Exercise 1a: Familiarisation with the aeroplane

EASA requirements:
 Exercise 1a: Familiarisation with the aeroplane:
 (A) characteristics of the aeroplane;
 (B) cockpit layout;
 (C) systems;
 (D) checklists, drills and controls.

 

Although it is not necessary to complete the entire PPL-theory course before we can start flying, we still need to have a basic understanding of how the aeroplane and it’s systems work.

Flight training can be done with almost any light aeroplane with two or more seats, and there are many to choose from. Initially it doesn’t matter much which one you choose. During this course we shall have a look at a few types and their differences.

We shall start with one of the most common of all trainers:

The Piper Tomahawk II

Specifically designed for flight training, almost 2500 were built between 1977 and 1982. Many flying clubs and -schools still use the Tomahawk today, because of it’s reliability and low operating cost.

From an instructing point of view, I particularly like its flying characteristics. Where most light trainers are build ‘extra’ stable to make it easier to fly, the Tomahawk requires proper pilot input, which makes it easier to see when you fly it the correct way, and also when you make a mistake.

In contrary to most other two-seat trainers, the Tomahawk is designed so that it does not recover from a spin without pilot input. But when the proper input is given, it will.

Note also that the Tomahawk has a better safety record than similar types.

The Tomahawk II variant has a few minor improvements, most notably the larger tires, giving a better propeller clearance, and better heating and soundproofing in the cabin.

Everything you need to know about this aeroplane is described in the POH, or Pilot’s Operating Handbook. It is a requirement for the Pilot of Command to study this manual before flight. But before you do that, let me show you some the most relevant features.

The X-plane model I am using for this class is available on Alabeo.com and the .org store

Airframe

It is an all metal (aluminium) fuselage with a ‘monocoque’ construction, which means that the strength and rigidity comes from the outer skin. Before every flight we do a “walk around” to check the airframe for damage.

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Cabin

The cabin has two doors, two seats with seatbelts and harness, and dual controls. Compared to other two-seat trainers, the cabin is spacious and there is an excellent view outside.

Wings and control surfaces

The wing is designed by NASA, specifically to give the Tomahawk its flying characteristics. On the leading edge, a pair of stall strips were installed in 1983, to make the aeroplane compliant with the new certification rules and improve its spin recovery.

It has a low-wing design. As opposed to a high wing, this provides a much better visibility for the pilot, especially in turns. Low wing aeroplanes are in principle less stable than those with a high wing, but to counter this problem, the wings of the Piper-38 are mounted in a shallow V shape. This is called a dihedral wing and increases the roll stability.

The flight controls are conventional, and connected through a cable system.

The flaps are on the inner trailing edge. They are also controlled mechanically with a Johnson bar between the pilot seats.

The flaps are normally in the UP position. They can be extend by pulling the Johnson bar between the pilots.

  • Flaps UP, gives the least drag.
  • Flaps 21° (first notch) increase both lift and drag, good for a short field takeoff
  • Flaps 34° (DOWN) Increases drag, to improve speed stability for landing.

The stall speed is only 3 knots lower with fully extended flaps.

The tomahawk has a T-tail. This design feature places the elevator outside of the prop-wash which reduces vibration in the control yoke.

control surfaces.png

Engine

The Lycoming O-235 is an air cooled, 4 cylinder piston engine which drives a two blade fixed pitch propeller. It delivers 112 HP at 2600 RPM.

Like most aircraft engines, it has twin spark plugs in each cylinder which are powered by a magneto system, making the engine completely independent from the electrical system.

There is a carburetor heat system to prevent ice forming on the throttle valve, and a mixture control to lean the mixture when flying at higher altitudes.

360

Landing gear

A tricycle, fixed landing gear supports the aeroplane the ground. The two main wheels have hydraulic disk brakes that can be operated independently. The nose wheel  has air-oil type suspension. It is steerable via a torque link, which is connected to the rudder pedals in the cockpit

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Cockpit layout

In the cockpit we find: Seats, yokes, rudder pedals and toe brakes, flap handle, 2 doors with lower and top latches, throttle, mixture, carb-heat, magnetos and a few other items.

The avionics can differ a bit in every other aeroplane. The basic instruments that must always be available for flying in visual meteorological conditions (VMC) are:

“Airspeed, Altitude, magnetic compass, RPM indicator and engine instruments and fuel quantity gauges”

Everything else is optional. Let’s have a quick look at what we have in our Tomahawk.

