For those who haven't seen this on AVWEB... some comedians have fun with a simulator.
Monday, April 30, 2007
Sunday, April 29, 2007
The Good, the Bad, and The (Plane) Weird
Last Sunday was another beautiful day to be flying. Well it got a little windy towards evening, but even so it was good. This weekend the weather is bad so I'm going to write about flying instead.
Last weekend a friend and I were off on a flight for visiting and lunch. During outbound cruise listening to other pilots try to contact air radio, wondering if they were aware of the frequency changes that have been happening at RCOs for quite a while, or if the specialists were really that busy, my mind turned to how much has changed since I first soloed, and how much hasn't. At home that evening unable to shake the reminiscent mood, I thought about all the varied experiences I've had. It is difficult to categorize flights by superlatives but three flight still stand out over all others.
One of the best, too many years ago, was my chance to fly with a WWII Spitfire pilot. It was my first season as a familiarization pilot with the Air Cadet gliding program. For several decades now the Air Cadet League and the Canadian Forces have been maintaining and operating a fleet of gliders (mainly Schweitzer SGS 2-33As) to provide air experience and flight training. A new squadron had been created, the new cadets were our passengers for the day. I have always enjoyed introducing young people to the joy of flight. It didn't (and doesn't) matter to me if the passenger wanted to drift around quietly, try their hand flying the glider, or enjoy the ride while I wrung the machine out to our maneuvering limits.
Near the end of the day I was surprised to see a elderly gentleman helped aboard and strapped into the glider. While chatting during the wait for hookup and launch I learned he was the Commanding Officer of the new squadron. I then started my normal spiel of explanations and questions, what not to touch, what I might ask him to adjust, if he had ever flown in a light plane before. At this point the conversation took a bit of a turn when he said, "Yes, but not in a long time. I flew Spits in the war but haven't flown since." You can imagine for a young Air Cadet it was like finding God in the passenger seat. The rest of the flight we talked about the differences and similarities Spitfire vs 2-33, traded control back and forth for demonstrations, generally enjoying the freedom of the sky. All too soon, our altitude bleeding away, it was time to land. Over the years the memory of many flights have run together like water colours in the rain, but this one remains as clear as if it happened only yesterday.
One of the worst was on a flight into Kaslo British Columbia. At the time the runway was not paved, but the mountains and hills were there. A friend and I used to rent a Grumman Tiger, one of us would fly out, the other back. Some times we would go for lunch, other times practice air work, this time we were exploring. It was my leg, after some discussion we decided to have a look at the Kaslo airport.
At the time the CFS entry cautioned that the runway formed part of a logging road, advising pilots ensure it was not obstructed by vehicles. Today the road is beside the runway, but the same advisory exists. Good advice! We circled over the airport inspecting the runway for condition and obstructions. I also paid particular attention to the terrain surrounding the airport. I elected to approach from over the lake, this would have us landing towards the mountain, but seemed safer than turning at low level in the potentially squirrelly winds in the valley. It was obvious that a go-around from less than a few hundred feet above the runway would problematical at best, very dangerous at worst. With this in mind I decided that if the approach did not look perfect at 300 feet I would execute a climbing turn to the left back out over the lake and think about things.
With a plan in hand I settled into the down wind leg. One of the problems with landing at a runway where the final approach is over terrain lower than the runway, and/or terrain rises past the runway, is that the visual cues pilots can come to depend on are missing or distorted. It is easy to to get off the glide slope. On final, nearing my personal decision height of 300 feet with full flaps and idle power I was not completely happy with my position. So in keeping with the plan I announced the go around. This is when everything went pear shaped.
I was following my training: full power, pitch to arrest descent without loosing airspeed, accelerate to best angle of climb, climb while retracting flaps slowly. In a total failure of cockpit resource management (did we even have CRM back then?), my friend assumed I would use the technique he was taught: full power, retract flaps, accelerate to best angle of climb, pitch to climb away. Without telling me he selected flaps up, the electric flap drive happily wound them in to the full up position. Either technique would have worked, in fact this horrible mixture worked as well otherwise I might not be able to write about it these many years later. With full power, my experience in the plane told me we should stop descending, but the runway (and more importantly the trees) continued to get nearer! The retracting flaps were dumping lift faster than our increasing airspeed could replace it. I was sure we would not be able to climb over the trees at the end of the strip, let alone the hills ahead and on both sides.
