Highest fail rate - Forced Landings - Why?

I finally went back flying after a few weeks' absence...had a good reason mind you. I'm now a father!
Still can't believe it sometimes. I'm a dad of a most beautiful boy. He was born just a few weeks ago, his name is Niko and I can't wait to take him flying.

The day was perfect and my instructor decided to go over all the main exercises including steep turns, slow flight, forced landings and stalls. Considering the lengthy absence I did pretty well. I think.

I do however want to dedicate this post to forced landings. From my research it appears this is one of the 'most failed' exercises during the flight exam...so why?

The simple sequence goes something like:

1. Carburetor heat on (if you have one)
2. Set glide speed
3. Pick a field to land and plan your approach
3. Cause check

• Fuel (pick the tank with most amount of fuel)
• Ignition (on)
  
• Mixture (rich)
  
• Carburetor, Alt air. Throttle to full

4. Restart
if you fail
5. Radio - Mayday – Squawk 7700
6. Brief Passenger(s)
7. Try again. Secure engine (Ignition off, fuel off, etc)
8. Fly
9. Unlatch doors before touchdown, master switch off on final
10. Land safely

Only 10 steps, seems simple enough. So, what's the deal?

I know I oversimplified but where do you think is the issue ?

What do the flight examiners have to say about this exercise?

The forced landing item is not only about gliding to a point, it is also about managing an emergency situation, making correct decisions and following prescribed procedures that lead to a successful approach and landing.

It's all about you being able to manage. Key points according to the examiners' manual?

1. Pick the field and stick to it- I know this may sound a bit daunting especially when you are at 3000 feel AGL and you can't make out much more than a house, but I after a few times practicing this exercise I noticed that it is better to pick an 'ok' field (rather than the 'perfect' field) that looks level, without too many obstacles and hopefully into the wind and not into the sun:) ...another tip, pick a field you know you can make. How? By estimating your glide distance - here is what I recommend. By the way, in most cases if you change your mind during the exam about your pick, you fail!
   
2. Control/Approach - translates to 'make the field' - this is where your glide estimate comes in handy. It also helps to know your approximate altitude AGL so you can arbitrarily pick a point at which you need to start your base turn and final approach. The recommended point is usually 1000 AGL when you beam the touchdown point threshold. Tip - check out the map and the closest obstacle so you can calculate the ground elevation. Then, hands on flying as you practiced many times before.
   
3. Cockpit Management - remember your safety checks including your 'cause check' above and overall good airmanship
   

It does not appear complicated but I believe based on my own experience, many make the mistake to over think this exercise including the choice of the field...! My advice? Trust your experience. There is a reason they make you practice this one over and over again.

Here is a good article I've found on the web from New Zealand that focuses on forced landing .

What are your experiences? Make sure to comment below.

V- Speeds

Velocity speeds are universal terms used to define important airspeeds of the aircraft. You want to know at what speed you will clear the tree that is in front of you...:)

The following V-speeds and their definitions you need to know for the PPL exam. I tried to summarize them as they appear on the airspeed indicator as well as importance.

Indicated on the Airspeed indicator:

• V_{SO -} Stall Speed with landing configuration, that is flaps out (could stand for the "O") and landing gear down. The VSO is indicated at the bottom of white arc
• V_S - Stall Speed with a "clean" aircraft configuration. i.e. No flaps. Bottom of the green arc
• V_FE – maximum flap extension speed – the top of the white arc on an airspeed indicator. Flaps should not be extended beyond this airspeed.
• V_NO – safe normal operating speed – the beginning (bottom) of the yellow arc or top of green arc on an airspeed indicator. One should only fly over this airspeed in smooth air conditions.
• V_NE – never exceed speed – indicated by a red line on the airspeed indicator. This speed is the maximum allowed to insure structural integrity in smooth air only.

Magnetic Dip, Not the Macho Nacho Dip

Most everyone loves the nacho dip but most pilots don' like the magnetic one....Find out why below.

I'm sure you are all familiar with the compass however for the PPL exam and when you are flying you need to know about a couple of its tendencies.