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  • the primary flight instruments, or “basic 6”.
    • the ASI (Air Speed Indicator) indicates IAS (Indicated Airspeed), it is measured with the pilot-static probe under the left wing.
    • The Attitude Indicator (AI) is a suction driven, gyroscopic instrument. It presents an artificial horizon and is required for flying in reduced visibility.
    • The Altitude indicator translates barometric pressure into feet. The sub-scale needs to be set to the local pressure (QNH) setting to indicate altitude above mean sea level. In the States, Inch-Hg is used, in Europe Hpa. see conversion table.
    • The turn indicator is an electric powered gyroscopic instrument and shows us the turn rate. The skid ball is a ball in a glass tube filled with oil and shows turn coordination.
    • The Heading indicator is a suction driven gyroscopic instrument. If set correctly it indicates the direction or ‘heading’ of the aircaft, and is easier to read than the magnetic compass.
  • The other instruments on the main panel are for radio navigation and will be explained in a later exercise.
  • Engine instruments
    • RPM is the rotational speed of the propeller and is a good indication of produced engine power.
    • Exhaust temperature can give us information about the fuel/air mixture ratio.
    • Oil temperature and pressure gauges are an indication of the ‘health’ of the engine.
  • The Ampere and suction gauges show the status of the two systems that power the flight and navigation instruments
  • Fuel quantity gauges should indicate if there is fuel in the tanks, and an estimate of how much.

Image: Altimeter setting conversion table

Inhg conversion
Electrical system

The electrical system is powered by an engine driven alternator and a 12v battery.
It feeds all internal and external lights, the pitot heat, the stall warning system, the electric starter motor, the electric fuel pump, the radio’s and some of the flight instruments. Electrical switches can be found on the lower side of the main panel, the circuit breakers are on the right hand panel.

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Vacuum system

The vacuum system is powered by an engine driven vacuum pump. It supplies suction power for some of the gyroscopic instruments, like the artificial horizon and the heading indicator. The system is independent from the electrical system to create redundancy.

The Pitot-static system

The airspeed indicator, altimeter and the vertical speed indicator are connected to the pitot-static system. On the bottom of the left wing you will find the pitot probe. On the aft fuselage you can find the static ports. The Pitot probe is heated to prevent blockage in icing conditions or heavy rain.

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Stall warning system

On the left wing leading edge of the wing you can find the stall warning sensor. When the wing approaches the critical angle of attack, the metal tab will be lifted by the relative airflow and a micro switch activates a buzzer in the cockpit to alert the pilot.

Carburetor heat system

The carburetor is connected to the engine, this is where air and fuel is mixed and regulated by the throttle valve to set the required power setting.

In normal operation, air enters the carburetor via the air filter. Either when the filter is blocked, or when ice forms on the throttle valve, the engine will loose power.

By selecting the carburetor heat ON, the outside air bypasses the filter and is routed past the exhaust muffler. As long as the exhaust is hot, the air warms up and prevents ice buildup.

Fuel system

The engine runs on ‘Avgas 100LL’ which is Low-Lead Aviation petrol. It is stored in two wing-mounted tanks of 15 US gallons of usable fuel each.

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A fuel selector control is located in the centre of the engine control quadrant. It can be set on the left or right tank or OFF. Fuel is pumped to the engine with an engine driven fuel pump. An additional electrical fuel pump is installed for redundancy. It should be ON for take-off and landing, and when switching the tanks.

Fuel pressure gauge, and primer are on the right panel.

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3 fuel drains, one under each tank wing tank, and one by the fuel strainer, should be opened daily and fuel checked for water or other contaminant.

A detailed description of all systems can be found in section 7 of the POH.

Checklists, drills and procedures

A procedure is a sequence of handlings that are common to a certain phase of flight.

Some procedures are quite casual, like the setup of the radios before the flight. You can do them in any order you like, as long as they are done.

Other procedures require a strict order. As an example:
For parking the aeroplane: the drill is: Parking brake SET, 1000 RPM, Landing light OFF.
When levelling off after a climb: Power, Attitude, trim.

In most cases we operate the aeroplane completely from memory, but to err is human so we need a checklist to make sure that all critical items are set correctly.

