Friday, October 31, 2008 - 13:14:25 ET

The CRFI, Part 2

Let's take a look at an example METAR with CRFI data in it:

CYFB CRFI 17/35 -22 .34 0201190630

In order, the block of data contains:

• Airport/Station Ident
• CRFI Indicator
• Runway
• Temperature
• CRFI value
• Date/Time reading was taken

So the CRFI for runway 17/35 is 0.34. We can use this value now to figure out how much extra runway we may need on landing. Let's take a look at Table 1 in the AIM, Section AIR 1.6.6. You can also find the CRFI charts in the CFS.

If your performance calculations indicate that you will need 2000 feet of runway to land, with a CRFI of 0.34, you will in fact need 4170 feet. We used table one because the type of aircraft we're flying does not have discing or thrust reversers. One thing to note. These distances assume that you're wheels do not lock/skid when you apply brakes.

It is important to do all your performance calculations first, then use the table to find out the extra distance needed due to the CRFI. It's not recommended that you extrapolate the data in the tables either. You should also round down to the nearest CRFI value.

Table three allows you to figure out your maximum allowable crosswind. It's your standard cross-wind chart/calculator with the addition of CFRI values along the top and bottom. Looking at the chart, you can see that the maximum allowable crosswind for a CRFI of 0.34 is approx 12knots. At that speed and above, you may be unable to stay on the runway as the wind will blow your aircraft off to the side as there is insufficient friction on the runway to keep you in place.

In my next post, I am going to talk another winter tool that complements the CRFI. It's the runway surface condition report! Stay Tuned.

Comments (2) | Permalink | Category: Airmanship, Ground School, Training

Thursday, October 30, 2008 - 13:39:11 ET

The CRFI

Back in January of 2007, I breifly talked about the Canadian Runway Friction Index (CRFI). With the recent winter-like weather in Southern Ontario I figured this would be a good time to go into more detail.

Most progression in aviation safety is usually prompted by a previous accident or incident. The creation of the CRFI was no exception. A Fokker F-28 slid off the end of the runway at Dryden in March 1989, killing 24 of the 69 persons on board. An inquiry was created and the Dryden Commission stressed the need to come up with a way to measure and apply corrective measures for differing runway surface conditions.

Transport Canada teamed up with NASA (along with French and Norwegian authorities) to come up with a way to measure runway conditions. The study was started in 1996 and it's aim was the following:

• to study methods of friction measurement and define an International Runway Friction Index (IRFI) for worldwide use;
  
• to establish an international methodology whereby a common indication of runway conditions can be established worldwide; and
  
• to study the operational performance of aircraft on contaminated surfaces and establish a relationship with the harmonized index (IRFI).
  

Tests were performed in North Bay, Ontario, Wallops Flight Facility in Virginia, Oslo Gardermoen Airport, Munich and at Erding Airbase. Tests were also conducted at Prague Airport in the Czech Republic and at the New Chitose Airport, hosted by the Japanese civil aviation authority.

A database was developed and made available that contains test data from over 38,500 runs with 44 devices of 14 different makes. Test surfaces include at least six different ice conditions, packed snow, loose snow from .25 mm to 100 mm, and over 30 wet and dry surfaces. Test temperatures range from -25°C to +10°C.

In the end, two standards were created.. The CRFI as well as an international version called IRFI.

A survey in 2001 was released to over 3,000 airline transport pilots requesting their input on how they use the CRFI. Here are some of the findings:

• In winter 2000-01 about half the pilots reported either remaining airborne until runway friction improved or diverting to another airport.
  
• Reductions in weight prior to take-off or while en route were far less common.
  
• Friction values need to be updated more frequently, particularly at small airports, and steps taken to ensure readings are current and have been updated when significant changes in conditions occur.
  
• Over 20% of pilots of large jet aircraft had not received any formal training on the use of runway friction information, and only half had received training in the previous 12 months
  
• For landings on runways that are icy or covered with compacted snow, most pilots apply a 15% increase in landing distances, which is a requirement for many aircraft on wet runways.
  

Even for light aircraft, the CRFI is still an important part of your flight planning. One thing I've noticed, especially at Buttonville, is the lack of updates to the reported CRFI. In my experience the CRFI has only been updated once, during the morning, and that's it. I'm glad they do it anyways.

Tomorrow I will talk about how to apply the CRFI to your flight planning. How to use the available graphs as well as how to calculate any increase in take-off and landing distances. Stay Tuned.

References: http://www.tc.gc.ca/TDC/publication/tp13361e/13361e.htm

Comments (2) | Permalink | Category: Airmanship, Ground School, Training

Friday, June 13, 2008 - 15:50:09 ET

Calculating Legal Night

One thing you need to do that wasn't really taught (to me) was how to calculate when you're flying at night (or Legal Night as us pilots like to call it).

This is important for a few reasons:

- If you don't have a night rating, you need to know when you need to be wheels down and engine off.
- If you do have a night rating, then you need to know when you can log your hours as night.
- I'm sure airport operators needs this information for when to turn various lighting systems on or off.

First, lets define when nighttime for the purposes of aviation and your log book starts and ends.

