We have all been sitting by the window waiting to board our flight at some point and see a pilot walking around the aircraft looking at stuff, but what are they actually checking for? Then, as you board the plane both pilots seem to be doing things in the cockpit, what are they doing in there?

Before taking off in any aircraft, pilots have to ensure the aircraft has been released by the maintenance engineers, complete visual inspections of the aircraft, test emergency and safety systems, configure the GPS and instrumentation, check the weather, routing, and weight & balance.

No matter if the aircraft is a small Cessna, Helicopter, Corporate/Private Jet, or a Boeing 747, every pilot has to complete a series of actions to ensure the aircraft, crew, and cargo are all fit for flight.

Once a pilot is satisfied that everything required for the flight is as it should be only then will the flight commence. Read on to find out more detail about many of the things the pilots do before takeoff…

What Paperwork Do Pilots Check Before Takeoff?

Oh yes, the lovely paperwork! No matter what your job is there always seems to be an endless amount of paperwork, but luckily, many companies have now incorporated the documentation and paperwork into digital software making the task a little simpler.

As you can imagine there can be a lot of paperwork involved in aviation and each part plays a role in the safety net used to identify hazards or problems before they occur.

Aircraft Logbook

Every aircraft has a logbook. This is a mandatory book that documents every flight, the crew names, flight times, landings made, any additional information required by the company, and any maintenance issues that have previously occurred and have either been fixed or deferred while waiting on parts.

This is the pilot’s first check. If maintenance has not released the aircraft for flight, then a replacement aircraft needs to be used. Once the pilot signs the logbook for the day’s flight they have then taken responsibility for that particular aircraft.

This only works outside of the major airline world as a paper logbook would be impossible to track with the aircraft and would become lost, I guarantee it! To cover this, each airline carrier issues the same information but in a digital format called a Flight Release. This allows the pilot to check all the relevant information regarding the aircraft and sign for taking responsibility.

Maintenance Release

I want to expand a little more on the maintenance release as it can be quite a big issue if not inspected diligently. Whenever a pilot detects a problem with something on the aircraft they will fill out a section in the logbook, or company computer system detailing the issue. This allows the maintenance department to look into the fault and hopefully fix it right away, or they can defer the fault for a set period of time.

Depending on what the problem is, maintenance can defer items for 30, 60, or 90 days, or if it cannot be deferred, the aircraft is grounded until the issue is resolved. The maintenance manuals issued by the aircraft manufacturer will give guidance on the deferrals.

It is the pilot’s job to ensure the aircraft has not been grounded, the aircraft is still within the deferred time limit, and if the item has been deferred, its lack of function does not conflict with other items or systems on the aircraft.

Large, complex aircraft have an MEL (Minimum Equipment List). This lists the items which can be non-functioning for a flight, lists any conflicting items affected by the non-functioning part, and gives guidance on certain flight regimes that cannot be completed while the broken part is out of service.

This last part is of particular importance to the pilots because if they intend to use that part as part of their intended flight it could become a distraction in the cockpit wondering why its not working because they didn’t see the paperwork.

Company Memos

Many large aviation companies will issue memos throughout each month. Some of these memos can be additional inspections required by the manufacturer, changes to company operating procedures or policies, or even the results of incidents that the company may wish to bring awareness to for its pilots.

Most memos are there to help increase safety and are good to be read, however directions issued from the manufacturer that need mandatory compliance will need to be done by the pilots to ensure the aircraft is fit for flight. Flying an aircraft while not complying with a mandatory company memo could lead to disciplinary proceedings or worse!

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Weather

Because aircraft fly in the same area as weather the pilots need to know about the weather for all phases of the intended flight. The weather at the time of takeoff, the weather en route, the weather at the destination, and the weather at any alternate landing destination must all be checked before and sometimes during the flight too.

Severe storms, reported turbulence, heavy icing, wind, cloud heights, and visibility are just some of the weather factors that need to be ascertained by the pilot before the flight commences.

Mother nature ALWAYS wins and as pilots, we have to respect her and if the weather during any part of the flight goes beyond personal and company limitations then alternate arrangements, routings or destinations may need to be changed or the flight postponed or canceled altogether.

NOTAMS

Notice To Airmen (NOTAMS) are issued by the FAA to alert pilots to information that could affect their flight. No matter how big or small the aircraft, NOTAMS applies to all pilots.

NOTAMS can be issued for things like runway closures, navigation equipment and airport lighting systems down for maintenance, a new crane on a building near an airport, blasting at a mine site, wildfire airspace closures, large firework displays, temporary airspace closures for when the President is in town etc.

