CFN

Question

Hello Captain.  I am not a pilot, but I find aviation fascinating. I have been reading your weekly column with interest. My question is;  how does a pilot know when to start the descent from cruising altitude to land at destination airport ?

Question asked by Carlos.

Answer

The most efficient way to descend an airplane is to stay at cruising altitude for as long as possible, then reduce engine thrust to idle and descend all the way down to a runway, without increasing engine thrust. At idle power, jet engines produce little thrust and consume ten times less fuel that at cruise power.

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So the airplane basically glides toward the airport. Airliners have a relatively small wing compared to gliders, but they are aerodynamically very clean, so they can fly fast and consequently glide quite well.  A typical glide ratio of an airliner is approximately 18:1. That means that for every 18 feet of forward movement the airplane will descent one foot. This ratio translates to 3 nautical miles for every 1,000 feet of altitude loss.  If an airliner is cruising at 35,000 feet, to be able to land at an airport at an elevation close to sea level, the pilot must start the descent 105 Nautical Miles, or 190 kilometers from the airport.

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A pilot can easily make this mental calculation. There are however several factors that complicate this formula and the pilot has to make appropriate adjustments. Modern airliners have computers that can make this calculation very precisely, based on data entered by the pilot into the computers and on actual wind and environmental conditions.  The computers help the pilot to fly the airplane more efficiently, burning less fuel and thus also reducing emissions.

A bit more about Captain Dan:

Captain Dan Baz enrolled in Flight School at the age of 16.
He has completed studies in Aircraft Engineering and Master of Business Administration. He has been at the controls of many different types of aircraft, from single engine Cessnas to large intercontinental jets on global routes.

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Over the last four decades he has flown thousands of hours up in the blue sky.

Have a question for the Captain ? Send it to Captain Dan Baz captaindanbaz@yahoo.com Every week a question from the readers will be selected and answer posted in this column.

CFN

Question

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Can flight control of a commercial aircraft be taken over from the ground?

Question asked by Brad.

Answer

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Science fiction, movies and modern technology of computers, smart phones and other communication devices, would make one think that this certainly would be possible. And yes,  technology does exist to do that.  However, no commercial aircraft have  technology installed with capability to be controlled remotely. Remote control from the ground is used for satellites and spacecraft, as well as for military Unmanned Aerial Vehicles (UAV).  UAV’s are primarily used by United States Air Force (USAF) and Central Intelligence Agency (CIA). Unfortunately the safety record of UAV’s is not the best and would not be acceptable in Civil Aviation.

There is a story going around, that flight crews on flight decks of future airplanes will consist of one pilot only and a dog. The pilot’s job will be to feed the dog and the dog’s job will be to bite the pilot if he / she touches anything.  The fact is that airplanes still need direct human input, particularly if something does not go as planned, or if there is an emergency. Even with the largest and most modern airplanes today, at times pilots still must fly the airplane by the seat of their pants. That would not be possible to do by remote control.

There is also the human perception factor. Some say that with today’s technology we no longer need the pilots in the flight deck of airplanes. After-all many accidents are blamed on pilot error. However, would you get on an airplane knowing that there is no pilot on board and nobody to save the day if there is an emergency ?

If an airplane was being controlled from the ground, what would happen if the control signals were jammed, or intercepted by an unauthorized party ?  The result could be catastrophic.  At this point in time, fairly sophisticated technology exists for radio controlled model aircraft. However, what future technologies may bring to commercial aviation in the next fifty years, is anybody’s guess. We already have automated trains with no engineers on board. And passengers ride in them.

A bit more about Captain Dan:

Captain Dan Baz enrolled in Flight School at the age of 16.
He has completed studies in Aircraft Engineering and Master of Business Administration. He has been at the controls of many different types of aircraft, from single engine Cessnas to large intercontinental jets on global routes.

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Over the last four decades he has flown thousands of hours up in the blue sky.

Have a question for the Captain ? Send it to Captain Dan Baz captaindanbaz@yahoo.com Every week a question from the readers will be selected and answer posted in this column.

CFN

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Last week we had our Italian exchange class come and stay with us, and all of them stole a piece of me and brought it back to Italy with them. As I watched each and every one of them board their train to the airport, I hugged each one, and held in my tears as I realized that not only will this someday be me leaving Danmark for my journey to Canada, but that each and every one of these Italians have touched my heart in one way or another, and I’m really going to miss them.