I was just about to secure the engine, fuel and electrical systems in preparation for running off the end of the strip into the trees when my friend asked "Why are you pitching up when the flaps are retracting?"
To which I said "Why are the flaps retracting?"
"I started retracting them for the go around! Isn't that what you want?"
"No!"
It was the wrong time to start communicating about go around procedure, but knowing what the issue was I waited out the flap retraction, the airplane began to climb away at its normally astounding rate, easily clearing all obstacles. Maybe because I was 17, I tried again. I was rewarded with an uneventful landing.
The weirdest flight I've ever had was also in the Air Cadet gliding program in Grand Forks BC. (There is also a weather cams there, looking east and west.) It was the start of my second season so I needed a currency check after a winter hiatus. The check syllabus involved a simulated rope break and a tow to 3000 feet above the airport for spin, spiral and stall recovery demonstrations. It was early on a cool crisp spring morning without a cloud in the sky. The instructor and I briefed, boarded and launched, completed the rope break and recovery then launched again for the upper air work.
During the long tow the instructor was asking me about the landmarks around the airport. I thought it was part of the check ride, but it turned out he had never flown out of that airport before. The flight sequences went well, at least the instructor seemed happy (as much as I could tell with him in the back seat). We had managed to get everything done before we had lost much altitude so he started using the remaining flight for some advanced lessons. During the tow up some light wispy clouds had formed on the mountain slopes. This was quite common and didn't cause us concern but it was something we were watching. While we were watching a layer of cloud, thin at first but thickening quickly formed a few hundred feet below us. It was clear what had happened. At dawn the heat of the sun had evaporated the dew creating a layer of warm humid air near the ground. The warm air rose, and as it rose cooled. Aviatrix has a series of posts that explain this process. When it had risen far enough to cool to the correct temperature, the humidity condensed quickly forming a solid layer of cloud under us over the whole valley. Not good.
You can usually count on an instructor keeping cool. From the back seat, in calm tones came the words "So, penetrating an under cast. What do you think we should do?" The glider (like most) had very simple instruments: air speed indicator, altimeter, variometer, compass, and a yaw string. I could maintain correct pitch by reference to the air speed, keeping the yaw string centred would keep us in coordinated flight. I could set up a straight and level glide before we entered the cloud, the compass would tell me if a turn developed, but if any significant rate of turn developed it would become useless due to northerly turning error. We could estimate the location of the airport from the mountains sticking up through the clouds, enter the under cast there, do our best to maintain straight and level flight hoping there was enough room under the cloud to find a safe landing area. I explained all this to him, his reply was simple: "You will have to do it, I don't know where the airport is and I can't see the compass."
We had a plan, soon we were positioned and descending into the cloud deck. We were both quiet, the air was smooth so flying the plane was largely resiting the temptation to do something with the controls. Suddenly I heard the thunk of the door latch and a louder hiss from disturbed slip stream. He had opened the door. The glider started to slowly yaw then roll right. I gently corrected until I heard the door slam then centered the controls. Thank God for positive stability. Shortly I again heard the open and corrected again. I asked "What are you doing?"
"I'm looking down to see if the ground is visible straight down." he replied. Now I knew how Henry Ford's pilot felt in The Battle of the Bulge.
"Ok, but every time you do that the glider yaws and banks right."
"Sh*t! Sorry" the door slammed for the last time. A moment later the the ground came into view. No tanks or fuel depot but the runway was well within gliding distance. We landed and got out to wait for the sky to clear. "Good ride." he said and walked away.
Safe flight.
Last weekend a friend and I were off on a flight for visiting and lunch. During outbound cruise listening to other pilots try to contact air radio, wondering if they were aware of the frequency changes that have been happening at RCOs for quite a while, or if the specialists were really that busy, my mind turned to how much has changed since I first soloed, and how much hasn't. At home that evening unable to shake the reminiscent mood, I thought about all the varied experiences I've had. It is difficult to categorize flights by superlatives but three flight still stand out over all others.