Planning to arrive at an airport with only one runway that is closed for maintenance could be a bad scenario if low on fuel. This is why pilots should be checking the NOTAMS before every flight.

Flight Plan

This is just what it sounds like – It is a plan of the flight. These are completed by the pilots of smaller aircraft or by the dispatch department of large airlines.

They consist of the details of the flight – the departure and destination locations, the routing, altitudes, and headings to be flown, fuel onboard, names of the flight crew, number of passengers on board, any dangerous cargo on board, survival equipment on board, aircraft registration and coloration, etc

They can be as detailed or sparse as pilots wish but the main reason for a flight plan is that it needs to be filed with the FAA so that the flight can be placed into the system for its requested flight time slots, as these are limited, and the plan then activates search and rescue procedures if the aircraft fails to arrive at its destination.

Most aviation companies will track their own flight’s progress using satellite tracking systems but any flight leaving the country or wanting to enter military airspace will need to have filed a flight plan before the flight to avoid Uncle Sam’s fighter jets arriving on your wing!

What Do Pilots Check On An Aircraft Before Takeoff?

Once all the paperwork is in order, both the pilots and ATC know where they are going and all the aircraft and airspace is functioning correctly it is time to now go and get the aircraft ready.

Daily Inspection – DI

This is an inspection of the entire aircraft that is required every day before the aircraft flies. It is aimed more at small, private, or commercially operated aircraft rather than airlines.

This DI requires the pilot to walk around the aircraft and lift every cover panel to look for fluid leaks, broken hoses, burn marks, broken wires, fluid levels, structural cracks, bent parts, and holes in the fuselage – essentially anything that could compromise flight safety.

This visual inspection should be a good habit that pilots have, as many DI’s have caught an issue that would have been fatal if the aircraft took off. The DI is something I do on my helicopter before each flight of the day and it only takes about 30 minutes, but the peace of mind I have is complete.

Turnaround Check

This is the inspection that you will see pilots at the airport doing while wearing their Hi-Vis jackets.

The turnaround check is done by all pilots, myself included and it comprises a walk around the aircraft visually looking for anything that happened during the last flight that may need addressing before lifting off again.

This will be things like fluid leaks, low tire pressures, chafing wires or hoses, birdstrikes, and loose or open cowls. Basically anything obvious that can be seen by the pilot while walking around.

In my case, I load the passengers, close their door, ensure the ski basket contents are secure and closed and that every cargo door is closed and locked all while I walk the full aircraft back to my door. Then I get in.

You would be surprised how many backpacks or water bottles I have found left on the ski basket!

Aircraft & Avionics Setup

Depending on the aircraft, the amount of systems and things that need to be set up varies wildly! In a large commercial jet for instance the pilots will need to set up many items.

To do this they will run down their company checklist and complete each item before moving on to the next. This ensures no steps are missed and the aircraft gets configured correctly for the next stage of the flight.

Some of the items to prepare are:

• FMS – Flight Management System – This includes the departure procedures, routing, altitudes, weights, fuel loads.
• Radios – Required frequencies for Ground, Tower, and Departure controllers
• Performance – Knowing the performance data for the given atmospheric conditions, weights, and runway length is very important
• Electrical System
• Hydraulic Systems
• Fuel Systems
• Pressurization Systems
• HVAC Systems
• Lighting Systems

Once all the systems have been configured, some of them will need to have some tests run on them.

Safety System Checks

There are certain systems that have to be checked before the flight to ensure they are working correctly. If they fail the preflight test they could render the aircraft ‘Out Of Service’

These systems are usually very important with redundancies built-in and testing them ensures they will be ready to do their job correctly. Some of the typical systems that get tested will either have a built-in automatic test function or will require the pilot to do a series of actions.

Some of the systems to be tested can include:

• Screens – Making sure no color pixels are missing – Important for limitation markings on the data fields
• Warning Lights – Ensuring no bulbs or LED elements are not working
• Fire Systems – Ensuring the sensors, wiring, firing, and retardant systems are ready
• GPS – Ensuring GPS coverage for all phases of flight
• Hydraulics – Testing the valves, pumps, and pressures are working

Just like the systems to be set up above, the number of systems to be tested will vary. As you can imagine, the number of systems on a Cessna 172 will be negligible compared to the systems on a Boeing 787 Dreamliner!