GEN 1.6.2 Says:

In the morning, Twilight begins when the sun is 6° below the horizon ascending, and ends at sunrise, approximately 25 minutes later. In the evening, Twilight begins at sunset, and ends when the sun is 6° below the horizon descending, approximately 25 minutes later.

Who did what in the where now?!? In other words...

Dawn is 25 minutes before sunrise, Dusk ends 25 minutes after sunset.

So we know when Twilight starts and ends for both the morning and evening. How does that apply to finding out when it's nighttime? We need to turn to CAR 101.01 for that:

"night" - means the time between the end of evening civil twilight and the beginning of morning civil twilight; (nuit)

So in other words, "night" for the purposes of aviation starts 25 minutes after sunset and 25 minutes before sunrise.

Great! So uhmm.. how do I find out when sunrise and sunset are? Here are a few ideas:

- Hand held (and probably aviation) GPS units have that information in a menu someplace.
- You can ask ATC (especially if its an FSS you're talking to)
- You can use the graph found in the AIM.
- You can use the internet, specifically the NRC website.

No matter what way you use to get the information be sure you do the following:

- If you are given values for sunset and sunrise, add 25 minutes to the sunset time, and subtract 25 minutes from the sunrise time to give you legal night.
- If you are given values for civil twilight start and civil twilight end, then do not apply any correction to the time.

This is another reason to keep track of your start-up and shut-down times. As this can occur on a day/night boundary. Ie, you need to log your 2 hour flight as 1.1 in day and 0.9 in night.

Comments (4) | Permalink | Category: Air Law, Ground School, Training

Friday, April 4, 2008 - 13:26:25 ET

Airports, Aerodromes, and Grass Strips

A friend of mine mentioned that it would be cool to have "a million dollars" to have his own airport. I told him that all you need is space to land an airplane and you can do just that, legally.

Without referencing anything, I told him that you are allowed to land on private property as long as you have permission. If you own the land, then there should be no question as to the legal ramifications of landing an airplane on your parcel of land.

The conversation ended there but I decided to look further into things like getting your "airport" listed in the CFS.

Let's start with the most basic of aerodromes. A grass strip on your farmland. It's literally just a 3000 foot by 50 foot strip of mowed grass. Just enough to get your 172 airborne and land safely.

Since the winds in Canada are primarily from the west, your strip is orientated in an east/west direction. Runway 27/09.

You own the land. Therefore you have the right to land and take off your aircraft from that grass strip. Your friend asks you if he can use it to, you say "yes". He is now legally allowed to land on your grass strip.

After a summer of take-offs and landings at your grass strip, your neighbour starts complaining that what you're doing is illegal.

CAR 602.14(2) states that you are allowed to fly "low" and close to people or property as long as you are conducting a take-off or landing. As long as you're not buzzing your neighbours house, what you are doing is totally legal.

Yes, your grass strip is technically an "Aerodrome".

The following year you've added a windsock so that you can tell which direction the wind is coming from. You also would like to add your aerodrome to the CFS so that fellow pilots can find information about your grass strip.

Since there is a windsock now, the minimum requirement for registering an aerodrome, you put your request in to the Minister to add your aerodrome to the CFS. CAR 301.03 outlines what minimum requirements are needed before you can register your aerodrome.

Technically, you don't even need a windsock if you are able to determine the wind direction by means of smoke, or ripples in water.

Your little grass strip is now a registered aerodrome. It will appear in the CFS and on aeronautical charts.

I have noticed a few such aerodromes in the CFS. Particularly New Liskeard (CPX3) aerodrome. This aerodrome interests me because it is close to Cobalt, Ontario. The town my girlfriend grew up. I think it would be cool to visit her family one day by plane.

Anyways. Pretty much anyone can have a registered aerodrome in Canada. If you'd like to run an airport, well thats a different cup of tea.

Registration means it appears in the CFS and is registered with the Government as an aerodrome. The registration of an aerodrome with Transport Canada is handeled by each regional office of TC. The registration form for an aerodrome in Ontario can be found here.

Certification means that it is an airport and compiles with CAR 302. this includes things like having an Airport Operations Manual, application for a certificate, and minimum obligations of the airport operator.

Comments are welcome.

Comments (3) | Permalink | Category: Air Law, Ground School, Interesting Things, Training

Saturday, December 23, 2006 - 13:29:18 ET

Ground Briefing Study Lesson #1

Documents and Airworthiness
Q: With respect the Air Regulations, what documents are required to be on board for every flight.
A: Certificate of Registration, Certificate of Airworthiness, Weight and Balance Report, Journey Logbook, POH, Licences (radiotelephone medical, and pilots licence), Interception Orders, proof of insurance.

Certificate of Registration
Q: What does the Certificate of Registration tell you?
A: Gives the nationality and registration mark, aircraft manufacturer, model and serial number, the purpose, name and address of the owner, owner registration date, certificate issue date, and signature for the Minister of Transport.

Q: How long is the Certificate of Registration valid? What invalidates it?
A: Remains valid as long as the ownership does not change, or the owner's address does not change. It becomes invalid when the aircraft is destroyed or taken out of service permanently.