One of them is the Magnetic dip which results from the tendency of a magnet to align itself with lines of earth's magnetic force. These lines of force are not parallel to the surface so in the north end, the compass needle will point down on the northern hemisphere (positive dip) or up on the southern hemisphere (negative dip).





One sample exam question you may encounter may be:

Q . When operating in the northern hemisphere, one can expect a direct reading compass to _____, when turning from a heading of 085 degrees to 115 degrees.

1. lead
2. show little or no error
3. lag
4. dip

Solution?
Let's look at some useful techniques to understand and remember.

Turning Errors
When turning from southerly headings the compass tends to lead, meaning the compass indicates the direction before the aircraft. When turning from northerly headings the compass tends to lag meaning the aircraft is turning in advance of the compass indication.

A good mnemonic to remember :

SAND
S - Southerly heading
A - Compass to Advance (lead)
N - Northerly heading
D - Compass to Delay (lag)

or

OSUN
O - Overshoot
S - South
U - Undershoot
N - North

I find SAND is easier to remember, but the choice is yours. Below is an image I found that shows the magnetic dip at work.



These errors are most noticeable near the north and south poles and non-existent at the equator. Therefore, these errors are observed when turns are initiated from northerly or southerly headings, and least when turns are initiated from easterly or westerly headings.

Note: These effects are opposite in the southern hemisphere.

Acceleration/ Deceleration Errors
Acceleration and deceleration errors are apparent on the compass reading most noticeably on easterly or westerly headings. These errors are non existent on headings of north or south.

Acceleration will cause the compass reading to indicate a turn towards the north.
Deceleration will cause the compass reading to indicate a turn towards the south.

A good mnemonic to remember :

ANDS

A - Accelerating
N - Northerly indicating error
D - Decelerating
S - Southerly indicating error



Let's get back to the question...

My recommendation? Deconstruct it:

• What is your heading? - In this case Easterly (85 degrees).
• What is the action? In this case a Turning slightly to the South (115 degrees)
• Do the rules apply?
  

Turning Error? SAND? - in this case - No! We are turning but we are not on a Northerly or Southerly heading.

Acceleration/Deceleration Error - in this case - No! - There is no evidence of acceleration or deceleration in this example

The Answer: show little or no error.

You may be tempted to pick an answers that suggests magnetic errors ( I was) but please be careful as in some cases no error will be observed. The lesson? Make sure you understand all the information given to you before you solve the problem.

It's all about the balance

For this post I'm going to assume you understand the concept of weight and balance in aviation. You can learn the basics by reading and watching the following: read here and watch this video.

Instead, I'm going to focus on what you need to know for the exam.

You can expect the following types of weight and balance questions in the exam:

A. Concerning aeroplane "x", one could _____, to bring the aeroplane back into the centre of gravity moment envelope.

1. remove weight from the aeroplane
2. move weight forward in the aeroplane
3. move weight towards the back of the aeroplane
4. do none of the above

B. What is the location of the CG, in relation to the datum, for aeroplane "x"?

1. 35 inches aft the datum.
2. 44 inches aft the datum.
3. 101 inches aft the datum.
   
4. 70 inches aft the datum.
   

C. The load details for aeroplane "x", indicates that this aeroplane

1. is within the weight limits for the utility category only.
2. is within the weight limits but is not within the C of G limits.
3. exceeds both the weight limits and the C of G limits.
4. is within both the weight and the C of G limits.

in most likelihood, you will be provided with three things to work with to solve the following problems:

1. Sample loading scenario
   
2. Loading Graph
3. Centre of Gravity Moment Envelope Chart

The starting point is your sample loading scenario calculation that will have incomplete portions that you will need to look up in the loading graph. You may be given the weight of the passenger and pilot but then you need to use the loading graph to find the corresponding load moment/1000 (pounds-inches). You will repeat this to find the total weight, CG and arm of the loaded plane.

Sample of the materials you will be provided with:




Below is a sample Loading Scenario.