But if there is one thing that I HAVE learned is that not all goodbyes are permanent.   Although it may feel like I am never going to meet up with these people ever again, I know now that that is a lie; because there are certain relationships that exchange students develope that guarantees them to last for a lifetime.   I’m not excited for the day where I will have to say goodbye to Denmark, but I know without a doubt that the goals that I came to Denmark with have been fulfilled.

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I have affected some people’s lives, changed them for the better and without meeting me, that is something that could have taken years to happen. And I know without a doubt that these relationships that I have developed will certainly last a lifetime.  As I sat at home on Sunday night, one of the italians sent me a message thanking me for being who I am, because she is very shy and doesn’t often come out of her shell, but because she met me, she said that she was inspired by me, and that she will try to live her life differently, all due to meeting me.

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This message is one of the main reasons that I chose to go on exchange, to effect someone’s life somehow, and now that I have, I must say that it was completely worthwhile, and it has made my exchange ten thousand times better because of her words.

Tabatha Pilon is a 17 year old student from Cornwall Ontario spending a year in Denmark.   She will be writing to us  each week or as her “gymnasium” schedule allows.

CFN

Question

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When my grandfather reached a certain age, he had to go for a driver test to keep his driver’s license. Are there any checks or tests for airline pilots, after a certain time, to demonstrate that they can still hold their license and safely fly an airplane ?

Question asked by Pauline.

Answer

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Airline and commercial pilots constantly undergo competency and medical checks, to maintain their pilot license.This is from the time the license is issued.  A pilot license, or an Aviation Document, is a booklet type document, similar to a passport. It has three sections in it. The first section describes the privileges of the license for which the pilot has qualified, the second section is to record pilot competency checks, the third section is to record medical certifications, which validate the license.

Once a pilot has qualified to fly under certain meteorological conditions, or how to fly a certain type of airplane, to maintain those privileges, pilots must regularly demonstrate their ability and competency to do so. Every six months, airline pilots and pilots employed in many other commercial operations must demonstrate in a sophisticated flight simulator, which is an exact replica of the type of airplane they fly, that they can safely operate the airplane under normal and emergency conditions. These flight simulator sessions are conducted by a Transport Canada approved check pilot and at times also monitored by a Transport Canada inspector. In addition, every twelve months, pilots must also demonstrate, to an approved check pilot, or a Transport Canada inspector, their performance on a regular revenue flight. This is called a Recurrent Line Check.

For the Pilot License to be valid, pilots must pass a medical certification examination, conducted by an Aeromedical doctor, approved by Transport Canada.  Airline and Commercial pilots must regularly undergo this examination. Pilots under 40 years of age every 12 months, pilots 40 years of age and over every 6 months.

Failure to pass any of the competency or medical checks could jeopardize a pilot’s job, or possibly his or her career.

A bit more about Captain Dan:

Captain Dan Baz enrolled in Flight School at the age of 16.
He has completed studies in Aircraft Engineering and Master of Business Administration. He has been at the controls of many different types of aircraft, from single engine Cessnas to large intercontinental jets on global routes.
Over the last four decades he has flown thousands of hours up in the blue sky.

Have a question for the Captain ? Send it to Captain Dan Baz captaindanbaz@yahoo.com Every week a question from the readers will be selected and answer posted in this column.

CFN

Question
I fly frequently on business and always carry my laptop, Blackberry phone and sometimes my tablet with me. The cabin crew always say to turn off and put away all electronic items for take-off and landing. What is the reason for it ?

Question asked by Jane.

Answer
We have become so dependent on computers and small electronic gadgets, that it is now difficult to live without them. A few months ago I misplaced my Blackberry, but fortunately I found it after three days. It was like loosing my right arm.

Electronic items like laptop computers, cellular phones, tablets, games and many others emit electromagnetic field, whenever they are turned on. This is even if the transmitting functions of these devices are turned off. Some items emit stronger electromagnetic field that others. Due to electromagnetic interference (EMI) with aircraft electronic systems, their performance and operation may be adversely affected.  Autopilots and Flight Guidance systems are of primary concern, particularly when an airplane is in critical phase of flight, like take-off and landing. There have been reports of malfunctions  of cabin pressure control systems, brake and anti-skid control and other aircraft systems, which have been suspected due to electromagnetic interference.

Several years ago one of these incidents occurred on one of my flights from Toronto to Europe. Half way across the Atlantic ocean the cabin pressure became erratic. I asked one of the flight attendants to check if anyone was using any electronic devices. She found, there was a gentleman near the front of the airplane using a calculator. I asked her to explain to him what was happening and if he would turn it off. Sure enough, after he turned off the calculator cabin pressure became stable again.