Q: How long does the owner of an aircraft have to notify the Minister of Transport for a change of address?
A: 7 Days

Q: What is the procedure with respect to the Certificate of Registration when the aircraft is sold?
A: To effect a change of ownership, the reverse side of the Certificate of Registration must be filled out and mailed to the Minister of Transport within 7 days.

Certificate of Airworthiness
Q: For how long is the original Certificate of Airworthiness valid?
A: Indefinitely, if the aircraft continues to meet the conditions under which it was issued, that is, as long as the aircraft is maintained in accordance with the requirements of the controlling agency.

Q: What temporarily invalidates the Certificate of Airworthiness?
A: Failure to comply with Airworthiness Directives, failure to do required maintenance, an action that contradicts the POH, minor or major accident, snag written in the journey logbook.

Q: How often must the Certificate of Airworthiness be re-validated?
A: Once a year of every 100 hours, whichever comes first.

Q: How is it revalidated?
A: By submitting an Annual Airworthiness Information Report

Q: Is a Certificate of Airworthiness issued for amateur-built aircraft?
A: No, Amateur-built aircraft are issued a Flight Permit

Weight and Balance Report
Q: Define Basic Empty Weight (BEW)
A: BEW includes: Weight of the standard airplane, all optional equipment, full oil.

Q: Define maximum takeoff weight
A: Maximum takeoff weight is the maximum weight approved for the start of the takeoff run.

Q: How does the maximum take off weight differ from the maximum ramp weight?
A: Maximum ramp weight includes the fuel that will be used for start, taxi, and run-up. Therefore, as a result of the fuel already burned, maximum takeoff weight will be less than maximum ramp weight.

Q: Who prepares the Weight and Balance document that must be carried on board?
A: The weight and balance document is prepared by the manufacturer of the aircraft.

Q: Show the actual Basic Empty Weight and Gross Weight for the test aircraft.
A: Produce, for inspection, the weight and balance report for the aircraft actually used for the flight test test.

Q: What is the difference between normal and utility categories?
A: The utility category is solely for the purpose of training pilots in certain flight manoeuvres and, therefore, is usually subject to some restrictions. The normal category, maximum gross weight operations are permitted, but certain manoeuvres, such as spins and steep turns, are prohibited.

Q: What can the pilot learn of the categories for which the aircraft is approved as well as any related limitations?
A: Take a look inside the POH

Q: Is an aircraft considered airworthy if overloaded? Why?
A: No. Compliance with weight limitations is part of the airworthiness validity.

Q:How often does an aircraft have to be re-weighed?
A: If a change in weight of more than 2% of the empty weight has occurred.

Q: What important information is found on the original Weight and Balance Report that will not be found elsewhere?
A: Date of manufacture of the aircraft, the actual unusable fuel, the amount of full oil.

Comments (3) | Permalink | Category: Air Law, Ground School

Wednesday, September 27, 2006 - 21:29:14 ET

How to intercept a NDB track

I am going to illustrate how to intercept a NDB track using MS Flight Simulator 2004 in a perfect world (no wind to worry about).

There are certain times that you will need to track to a NDB at a particular heading. This is mainly used in two situations:

1. You are using NDB (LF/MF) airways.
2. You are using a NDB approach into an airport.

In this example we want to intercept the Buttonville (KZ) NDB at 150°.

Step One - Tune and Identify
The first step involves tuning your nav radio to the Buttonville NDB frequency. You can find this frequency on any chart (VTA, VNC or an IFR LO chart). It is also located in the CFS. Tune your radio to 248kHz (1) and pull the volume knob to listen to the Morse code (2).

If you don't hear any Morse code, then the station is un-serviceable and cannot be used for navigation. If you hear Morse code and it is not what is to be expected, double check your frequency.

Step Two - Parallel Your Track
Once you have the NDB station tuned. You need to find out at what heading you need to fly in order to intercept this track.

Turn your airplane to a heading of 150° (3) and note that the bearing to the NDB station is 50°^[1] to the right (4).

The rule of thumb to use is to add 30° to your bearing to station and turn that many degrees towards the ADF needle. There is one exception though. You never want to turn more than 90° so you add 30° to whatever your ADF needle shows to a maximum of 90°.

In this case 30°+ 50° = 80°

Step Three - Intercepting The Track
Turn 80° to the right. 80° + 150° = 230° (5) You will notice that the ADF needle has moved(6). You want to keep flying this track until the needle has moved 80° to the left (when it reaches 280°)

Step Four - Flying To The NDB
When the ADF needle gets 80° to the left (when it shows 280°) it is time to turn!(7) Turn to the heading that you want to intercept the NDB at, which is 150°(8)

Just keep on this heading and you will cross over the NDB. You will notice that the bearing to the station is 0° (because the needle is pointing to north)(9)

How do you know when you've crossed over the NDB? When the needle swings 180° and points behind you.(10)

^[1] Note: When I originally performed this exercise I noted the bearing to station in step two as being 050° instead of 055° This is why the ADF needle in figure 9 is pointing to 005° instead of 000° This error is also noted on my ground track as I don't fly directly over the station.

Comments (0) | Permalink | Category: Ground School, Instruments