would provide us up to 80 minutes of protection against refreezing.

At large airports during bad-weather days there can be long lines of aircraft waiting to depart, so the longer you have protection, the greater your chances of being cleared for takeoff while your de-ice and anti-ice fluids are still working. If the lineup is too long and/or the precipitation is too bad (freezing rain, etc) then it's entirely possible the aircraft will have to pull out of the departure lineup and go back to get de-iced again.

And now, here's some of this stuff being put to use in real life:

We only took Type I de-ice fluid because it wasn't actually snowing in Omaha, so we didn't need to worry about any additional ice while we were taxiing for departure. In the video it looks snowy, but that's just snow blowing around the ramp.

In the 5 minutes it took to de-ice us this morning, they used 42 gallons (158L) of heated Type I Oh, did I mention it's $16.95/gallon ($4.49/L)? That adds up when they fire the stuff out of a cannon, in this case to the tune of $712. That's about $20 for every second they sprayed us.

I know that sounds outrageous, but it was actually a lot cheaper to deice in Omaha than in our home base of Toronto Pearson, where the airport association has a monopoly on de-icing facilities and they jack the price outrageously because they can. Last time we got de-iced in Toronto, the bill was $2,500.00. Still, it's better than trying to fly an iced-up plane and littering the countryside with aircraft parts, so that's what we'll continue to do.

Friday, January 15, 2010

Please donate what you can to relief efforts in Haiti. I can't get over the images I'm seeing on TV and the web.

This link will take you to the Canadian Red Cross where you can donate online.

Tuesday, January 05, 2010

I respect icing, but it usually doesn't make me sweat in the jet.

This turned out to be a long story, so you are forewarned...

We flew up north to Timmins last night for a passenger pickup and return to Toronto. Kitsch was in New York with the Bravo so I was accompanied on this flight by Pepper, a fellow Captain I borrowed from a friendly competitor, and who has allowed me to call him Pepper for this story, so here we go...

Pepper and I had met years before while flying medevacs and had kept in touch, only to wind up years later flying the same type of aircraft out of the same airport. In fact, the last time I flew with him was a few months ago, in 'his' Citation and I was his f/o. Last night it was 'my' Citation and I was Mr 4-bars, not that it really matters for the purpose of this story.

Checking the weather before the flight, we knew a warm front was over our destination. It's all relative, and a warm front in this case means air that's maybe 5 or 6 Celsius overrunning air that's closer to -15c. Precipitation is usually the result, sometimes making beautiful snowflakes. Unfortunately it's not always a joyous occasion, as unfrozen precipitation from the overrunning warm air mass can fall through the cold air layer and (through *magic*) become supercooled without actually freezing until it hits a solid object. You know what's a solid object? An airplane!

If heavy freezing precipitation hits an aircraft, it can easily overpower the most robust anti-ice and de-ice systems ever built, very rapidly destroying the wings ability to produce lift and clogging all sorts of important air intakes, coating radio antennas and frosting over the windshield. For starters.

As a jet we generally don't spend much time in icing conditions - when we take off we can quickly climb up high enough that it's too cold for ice to form, but upon arrival we generally spend about 10 minutes at a low altitude when approaching and landing at an airport. This is all relevant because Timmins was reporting light freezing drizzle throughout the day. I called ahead and made sure the airport operator would have ground personnel available to de-ice us once we landed, and we got that all coordinated. The runway was constantly being sanded and plowed, and the runway friction index was decent, so that part looked fine too.

Anyway, I guess my point is we were primed to expect messy weather and icing, but it was still predicted to be within the capabilities of the aircraft. The conditions didn't look too bad on paper, and the weather was decent at various alternate airports along the route, so we lit up and headed to Timmins.

The departure was uneventful, and we cruised well above any clouds for an hour while talking about airplanes and playing with the on-board satellite weather. We noted the weather in Timmins had improved from absolute minimums to 3 miles visibility in freezing drizzle, with a ceiling of a thousand feet.

ATC told us the tops of the clouds were around 13,000' and we could expect possible ice in the clouds during the descent. I turned on our anti-ice system to let the various parts warm up before we descended through the clouds. Our hot bits got hot and we punched through the tops of the clouds a few minutes later.

It really didn't take long after that.