There are normal, abnormal and emergency checklist, procedures and drills.
All Emergency procedures are described in section 3, and all normal procedures in section 4 of the POH.

Note that the  ‘normal checklist’ in chapter 4 is actually the normal procedures. Most operators have made their own, abbreviated checklist for daily use. you can find the link to my variant here.

 

The introduction flight

That is enough theory for one day, now we are just going to make a short, 20 minute, familiarisation flight. During this flight I will be doing most of the work. I will be talking to ATC every now and then, and I will tell you a little bit about what I am doing.

The routing for today is the ‘standard departure’ via the south bank of the river clyde, Dumbarton and Alexandria, and the ‘standard arrival’ which is in the opposite direction via the north bank, to land back in Glasgow on runway 23.

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After take-off I will trim the aircraft for straight and level flight and give the controls to you. I will do this by saying “Your controls”. After you reply with “My controls”, you have the aeroplane.

All we are going to do is fly straight and level, and perhaps if that goes well I’ll let you do a few turns. You can’t do anything wrong, I’ll be ready to take over at any time.

When I say “My controls”, you take your hands and feet off the controls and let me fly the aeroplane again, and you reply by saying “your controls”.

Do you have any questions so far? Are you ready? Let’s go!

AIS information for Glasgow airport is available here
Piper Tomahawk abbreviated Checklist (use at own discretion)

 

OK, we are in the Aeroplane, All the pre-flight checks are complete, a flight plan has been filed, the tech-log signed, and the aircraft is positioned so we can taxi out safely.
But before we start I will give you a short safety briefing:
Make sure that your seat belts and harness are fastened throughout the flight.
Should the need arise to quickly evacuate the aeroplane, you can can release the seat belt by lifting the buckle.
The easiest way to shut down the engine is to pull the red mixture leaver all the way down. The engine should stop within a few seconds.
To open the door, open the latch on the top first, than lift the door handle. Beware of the propeller in the front of the aircraft.
Do you have any questions?
BAT switch on, radios on, I will ask start clearance to ATC.
“Glasgow Ground, G-FIOL”
G-OL pass your message”
“Piper 38 on Whiskey Apron, information Charley, request startup, 20 minute local flight, standard departure followed by a standard arrival. G-OL”
“G-OL start up approved, Information Charley correct, QNH 1021, standard exit not above 2000ft, report ready for taxi”
“Start up approved, QNH 1021, Standard departure not above 2000ft, wilco G-OL”
Radios off, ANTI COLL LIGHT ON, Before start checks:
Before start checks complete,
Prime 1, prime 2, leave the primer open. Throttle half inch, Mixture rich, fuel pump ON
outside area is clear “CLEAR PROP!”
Starter engage, close primer and lock. count for ten seconds.
Engine is ON, adjust to 1000RPM, oil pressure checked.
Alternator ON, fuel pump OFF
Avionics ON, set transponder code 7000
Set DG to compass heading
Set Altimeter
Inhg conversion
Request taxi:
“G-OL, request taxi”
“G-OL Taxi via Whiskey to holding point Yankee 1 for runway 23”
“Via Whiskey to Yankee 1 for runway 23, G-OL”
Landing light ON (Or taxi-light if you have one)
Note time departure time on your kneeboard
Outside clear, Check brakes and steering
taxi to holding point, position into wind
parking brake on, 1000 rpm, taxi light OFF
Engine run-up and before Before takeoff checks
“G-OL, ready for departure taxi”
“G-OL, via Yankee 1, line-up and wait runway 23”
“via Yankee 1, line-up and wait runway 23 G-OL”
Lookout for traffic, Transponder ON (see and be seen!)
Line up with the runway, confirm runway heading with Gyro compass
“G-OL, the wind is 300/8, runway 23 cleared for take-off, left turn out”
“runway 23 cleared for take-off, left turn out G-OL”
Landing light ON, memorise take-off time (don’t write it down!)
Stabilise engine, check T’s and P’s. brake release
Expect to give right rudder for the P-effect
Keep tracking the centre line, keep the wings level.
rotate at 53, accelerate to 70 and trim.
At 1500ft, Attitude Power Trim to level off
Ok I will talk you though it are you ready? “your control”
Keep the attitude of the aeroplane just as it is, by making small adjustments in up or down, by raising or lowering the nose of the aeroplane. and keeping the wings level.
To turn the aircraft, gently bank to the left or right and keep the nose on the horizon at the same time.
follow the M8 untill we pass dumbarton, follow the river leven to Alexandrie
“Tower, G-OL, passing Alexandria, request rejoin via standard entry”
“G-OL, approved, clearance limit is Erskin bridge, not above 2000ft.”
“Cleared to rejoin, Limit is Erskin bridge not above 2000ft, G-OL”
Make a 180 turn to the right over Alexandria return Dumbarton. There turn left, follow the north bank of the Clyde to the Erskin bridge.
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“G-OL, number one, report final runway 23”
“Wilco G-OL”
After the Erskin bridge, descent to 700ft along the north bank of the river clyde.
Reduce power to ~1500 RPM, set carb heat ON.
Before the base turn, reduce the speed to 80 knots.
When the speed is below 89, set flaps 21 degrees (first notch)
“G-OL, final runway 23”
“G-OL, Wind is 240/7, runway 23 cleared to land”
“23 cleared to land G-OL”
On final, reduce speed to 70 and set flaps 34 degrees (flaps down)
complete the landing checklist
Fly the aircraft until you are just a couple of inches above the centreline. reduce the power to idle and try to stay in the air for a few seconds to bleed of some speed. after about two seconds, hold the pitch attitude and let the plane settle down on the runway.
Always land the main wheels first, keep the nose wheel about an inch off the ground for about a second, then let it settle down softly. keep a light back pressure until you are at taxi-speed.
Be gentle on the brakes, there is no anti-skid and you don’t want to lock the wheels.
“G-OL, vacate to the right, taxi to the club, monitor ground on 121.7”
“to the right, monitor 121.7 G-OL Cheerio!”
After vacating the runway, set flaps UP, Fuel pump OFF, transponder ON, remember the landing time.
Taxi back and park into wind if possible.
Set 1000 RPM, parking brake set, landing light OFF
Switch off the Avionics,
Magneto dead cut
Set idle power, then mixture off.
When the engine is off, magnetos off, ANTI COLL LIGHT OFF,
BAT and ALT switch OFF
Note the landing and on-blocks time and tacho
consult the post landing notes on the checklist.
Let’s secure the aircraft, and then go inside for a coffee and a de-brief. Do you remember how to open the door?