To Finish

Once all the aircraft, systems, pilots, cargo, and passengers are ready can the request to taxi be made. The bigger the aircraft, the more there is to check but in essence, the backbone of the things that need to be read, tested, and configured remains pretty much constant for every pilot.

Every pilot needs to know the aircraft, weather, airspace, and passengers are good before take off as those pilots that cut corners on pre-flight preparation are the ones you end up reading about when something goes wrong.

Pre-flight routines are one of the most important aspects of any flight and when done with diligence and routine they make flights so much safer!

Header Image:
Source: Kristoferb

Further Reading

If you found this article interesting and would like to keep reading, I highly recommend the following articles from my blog:

• Aircraft Checklists: Why Do Pilots Use Them?
• How Do Pilots Know When To Takeoff?
• Aviation Weather Information: How do Pilots Get It?
• How Do Aircraft Avoid Each Other?
• Finding the Right Runway: How Do Pilots Know Where To Land?

Have you ever watched a documentary and seen an Air Traffic Controller’s radar screen? It looks like complete chaos! Dots moving all over the place surrounded by numbers and arrows, how do they keep control of all that stuff?

Aircraft avoid each other by two means: First, by visual separation from the pilots, but when in cloud, at night, or up high, air traffic control give the pilots headings, altitudes, speeds & direction to maintain separation clearances from other aircraft using their radar & radio communications.

When I was first learning to fly I was intimidated talking to air traffic control so I spent a Sunday afternoon sitting next to both a tower controller and an approach controller and learned all about how aircraft avoid each other as well as overcoming my fear of talking to them!

The way pilots fly is split up into two ruling sections:

1. VFR – Visual Flight Rules
2. IFR – Instrument Flight Rules

Each of these types of flying has rules governing how aircraft avoid each other

Aircraft Avoidance Under VFR Flight

VFR Flight is by far the most common type of flying done outside of the airlines. When private owners, recreational fliers, and most helicopter operators go out flying they are having to maintain visual reference to the earth’s surface, hence Visual Flight Rules.

Basically, the pilots are out there doing as they wish once outside of or under the controlled airspace surrounding the larger airports and the airway system. It is up to the pilot to keep a watch for other aircraft using their own eyes and any technology like TCAS (Traffic Collision & Avoidance System) if they have it installed in their aircraft.

Referred to as the Mark 1 Eyeball, a pilot’s sight is the main avoidance device when flying VFR. When a pilot does encounter another aircraft there are several rules that help provide a safety margin:

• The lesser maneuverable aircraft has right of way (Balloon vs Plane, Glider vs Helicopter etc)
• The aircraft on the right has the right of way
• When approaching head-on, both aircraft turn to the right
• When overtaking a slower aircraft, overtake to the right side of the slower aircraft
• When flying over 3000 feet above the ground:
  • Aircraft being flown between headings of 0°-179° will fly at ODD thousands of feet + 500 = (3,500ft|5,500ft|7,500ft etc)
  • Aircraft being flown between headings 180°-359° will be fly at EVEN thousands of feet + 500 = (4,500ft|6,500ft|8,500ft etc)

When flying at night these rules also apply and even though it is dark all aircraft flown at night must have a mandatory lighting system installed and turned on. Aircraft lighting is arranged so pilots can determine the direction of flight of the other aircraft depending on the light colors they can see:

The last line of defense a pilot has when flying VFR is good radio calls, even if they think no one is there. Giving clear position reports at unmanned airports or common air-to-air frequencies will let other pilots know if they are in the same area together.

A good position report broadcast over the radio should contain the following:

1. Who you are
2. What frequency or frequencies you are monitoring
3. Where you are
4. What altitude you are at
5. Where you are heading
6. Any other pertinent information

For example, this was a VFR radio call I used just the other day:

“Red Lake Area Traffic on 122.8
Astar Foxtrot Oscar Romeo Sierra
Just off of Springpole Camp
2000 feet
Eastbound towards Red Lake
With an External Load“

It is surprising how many times I get up flying, give a position report of where I’ve just lifted from, and then 3-4 other pilots chirp up and inform everyone else of their position.

By doing this it helps a pilot build a mental picture of where everyone else is in relation to them – This is known as Situational Awareness.

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Aircraft Avoidance Under IFR Flight

IFR Flight is by far the most common type of flying done by the airline and corporate jet industry. It allows aircraft to fly in all weather and at night because the pilots fly the aircraft by sole reference to the instrumentation with guidance from air traffic control, hence InstrumentFlight Rules.