With so many electronic products on the markets today, it is impossible to test each one of them, during its normal operation, as well as if the item malfunctions, to determine what effect it would have on all airplane systems. Therefore, as we always do in aviation, it is always better to be conservative and to err on the safe side. This all comes down to a simple rule; all portable electronic devices must be turned off prior to take-off and landing.

Perhaps in the future this may change, as electronic products are designed better and produce less electromagnetic emissions. A lot of airplanes in the sky today have been designed 20 or more years ago and use technology of that time. Systems in new airplanes will be designed to be less susceptible to this kind of interference.

At altitude, in cruise flight, use of electronic items is allowed. In this phase of flight a possible malfunction of an aircraft system is not as critical. There are some systems now and others in development, that will turn an airplane cabin into a wireless hot spot and passengers will be able to use Internet during the flight.  Also there are a few airlines and others are in a trial stage, where pilots use tablets to access all navigation charts, airplane and company manuals. If tablets will replace all paper books and manuals carried in each flight deck, a weight saving of 100 kgs or more could be realized. This translates into fuel savings, as well as lower carbon emissions.

A bit more about Captain Dan:

Captain Dan Baz enrolled in Flight School at the age of 16.
He has completed studies in Aircraft Engineering and Master of Business Administration. He has been at the controls of many different types of aircraft, from single engine Cessnas to large intercontinental jets on global routes.
Over the last four decades he has flown thousands of hours up in the blue sky.

Have a question for the Captain ? Send it to Captain Dan Baz captaindanbaz@yahoo.com Every week a question from the readers will be selected and answer posted in this column.

CFN

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Answer

Airplanes at the beginning of aviation had no electrical systems at all. However, it was not long before airplanes needed lights to fly at night. In the 1920′s and 1930′s, as the electronic industry was developing, airplanes were equipped with Radio Transceivers and Receivers for voice communications, electronic systems for navigation and electric flight instruments.  Early small airplanes used small air driven generators. These were mounted externally on the airplane, driven by a small propeller. As airplanes grew in size and needed more electrical power, generators were mounted on the engines, in a similar fashion to automotive generators or alternators.

Today, in the 21st century and the age of electronics, we can hardly get by without electricity.  We need to plug in and charge our laptops, iPhones and Blackberrys and many other electronic devices that we can hardly live without. Meals on airplanes are heated in electric ovens. Airplane technology has changed dramatically in the last couple of decades. Electrical systems have become more reliable and dependable.  Airplanes have dozens of computers to run and monitor, flight control and other airplane systems. Flight instrument displays are basically sophisticated computer monitors, navigation and communication systems, they all require electrical power to operate.

Modern airliners today, must have electrical power to fly.  Therefore, airliners now have multiple, redundant electrical sources. There is at least one generator installed on each engine. Airplanes also have an Auxiliary Power Unit (APU) with electric generator, which can supply electrical power in flight as well as for ground use. Some airplanes have additional electric generators powered by airplane’s hydraulic systems. There are airplanes that also have wind driven emergency  generator.  This generator has much bigger capacity than those used in the early years of aviation.  As a last source of electrical power, airplanes have batteries and inverters, which can provide electric power to flight controls, flight displays and essential equipment, long enough for the crew to land the airplane.

Failure of any one generator does not compromise operation of modern airplanes. Electrical power produced by the generators is  three phase, 115 volts AC, at 400 Hz. High frequency allows for smaller and lighter electric motors in various airplane systems. On the ground, electric power for an airplane is supplied by a generator driven by airplane’s auxiliary power unit (APU), or from an external electric power source, through an umbilical cable connected to the airplane.

A bit more about Captain Dan:

Captain Dan Baz enrolled in Flight School at the age of 16.
He has completed studies in Aircraft Engineering and Master of Business Administration. He has been at the controls of many different types of aircraft, from single engine Cessnas to large intercontinental jets on global routes.
Over the last four decades he has flown thousands of hours up in the blue sky.

Have a question for the Captain ? Send it to Captain Dan Baz captaindanbaz@yahoo.com Every week a question from the readers will be selected and answer posted in this column.

CFN

Question
In an airplane cabin there are a lot of passengers in close proximity in a confined space.  Often many people are coughing, sneezing and perhaps have other ailments. What is the air quality like, in airplane cabins ?

Question asked by Jurgen.

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Answer

Air in an airplane cabin comes in from outside of the airplane. This ambient air at high altitudes, is clean and cold (as cold as -70 C or more).  The air is essentially dry, sterile and dust free, but low in partial pressure of oxygen, in fact, too low to sustain life. Therefore, the air must be compressed to a density that is healthy for passengers and crew.