The formulas you need to know are:

Moment 1000/lb-in = Weight * Moment Arm /1000

Hence: 51 = 1365 * 37/1000

Load Details	Weight	Moment Arm (inches)	Moment 1000/lb-in
Basic Weight (includes full oil/unusable fuel)	1365	37	51
Usable fuel at take-off	230	52	12
Pilot and Front Passenger	360	38	13.5
Two rear seat Passengers	282	71	20
Baggage	50	80	4
Total	2287	44	101
Moment arm inches from datum is (CG)	44

Let's solve the problems then:

Solution A.
Using the total of 2287 pounds and 101 as the Moment 1000/lb-in, you ensure both points are within the envelope. Using the chart above you will see both the weight and the C of G (in this question referring to the moment) are within limits so 4 is the answer. If they are not however, use the rule below to put it into balance:

The CG location is above the envelope - weight must be removed from the aircraft.
The CG location is ahead of the envelope - weight must be moved back in the aircraft.
The CG location is behind the envelope - weight must be moved forward in the aircraft.

So, if the moment was 80 instead of 100 at the same weight, the weight would have to be moved to the back in the aircraft.

Similarly, if the moment was 115 instead of 100 at the same weight, the weight would have to be moved forward in the aircraft.


Solution B.
This one can be tricky as one of the answers is 101, which you may think is the answer...Nope, 101 is the moment 1000/lb-in not the arm which is the distance in inches aft the datum.

The answer here is 44 as it is calculated by the sum of the moment arm divided by the total weight.

hence: 101,000/2287 = 44


Solution C.
Ensure that the total weight of the plane and the total moment where these two points cross each other are charted within the 'envelope' . In the case above with weight of 2287 pounds and moment of 101, the plane is within the envelope hence the answer is 4.

One tricky part about this question can be when the airplane is within the weight limits but is not within the C of G limits. An example of this would be a plane with weight of 2400 pounds and CG (moment 1000/lb-in) of 90. If you think about it, the max allowable weight for his plane is around 2550 lbs, hence 2400 is still below that. The CG however is too far left. The weight would need to move to the back of the plane to just over 100 for it to balance.

If you know how to answer the above questions, you will not have problems during the exam.

In addition have a look at this cool weight and balance calculator here.

UTC vs LMT

In the PPL exam in the NAV section you may encounter questions that require you to convert local times to universal times or vice versa. Be careful when you encounter them and ensure you know what is being asked!

Here is a sample question:

The time UTC is 0100Z. What time is it at a location 60 degrees longitude west of Greenwich England?

1. 2100LMT
2. 2100Z
3. 0500LMT
4. 0500Z

Ok, so what do we know about the time zones?

Well, standard time zones are made up of Earth's 24 equal parts bordered by meridians each 15° longitude apart.

So, in the example above, 60 degrees divides nicely by 15 to give you 4, meaning you are 4 hrs west of Greenwich England (that of course happens to be the location of the the mean solar time at longitude 0° also called the Prime Meridian. )

When converting LMT (local mean time) to UTC (universal coordinated time), remember:

• East is least - subtract one hour for every 15 degrees of longitude, if the location is east of the prime meridian.
• West is best - add one hour for every 15 degrees of longitude, if the location is west of the prime meridian.

Using the rule above you may be compelled to add the 4 hrs to 01:00 as west is best? NOPE...

Please note that above the time given is 1 o'clock UTC, so you do not need to convert to UTC but rather to LMT.

Therefore, you use the reverse rule of the above to convert from UTC to LMT.

100 UTC minus 4 HRS = 2100 LMT (or 9PM)

Viola, the answer is 1.

Here is a great time zone map for your review

Test your knowledge in this example:

A location that is located 45 degrees longitude east of the prime meridian has an LMT of 1000. The Universal coordinated time would be

1. 0600Z.
2. 0700Z.
3. 1000Z.
4. 1300Z.

Answer?





1000 minus (east is least) 3 hrs (45 divided by 15) = 700Z (UTC)

Therefore: 2