Me: "Hmm, we sure are picking up a lot of ice"
Pepper: "Yep. Maybe an inch. I can see it on the wingtip light gates. You wanna blow those boots again?"
Me: "Yep"

We were then descending through about 9000' on the approach to Timmins and the icing started to increase in intensity. All our anti-ice equipment was on, and I was regularly cycling the rubber boots on the wings to knock off ice that was just as rapidly accumulating. No huge deal, and not unsafe - everything is functioning as it should. I told myself this as I watched huge plates of ice fall off the wings every time the boots inflated.

A couple of minutes later, ATC lined us up for the runway and we started our final descent along the ILS glideslope into Timmins. We broke through the bottoms of the clouds about 10 miles from the runway.

Normally that's a good thing, but Pepper and I greeted it with consternation. We could see out the side windows just fine, but the ground visibility revealed that our front windshield was completely covered in ice, as in armour-plated. It was dark and we simply hadn't noticed because we wouldn't have seen anything anyway until the last few minutes of the flight. Our windshield is heated by taking hot air from an engine and blowing it over the outside of the windshield, and it's normally a pretty effective system, but the freezing precipitation we were flying through was really sticky, and it simply overpowered our bleed air heat.

I flipped another switch which started to drench the windshield with isopropyl alcohol, much like windshield washer antifreeze. We have about 20 minutes of fluid, which should be more than enough to eventually get the ice off the windshield, but it's not an instant process. In the past 5 years of flying the jet in Canadian winters, I have never gotten to flip this switch before, so I guess that was cool.

Me: "Okay, let's do a missed approach and maybe hold for a few minutes to see if the alcohol does the trick and we can see."
Pepper: "Okay, I'll let ATC know that we want to go around and hold in the icing while waiting for the icing to disappear"
Me: "If worst comes to worst we can always climb up to altitude and let the ice sublimate."
Pepper: "How much does your plane cost to operate per hour?"
Me: "You were adopted and your cat hates you"

Now before you get all freaked out, I want to make the clear point that we are in *NO* danger at any time during this event - if worst came to worst we'd just fly back to Toronto, where the skies were clear, and during the flight the windshield ice would likely sublimate entirely, but the whole point of this trip was to go to pick someone up and bring them to Toronto, so we didn't want to give up just yet.

We turned off all the airvents in the cockpit, further strengthening airflow to the windshield. I slowed the plane down by 80 knots in the hopes that decreased airflow over the windshield will slow ice accumulation and heat dissipation, and maybe let the windshield alcohol soak in a little better.

We executed a missed approach and told ATC why, and they immediately got very curious and wanted all sorts of details which Pepper happily provided. We didn't climb up very high and were able to stay below the cloud layer, which helped slow the accumulation of ice, but the ice never stopped building. Of course all this time I was cycling the de-ice boots constantly, and the wings were doing okay.

We started to orbit the general area of the airport and waited to see what happened next. What happened next was that I started to be able to make out a faint strip near the bottom of the windshield where the alcohol was soaking in and melting some of the ice. Pepper said the visibility out his side was improving also, so that was cool. We decided to shoot another approach and see if we could see the runway by the time we needed to land, so we flew around and got all lined up with the runway again, about 10 miles back from the threshold.

Pepper: "Runway in sight"
Me: "You lie"
Pepper: "No, really. I can see it out my side"
Me: "I got nuthin'. Could you see enough to land if you had to?"
Pepper: "Cool! Yeah I could!"
Me: "Okay, you have control"

Pepper flew the ILS all the way down to a remarkably smooth landing, especially since we land the airplane from the right seat about once a year, usually during sim training. I was only able to see indistinct blobs out the front of my windshield the entire time, but once we got on the ground I was able to taxi by looking out the side windows.

After we landed, 4 ramp guys came out and started to look at the airplane and point. On the unprotected areas of the airplane there was enough ice to supply the cocktail needs of Keith Richards himself.

Our passengers were already there, so we loaded them up and waited while the de-ice truck blasted hundreds of litres and thousands of dollars worth of pink heated de-ice fluid on our airplane, scrubbing her clean and helping protect her while we taxied to the runway for departure.

We departed less than three minutes after getting hosed down, climbing through the icing layers and into clear air less than four minutes after that. The same warm front that was affecting Timmins was also starting to wreak havoc in the Toronto area, and we could see approaching precipitation. We managed to beat the precipitation in and I was able to actually land the airplane on this leg, so that was fun.

I wasn't even going to write about this, but two things made me:

1. An hour after we landed in Toronto, a departing Boeing 777 reported severe icing on the climbout. The Boeing 777 is a totally badass, huge jetliner and for them to report severe icing gives you some indication of the potency of the weather system.