De-briefing

So, this was exercise 1a. Have you enjoyed it as much as I did? I sincerely hope so. So a quick review of what we have done.
We have familiarised with the aeroplane and some of its characteristics, and some of the most essential items in the cockpit.
After a quick safety brief, we started the engine and prepared the systems for flight.
The best way to operate an aeroplane is to do everything from memory, and then use the checklist to make sure you didn’t forget any critical items.
You may also have noticed that I had to obtain clearances from ATC from time to time, that is because this is a controlled airport.
But even though we received a clearance to line up, we had a good lookout before entering the runway. This is an example of good airmanship. We are working with humans and humans make mistakes. but as long as we stay vigilant we can keep flying safe.
After a quick engine check we took off, and climbed to an altitude of about 1500ft.
To level off in the cruise, the Mnemonic was Attitude, Power Trim. So first the nose of the aircraft was lowered into the cruise attitude, the power reduced and the control forces balanced out with the trim.
To make a turn, we have a good lookout first, and then all we have to do is gently bank the aircraft to the direction we want to go, and keep the nose of the aircraft on the horizon. A little bit of back pressure on the yoke is required to prevent the aircraft from losing altitude.
To start the descent, the mnemonic is Power, Attitude, trim. reduce the power, set the nose in the descent attitude and trim the control forces away.
Then we landed back on runway 23 and taxied back to our GA apron.
I can imagine that the first time flying a light aeroplane can be a bit intense, and that you may not remember everything perfectly for the next flight, but that is normal. For this reason specifically, exercise 1 is split into A and B, and exercise 1B is almost an exact repetition of what we have done today.

Homework

before the next session:
In review of today’s flight, have a look at the POH, casually read though chapter 7 and the expanded procedures in chapter 4. See if you recognise anything from what you have experienced today.

In preparation for the next flight, have a look at chapter 3, the emergency procedures. For now it is sufficient to glance through it, a deeper study will be required before exercise 14.
Piper Tomahawk POH is available here
I hope you have enjoyed the whole experience, If you have any burning questions, feel free to ask. Thank you for flying with me today and I hope to see you soon for the next flight.

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