The airflow is continuous and is used for maintaining a comfortable cabin temperature, pressurization and overall air quality. About half of the air exiting the cabin is exhausted from the airplane through one or more outflow valves, which also control the cabin pressure. The other half is drawn by fans through High Efficiency Particulate Air (HEPA) filters under the cabin floor, and then is mixed with the outside air coming in from the engine compressors.  The HEPA filters are very effective at trapping microscopic particles such as bacteria and viruses and can provide essentially particle free air in the recirculation system. Because of the way these filters are designed, their efficiency actually increases for particles both smaller and larger than the most penetrating particle size, which is about 0.1 to 0.2 microns.  The efficiency of HEPA filters to remove bacteria and viruses is greater than 99 percent.  Recirculating 50% of the air provides several benefits. It increases air humidity in the passenger cabin, which improves passenger comfort, especially on long haul flights.  It also reduces level of ozone in the cabin air and improves engine fuel consumption.

The air flow in the cabin is from the ceiling area, towards the sidewalls and out through the grills at the floor level. The air does not flow lengthwise through the cabin. Thus if air might be contaminated in one area of the cabin, it will not be spread to other areas.
The air in the cabin is completely replaced every two to three minutes. The air is of much better quality than air in an average home or an office building.

A bit more about Captain Dan:

Captain Dan Baz enrolled in Flight School at the age of 16.
He has completed studies in Aircraft Engineering and Master of Business Administration. He has been at the controls of many different types of aircraft, from single engine Cessnas to large intercontinental jets on global routes.
Over the last four decades he has flown thousands of hours up in the blue sky.

Have a question for the Captain ? Send it to Captain Dan Baz captaindanbaz@yahoo.com Every week a question from the readers will be selected and answer posted in this column.

CFN

Question
Airplanes normally fly through clouds, but why do they fly around thunderstorm clouds ?

Question asked by Colin

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Answer

Airliners are designed to fly trough clouds and can do so routinely without any problems. Thunderstorm clouds ( cumulonimbus ), are different from other types of clouds. There are several reasons why a pilot does not want fly an airplane into one.

Within thunderstorm clouds there are severe air updrafts and downdrafts. This results in severe turbulence. Obviously this would be very uncomfortable and disconcerting for
passengers and crew. There is a chance that some passengers and crew could be injured. Also, there is a possibility that the airplane might sustain damage.

The updrafts and downdrafts within thunderstorm clouds generate static electricity. The discharge of this electricity is what  causes lightning and thunder.  Lightning can also cause damage to airplanes, however this damage is generally minor. Airplanes do have protection and equipment to dissipate the effects of lightning strikes.

Thunderstorm, or cumulonimbus clouds, also contain a lot of moisture and ice. Updrafts within the cloud carry moisture from lower altitudes to high altitudes, where the moisture droplets will freeze instantly upon contact with airplane surface. The accumulation of ice on airplane’s wings can reduce lift the wings need to generate to maintain altitude. The moisture droplets can also turn into hail, which can do physical damage to an airplane.

Thunderstorm clouds in Canada can reach altitudes above 50,000 feet, or 10,000 meters. Pilots will fly around thunderstorm clouds by several kilometers. However, because of the size of these clouds it looks like an airplane might be just a few hundred meters away.

A bit more about Captain Dan:

Captain Dan Baz enrolled in Flight School at the age of 16.
He has completed studies in Aircraft Engineering and Master of Business Administration. He has been at the controls of many different types of aircraft, from single engine Cessnas to large intercontinental jets on global routes.
Over the last four decades he has flown thousands of hours up in the blue sky.

Have a question for the Captain ? Send it to Captain Dan Baz captaindanbaz@yahoo.com Every week a question from the readers will be selected and answer posted in this column.

CFN

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Question
I have heard about airplanes hitting birds.  How common and how bad a problem is it?

Asked by Iain

Answer
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Airplanes and birds seem to share the same sky and airspace around airports peacefully.  However, their coexistence is burdened with risk.  Sometimes they both end up occupying the same airspace at the same time. The results are not pretty, particularly for the birds. Bird-strike events are relatively common, occur most often on the ground or at low altitude, and are usually benign. However, bird strikes can have significant economic and occasional safety consequences for flight operations.

The first bird strike was recorded by the Wright brothers in 1905, and the aviation wildlife hazard has been a risk to aviation ever since. The January 15, 2009, ditching of US Airways Airbus A320 on the Hudson River in New Jersey, was the dramatic result of dual engine thrust loss arising from an airborne encounter with a flock of Canada geese.