2. This CADORS report, on an aircraft that arrived in Timmins 1 hour after we did:

Date: 2010-01-04

The Beech A-100 aircraft was on a flight from [origin not reported] to Timmins Airport (CYTS). The flight crew reported difficulty seeing out of the cockpit windshield due it being frozen. The flight crew declared an emergency and ARFF services were called out from the city. The aircraft landed at 0313Z without incident and the ARFF service equipment was released.

That gave me the chills when I read it today - I was browsing the CADORS to see if our airplane was mentioned - if an airplane in Canada overshoots for any reason a CADORs report is normally generated, but it appears we might have gotten lucky, both in the CADORS and in real life.

Monday, January 04, 2010

We did a trip to Quebec a few weeks ago, and I found the instrument approach here interesting from a pilot-geek perspective. Instrument approaches are what we use to line up with the runway even if we can't see outside due to clouds etc.

When I fly the jet, I mostly go to large airports that use ILS navigation technology which lets us get right down to the runway before having to look outside. However, not all airports have the capability to install ILS's, and a good rule of thumb is the more remote the airport, the more primitive the instrument approach.

The NDB approach certainly wins the 'most primitive' prize - it's old, not very accurate and has been almost completely replaced by more accurate forms of navigation. Basically you are following an arrow on an instrument which points to various radio stations on the ground, but the arrow tends to waver and wander and lag and point at thunderstorms instead of navigation aids etc, so it's not the most desirable way to find the airport, but it's legal (and presumably safe).

For those of you who don't do this sort of thing, this particular instrument approach goes roughly like this:

1. Dial the Thetford Mines beacon frequency (275) in on your navigation receiver.
2. Fly to the Thetford Mines beacon If you are coming from the west, you can descent to 3,500 feet once you are within 25 miles of the airport. If you are coming from the east, you can only descend to 6,000 feet - this tells us there is high terrain or maybe a radio tower in that area.
3. Once you cross the beacon, turn to a track of 235, which is heading southwest, and descend to 2,900'
4. Fly outbound on the 235 track for a while, maybe a minute. You have 10 miles of protected airspace, so make sure your timing leaves you within your 10 protected miles.
4. After your minute is up, turn left to a track of 190, fly for 30 seconds, then make a 180-degree turn to the right to a track of 010.
5. Hold the track of 010 to intercept the desired inbound track of 055.
6. Once you are established on your inbound track of 055, you can descend to your minimums of 2500'. The chart lists 3 miles as a visibility you'll likely need in order to see the runway, but in Canada visibility is an advisory value only.
7. Look outside for the airport. If you see it before you cross the Thetford Mines beacon then circle to the south, not descending below 2,500' until you are in a position to land. If you cross the beacon and don't see the airport, climb to 3,500' and make a left turn back to the beacon and hold.

First, let's follow along with me as I take a boo at the approach:

The minimums on this approach still keep us over 1,000' in the air, so I start to dimly realize there are other factors in play, like maybe the airport being in between a bunch of hills. Oh, also:

1. It's an NDB approach, which is a fairly old and inaccurate way of finding the runway.
2. It's to a relatively small 4,500' strip. The shortest field we will operate out of is 4,000', and that's only if the runway is clean and the airplane is light.
3. The NDB navigation aid is right at the airport, which can make the approach a little tight.
4. There is no circling north of the field, except;
5. If you miss the approach, you are expected to turn to the north.
6. The procedure turn is to the south, and if you see the field, you are expected to circle south, where a hilltop 89' below the airplane lurks.
7. There is no local altimeter setting, you are supposed to use a remote one.
8. There is a restricted area (open-pit blasting for an asbestos mine) just to the east, so straight-out departures are out of the question.

This is a clip of us circling to the south of the field. You can see the 2,411' tall hill looming in the fog at around 0:15 into the video. The rest of the video is kinda boring and my battery cut out just before we touched down, so skip it if you'd like.

Once we landed, we shut down and chased our passengers away for a few hours. The airport was closed the day we arrived, and we picked up a pile of ice on the way in. We tried using the credit-card scraper method, but the ice was really sticky and I broke my library card, so we went with plan B:

The middle part where we start the engine is a lot more boring than I had hoped, but check out near the end of the clip where the Captain deploys the thrust reverser. Thrust reversers are cool :)

The howling sound at the end is me singing along with the engine.