Because there is nothing to see out of the window when the aircraft is in the clouds, above the clouds, at night, or in poor visibility, the pilots have to look at the instruments (mainly on glass screens now) in front of them to see what the aircraft is doing. Think of this as driving your car from home to work just by looking at the GPS and the instrument dials.

When flying under IFR rules, air traffic controllers are responsible for keeping all aircraft separated from one another because the pilots cannot see anything out of the windows. They do this by assigning your aircraft a timeslot in that part of the sky and no other aircraft can be in it at the same time as you.

To maintain separation control they will issue commands to the pilots over the radio. These commands could include:

• Headings to fly
• Altitudes to climb or descend to
• Speeds to fly at
• Other radio frequencies to change over to
• What number an aircraft is in sequence for landing
• Helping the pilots deal with an emergency

This is like one of the trains you may see in a sushi restaurant that keeps driving past you with plates of food on each carriage. Two plates cannot be carried at the same time, but when the chef sees an empty slot, he drops a plate of food into there and that spot is now filled.

When an aircraft takes off under IFR flight rules it will be passed from one air traffic controller to another as it passes through the country/globe. An air traffic controller has a set area of the sky they look after and it is their job to get every aircraft through it safely without breaking any of the minimum aircraft separation laws that govern them.

The controller’s area of the sky might be small but busy, like the approach to a busy airport like Atlanta, or it could cover several US states because aircraft are en route and up high just transiting through. Each area is designed to keep the workload of all the aircraft within it at a manageable level for the air traffic controllers.

TCAS

As air traffic controllers are human, it is inevitable that mistakes have and do happen which has ultimately led to mid-air collisions, all of which are fatal. After multiple mid-air collisions in the US, the FAA pushed for a system to be designed that can be fitted to aircraft to warn pilots if it detects an aircraft within their vicinity.

The system that was developed is called TCAS – Traffic Collision & Avoidance System. It is now mandated that any US-registered aircraft with over 30 seats must have a TCAS system installed and most IFR-capable aircraft also have this fitted as it really is a great tool, even in VFR use too!

All IFR Aircraft are fitted with a device called a Transponder and this device sends out information about the aircraft when it is interrogated by an outside radio signal, like that of an air traffic control radar or a TCAS of another aircraft.

The TCAS in every aircraft is constantly sending out interrogation requests and when the transponder of another aircraft gets that request, it sends it the information.

This is like a lecturer calling out into a dark classroom “Is anyone in here?“. If there is a student, they say “Yes, I am here! I am standing at your 2 O’clock and I’m sitting on the ground below you” – This is just how TCAS works

When the TCAS on an aircraft receives information about the other aircraft it can display the position of the other aircraft on the glass screen in front of the pilot. When it detects that the other aircraft is within 1,200 feet of your altitude and within 6 nautical miles, it will display that aircraft as a diamond on the screen in the geographic area in relation to you.

The cool feature about TCAS is that it can also tell if the other aircraft poses a danger and shout out instructions to the pilots on what to do. If another aircraft gets much closer than those parameters, it will change to an amber circle and set off an audible alert to the pilots: “Traffic, traffic”.

Depending on the sophistication of the TCAS systems installed, it can communicate with the TCAS system in the other aircraft and coordinate collision prevention directions. In one aircraft it would tell the pilots to climb while simultaneously telling the pilots of the other aircraft to descend!

I have used this system and it works great, the only downfall is when you are flying IFR and someone in a private plane is flying up high and has no transponder turned on. Even though they are unaware they are in controlled airspace it can cause some tense moments when they just suddenly appear!

To Finish

Following set rules and procedures, instructions given by air traffic controllers, and avoidance systems like TCAS are all the primary ways many aircraft remain clear of one another.

But, no matter what a system or someone on the radio is telling a pilot, the view from the pilot’s eyes is always the last line of defense in preventing near misses or worse.

Keeping a vigil eye open for aircraft at all times, even when it is pitch black will help increase the safety margin on any flight. When pilots are out flying by themselves it is always good airmanship to give out position reports over the radio because there just might be another aircraft close by they have not seen!

Further Reading

If you found this article interesting and would like to keep reading, I highly recommend the following articles from my blog:

• How Do Pilots Know When To Takeoff?
• Before Taking Off – What Do Pilots Check?
• Aviation Weather Information: How do Pilots Get It?
• Can Pilots Turn On Runway Lights From Their Aircraft?
• Finding the Right Runway: How Do Pilots Know Where To Land?