One of the best, too many years ago, was my chance to fly with a WWII Spitfire pilot. It was my first season as a familiarization pilot with the Air Cadet gliding program. For several decades now the Air Cadet League and the Canadian Forces have been maintaining and operating a fleet of gliders (mainly Schweitzer SGS 2-33As) to provide air experience and flight training. A new squadron had been created, the new cadets were our passengers for the day. I have always enjoyed introducing young people to the joy of flight. It didn't (and doesn't) matter to me if the passenger wanted to drift around quietly, try their hand flying the glider, or enjoy the ride while I wrung the machine out to our maneuvering limits.
Near the end of the day I was surprised to see a elderly gentleman helped aboard and strapped into the glider. While chatting during the wait for hookup and launch I learned he was the Commanding Officer of the new squadron. I then started my normal spiel of explanations and questions, what not to touch, what I might ask him to adjust, if he had ever flown in a light plane before. At this point the conversation took a bit of a turn when he said, "Yes, but not in a long time. I flew Spits in the war but haven't flown since." You can imagine for a young Air Cadet it was like finding God in the passenger seat. The rest of the flight we talked about the differences and similarities Spitfire vs 2-33, traded control back and forth for demonstrations, generally enjoying the freedom of the sky. All too soon, our altitude bleeding away, it was time to land. Over the years the memory of many flights have run together like water colours in the rain, but this one remains as clear as if it happened only yesterday.
One of the worst was on a flight into Kaslo British Columbia. At the time the runway was not paved, but the mountains and hills were there. A friend and I used to rent a Grumman Tiger, one of us would fly out, the other back. Some times we would go for lunch, other times practice air work, this time we were exploring. It was my leg, after some discussion we decided to have a look at the Kaslo airport.
At the time the CFS entry cautioned that the runway formed part of a logging road, advising pilots ensure it was not obstructed by vehicles. Today the road is beside the runway, but the same advisory exists. Good advice! We circled over the airport inspecting the runway for condition and obstructions. I also paid particular attention to the terrain surrounding the airport. I elected to approach from over the lake, this would have us landing towards the mountain, but seemed safer than turning at low level in the potentially squirrelly winds in the valley. It was obvious that a go-around from less than a few hundred feet above the runway would problematical at best, very dangerous at worst. With this in mind I decided that if the approach did not look perfect at 300 feet I would execute a climbing turn to the left back out over the lake and think about things.With a plan in hand I settled into the down wind leg. One of the problems with landing at a runway where the final approach is over terrain lower than the runway, and/or terrain rises past the runway, is that the visual cues pilots can come to depend on are missing or distorted. It is easy to to get off the glide slope. On final, nearing my personal decision height of 300 feet with full flaps and idle power I was not completely happy with my position. So in keeping with the plan I announced the go around. This is when everything went pear shaped.
I was following my training: full power, pitch to arrest descent without loosing airspeed, accelerate to best angle of climb, climb while retracting flaps slowly. In a total failure of cockpit resource management (did we even have CRM back then?), my friend assumed I would use the technique he was taught: full power, retract flaps, accelerate to best angle of climb, pitch to climb away. Without telling me he selected flaps up, the electric flap drive happily wound them in to the full up position. Either technique would have worked, in fact this horrible mixture worked as well otherwise I might not be able to write about it these many years later. With full power, my experience in the plane told me we should stop descending, but the runway (and more importantly the trees) continued to get nearer! The retracting flaps were dumping lift faster than our increasing airspeed could replace it. I was sure we would not be able to climb over the trees at the end of the strip, let alone the hills ahead and on both sides.
I was just about to secure the engine, fuel and electrical systems in preparation for running off the end of the strip into the trees when my friend asked "Why are you pitching up when the flaps are retracting?"
To which I said "Why are the flaps retracting?"
"I started retracting them for the go around! Isn't that what you want?"
"No!"
It was the wrong time to start communicating about go around procedure, but knowing what the issue was I waited out the flap retraction, the airplane began to climb away at its normally astounding rate, easily clearing all obstacles. Maybe because I was 17, I tried again. I was rewarded with an uneventful landing.
The weirdest flight I've ever had was also in the Air Cadet gliding program in Grand Forks BC. (There is also a weather cams there, looking east and west.) It was the start of my second season so I needed a currency check after a winter hiatus. The check syllabus involved a simulated rope break and a tow to 3000 feet above the airport for spin, spiral and stall recovery demonstrations. It was early on a cool crisp spring morning without a cloud in the sky. The instructor and I briefed, boarded and launched, completed the rope break and recovery then launched again for the upper air work.