Fortunately, due to the experience and skills of the flight crew there was no loss of life.

Single or multiple large birds, relatively small numbers of medium-size birds, and large flocks of relatively small birds are all problematic and have resulted in accidents. In Canada, a list of birds most hazardous to flight has been identified: large flocking waterfowl (Canada goose); gulls; pigeons and doves; blackbirds, starlings, and sparrows; and raptors (hawks and kestrels).

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Although bird strikes have been reported at altitudes above 10,000 feet, most bird strikes occur on or near the ground, on or close to airports. This highlights the need for wildlife management on airport grounds and in the vicinity. Features that are nearby or even at some distance from airfields can create different bird hazards to aircraft safety at each airport. For example, flight lines of birds between a nighttime roosting area and a daytime feeding area such as a landfill, can create serious hazards if the airport lies between these areas.

Pilots of fast airplanes, like airliners and other civilian and military jets, use several strategies to prevent bird strikes, such as; delaying take-off for landing in the presence of known bird activity near a runway, minimizing time that an airplane spends at low altitudes, flying at reduced speeds below 10,000 feet altitude and others.

A bit more about Captain Dan:

Captain Dan Baz enrolled in Flight School at the age of 16.
He has completed studies in Aircraft Engineering and Master of Business Administration. He has been at the controls of many different types of aircraft, from single engine Cessnas to large intercontinental jets on global routes.
Over the last four decades he has flown thousands of hours up in the blue sky.

Have a question for the Captain ? Send it to Captain Dan Baz captaindanbaz@yahoo.com Every week a question from the readers will be selected and answer posted in this column.

CFN

The Italian people are so warm and loving — so much like Canada — whereas Danes are more cold in that way. When I first came to Denmark, I was told that Danes were “open-minded, but not open-hearted” which makes me wonder why it is like this? There’s nothing wrong with it, that’s for sure, but it makes me wonder how exactly it has been voted to be the happiest country in the world, when they aren’t loud, boisterous or the hugging type like Italians or Canadians.

And it made me wonder…what is it that makes people happy?  It occurred to me, that despite the fact that people here are so different from Canadians and Italians, it is much safer and in itself, allows for people to be more happier. But I don’t think that comparing any nations will satisfy the question of what makes the people so happy. In all, it is a mystery.   As the return back to Denmark had made me not only physically ill, but also very homesick, I found myself sitting on a bench in the city center, and found myself watching everyone. I saw a lot of bland faces, but a lot of happy faces as well. And as I sat there, I realized how every one of these people were able to walk around feeling completely safe, and looking content.

They don’t have much to worry about, except maybe getting hit by a crazy cyclist, and they get the chance to do what they like, and despite the fact that they are not loud, or boisterous, nor do they run around smiling and talking to strangers, I realized that that is because I don’t live in a place like Italy or Canada right now.

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And even though it is mind boggling, I am grateful for the week I had in the sun, enjoying the culture and boisterous nature of Italy. And I realize that the quiet nature of Denmark is not all bad — just different. I think that the culture shock I experienced after being away for a week will be nothing compared to when I go back to Canada.   Regardless, Now that I have taken the chance to realize all these things, my homesickness is next to gone, and I’m able to cherish all the memories that I made in Italy: visiting Juliet’s house; visiting Venice; Visiting Vicenza; visiting Milan; adding my gum to the wall of gum outside Juliet’s house—something which I still don’t understand, but…well. I couldn’t resist adding to it— staying with an Italian family; becoming overstuffed on pizza, pasta, coffee, and, of course, gelato! Also, holding pigeons in my hand was pretty cool, too!

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The week I spent in Italy will for sure be one that I will remember, but the new friendships that I have made with the Italian students that we exchanged with, will be ones that last a lifetime! Also, the opportunity for my Danish teachers to hear my extremely high pitched squeaky laugh for the first time was an something that in itself, made the trip worthwhile. As well as my Danish classmates seeing me in another way compared to the Danish culture that they know me from. (meaning, I fit in well in the Italian culture. I am, afterall, very loud and boisterous!)

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This recent travel has allowed me to become anxious for my upcoming Eurotour (55 more days!) where I will travel all across Europe for 18 days, including a returning trip to Verona and Venice!

Tabatha Pilon is a 17 year old student from Cornwall Ontario spending a year in Denmark.   She will be writing to us  each week or as her “gymnasium” schedule allows.