During the long tow the instructor was asking me about the landmarks around the airport. I thought it was part of the check ride, but it turned out he had never flown out of that airport before. The flight sequences went well, at least the instructor seemed happy (as much as I could tell with him in the back seat). We had managed to get everything done before we had lost much altitude so he started using the remaining flight for some advanced lessons. During the tow up some light wispy clouds had formed on the mountain slopes. This was quite common and didn't cause us concern but it was something we were watching. While we were watching a layer of cloud, thin at first but thickening quickly formed a few hundred feet below us. It was clear what had happened. At dawn the heat of the sun had evaporated the dew creating a layer of warm humid air near the ground. The warm air rose, and as it rose cooled. Aviatrix has a series of posts that explain this process. When it had risen far enough to cool to the correct temperature, the humidity condensed quickly forming a solid layer of cloud under us over the whole valley. Not good.
You can usually count on an instructor keeping cool. From the back seat, in calm tones came the words "So, penetrating an under cast. What do you think we should do?" The glider (like most) had very simple instruments: air speed indicator, altimeter, variometer, compass, and a yaw string. I could maintain correct pitch by reference to the air speed, keeping the yaw string centred would keep us in coordinated flight. I could set up a straight and level glide before we entered the cloud, the compass would tell me if a turn developed, but if any significant rate of turn developed it would become useless due to northerly turning error. We could estimate the location of the airport from the mountains sticking up through the clouds, enter the under cast there, do our best to maintain straight and level flight hoping there was enough room under the cloud to find a safe landing area. I explained all this to him, his reply was simple: "You will have to do it, I don't know where the airport is and I can't see the compass."
We had a plan, soon we were positioned and descending into the cloud deck. We were both quiet, the air was smooth so flying the plane was largely resiting the temptation to do something with the controls. Suddenly I heard the thunk of the door latch and a louder hiss from disturbed slip stream. He had opened the door. The glider started to slowly yaw then roll right. I gently corrected until I heard the door slam then centered the controls. Thank God for positive stability. Shortly I again heard the open and corrected again. I asked "What are you doing?"
"I'm looking down to see if the ground is visible straight down." he replied. Now I knew how Henry Ford's pilot felt in The Battle of the Bulge.
"Ok, but every time you do that the glider yaws and banks right."
"Sh*t! Sorry" the door slammed for the last time. A moment later the the ground came into view. No tanks or fuel depot but the runway was well within gliding distance. We landed and got out to wait for the sky to clear. "Good ride." he said and walked away.
Safe flight.
Saturday, April 21, 2007
COPA Flight Log - Electronic Logbook. Part 4
In this series of articles I'm detailing my experience with COPA Flight Log. The last two times I've been flying I have made two flights. So I use the "Save & New" new button after the first entry, the "Save & Close" button after the second. Both times this resulted in the program crashing and loosing the entries. Making them one at a time and using the "Save & Close" button after each entry seems to work, but it is frustrating. I don't think I could trust it if I had more than two entries to make in a session.
I'm still using it, and still finding issues, but it does provide some value that I like. I'm still keeping a hard copy log book, but I've stopped updating my spreadsheet and database.
I'm still using it, and still finding issues, but it does provide some value that I like. I'm still keeping a hard copy log book, but I've stopped updating my spreadsheet and database.
The Good, the Bad, and the Ugly - Picture
Last night I told you about an incident involving a Cessna 172. Today I have a picture of one propeller tip so you can see what happens when a spinning prop strikes pavement. This is one of the "best" curls I've seen in a prop, though I'll have to admit to not seeing all that many.
When running, in this position the blade would have been moving downward. The forward movement of the airplane tends to cause the tips to bend aft. Successive strikes change the initial bend into a curl, the rotation of the prop gives it a characteristic spiral. It is a very interesting, if expensive and disturbing, shape.
Friday, April 20, 2007
The Good, the Bad, and the Ugly
The weather is good. It looks like the daytime surface temperature will be above the magic 50 degrees Fahrenheit at which point we are obliged to remove the oil cooler cover plate. Most airplane engines have an oil cooler. Some are mounted directly to the engine, some like mine are mounted some distance away. In either case it is like a tiny radiator, engine oil circulates through and is cooled by air flowing through the engine compartment. In cold weather the cooler is too efficient so it is desirable to reduce the amount of airflow. On my Cherokee this is accomplished by removing the air duct that delivers cooling air, inserting a specially constructed aluminum plate and reconnecting the duct. There is no low temperature at which I must install the plate, but it must be removed above 50F.
This is also a good time to re-install the wheel pants. Wheel pants are fiberglass covers that reduce the drag caused by air flowing around the wheels. In the winter time, snow slush and ice can get jammed in the pants. This is as bad for the plane as it sounds because during a flight this can freeze the wheels solid making landings difficult or unsafe.
While getting this intimate with the airplane it is also a good time to look at every thing in and around the engine and landing gear to see how things are wearing, aging etc. Everything looked good. The test flight went well, everything stayed attached so I went for a long enjoyable tour around the local area.
So what could be bad, or ugly? It seems last night a Cessna 172 had a hard landing, collapsing the nose wheel. No one was injured. I don't know any of the details, and it would be unfair to speculate, but some things are know to all pilots. Tricycle gear equipped airplanes have relatively delicate nose wheels. They are designed essentially to keep the propeller out of the mud and steer on the ground. They are not designed to take the forces of landing so pilots are trained to land on the main gear first. When the nose gear breaks on landing, the propeller no longer has adequate clearance. With the engine turning the prop strikes the runway repeatedly getting curled back along its length. The engine is shock loaded to the point where an inspection or over hall is required. An accident like this can easily result in the insurance company writing off the airplane.
No pilot likes to see the result of an accident sitting alone and forlorn where is was dragged off the runway. To me the bent, twisted and crumpled aluminum that used to be an airplane is ugly.
This is also a good time to re-install the wheel pants. Wheel pants are fiberglass covers that reduce the drag caused by air flowing around the wheels. In the winter time, snow slush and ice can get jammed in the pants. This is as bad for the plane as it sounds because during a flight this can freeze the wheels solid making landings difficult or unsafe.
While getting this intimate with the airplane it is also a good time to look at every thing in and around the engine and landing gear to see how things are wearing, aging etc. Everything looked good. The test flight went well, everything stayed attached so I went for a long enjoyable tour around the local area.
So what could be bad, or ugly? It seems last night a Cessna 172 had a hard landing, collapsing the nose wheel. No one was injured. I don't know any of the details, and it would be unfair to speculate, but some things are know to all pilots. Tricycle gear equipped airplanes have relatively delicate nose wheels. They are designed essentially to keep the propeller out of the mud and steer on the ground. They are not designed to take the forces of landing so pilots are trained to land on the main gear first. When the nose gear breaks on landing, the propeller no longer has adequate clearance. With the engine turning the prop strikes the runway repeatedly getting curled back along its length. The engine is shock loaded to the point where an inspection or over hall is required. An accident like this can easily result in the insurance company writing off the airplane.
No pilot likes to see the result of an accident sitting alone and forlorn where is was dragged off the runway. To me the bent, twisted and crumpled aluminum that used to be an airplane is ugly.
Saturday, April 14, 2007
Safety Audit or Safety Management?
The Edmonton Journal is reporting that "Transport Canada fears ending regular airline safety audits could be risky" in an article based on a March 2006 departmental risk assessment obtained through an Access to Information Act request. The Transport Minister Lawrence Cannon counters that the Safety Management System (SMS) actually increases oversight.
The only exposure I've had to the SMS was presented at Transport Canada safety seminar. Necessarily it could not be an in depth or exhaustive treatment of the subject, but none of it struck me as suitable to enforcing safety without cooperation from aviation companies. The safety audit system likely has problems as well, but I guess like the authors of the risk assessment I'm yet to be sold on SMS.
The only exposure I've had to the SMS was presented at Transport Canada safety seminar. Necessarily it could not be an in depth or exhaustive treatment of the subject, but none of it struck me as suitable to enforcing safety without cooperation from aviation companies. The safety audit system likely has problems as well, but I guess like the authors of the risk assessment I'm yet to be sold on SMS.
Thursday, April 12, 2007
CAE adds three flight training organizations to CAE Global Academy
Somewhat echoing comments made over on Cockpit Conversation CAE (a world leader in simulation and modeling) has announced the addition of three flight training organizations to their Global Academy. One facility is located in the U.S. (SAA Flight Training, based in San Diego), the other two are located in Moncton and Brussels.
The stats quoted in the CNW Group article are amazing, but of greater interest to me is that a heavy metal simulator giant is gathering a network of ab-initio, and advanced training organizations around the world. Could this radically change how most commercial pilots are trained in the future? If so, what impact will that have on personal and recreational flight training? Coupled with the changes that we have seen with the evolution of NAV Canada, those proposed for the FAA, the fluid situation in Australia, security concerns and VLJs; we could see more significant changes is aviation in the next 20 years than in the last 40.
The stats quoted in the CNW Group article are amazing, but of greater interest to me is that a heavy metal simulator giant is gathering a network of ab-initio, and advanced training organizations around the world. Could this radically change how most commercial pilots are trained in the future? If so, what impact will that have on personal and recreational flight training? Coupled with the changes that we have seen with the evolution of NAV Canada, those proposed for the FAA, the fluid situation in Australia, security concerns and VLJs; we could see more significant changes is aviation in the next 20 years than in the last 40.
Tuesday, April 10, 2007
NavCan to brief pilots on Toronto area airspace changes
In an article from COPA comes news of upcoming changes to airspace around Greater Toronto Area airports. From July 5, 2007 a Mode C Transponder will be required above 6500MSL from 26nm to 65nm from the centre of the current TCA bullseye. A similar ring has existed around Ottawa for a number of years without a huge negative effect on GA. You should read the full COPA article though for there seems to be more in store for the GTA.
Friday, April 6, 2007
LITE-ON IT EZ-Dub USB DVD-RW
I purchased a Lite-On IT EZ-Dub external USB DVD re-writer when I started working on the UX300CN because I needed a DVD burner that I could hook up to save bundled software on. I wasn't at all interested in the EZ-Dub features, and since Microsoft Vista recognized the burner right away I had not even opened the set of CD that came with the drive until today. I needed to copy some files off an XP-Pro system that was old enough that it didn't have a DVD burner installed. No problem, I've got this external unit hanging around. I hooked it up, installed the drivers, which was a very simple process, and completely out of character, read the quick start guide.
If you've looked at the EZ-Dub link above, you know that they claim it is as simple as pushing the File button on the drive dragging/dropping files to write data to either CD, DVD or dual layer DVD. So I tried it, and guess what, it really is that simple! So if you are a Luddite, or know one you can do worse than looking at this unit. It is fairly large. It would have been nice if they used a laptop form factor drive to make the package more compact. There is also a block power supply, but at least it isn't a wall wart so it isn't necessary to re-wire the whole desk to find an outlet.
I haven't tried the Dub button yet but I expect it works equally well.
If you've looked at the EZ-Dub link above, you know that they claim it is as simple as pushing the File button on the drive dragging/dropping files to write data to either CD, DVD or dual layer DVD. So I tried it, and guess what, it really is that simple! So if you are a Luddite, or know one you can do worse than looking at this unit. It is fairly large. It would have been nice if they used a laptop form factor drive to make the package more compact. There is also a block power supply, but at least it isn't a wall wart so it isn't necessary to re-wire the whole desk to find an outlet.
I haven't tried the Dub button yet but I expect it works equally well.
Wednesday, April 4, 2007
Flight Patterns
A very interesting way to render flight data.
More images are available at Aaron Koblin's web site. He also has one of the most interesting home pages I've seen in some time.
Data from the U.S. Federal aviation administration is used to create animations of flight traffic patterns and density.
More images are available at Aaron Koblin's web site. He also has one of the most interesting home pages I've seen in some time.
New landing fees at Trudeau, Mirabel airports
New landing fees at Trudeau, Mirabel airports
Looks like high landing fees are back at Montreal's major airports again. According to a COPA article effective June 1, 2007 Montréal-Pierre Elliott Trudeau International Airport: Fixed rate of $35 per landing or fixed yearly rate of $1,000 per aircraft. Montréal-Mirabel International Airport: Fixed rate of $15 per landing or fixed yearly rate of $400 per aircraft.
Looks like high landing fees are back at Montreal's major airports again. According to a COPA article effective June 1, 2007 Montréal-Pierre Elliott Trudeau International Airport: Fixed rate of $35 per landing or fixed yearly rate of $1,000 per aircraft. Montréal-Mirabel International Airport: Fixed rate of $15 per landing or fixed yearly rate of $400 per aircraft.
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