iFly Blog

Capt Stephen

 

Many members of the general public share a common view of an airline pilot’s workday. This stereotype often involves a pair of pilots relaxing in the cockpit, sipping coffee, and occasionally monitoring the flight instruments while the autopilot does the rest. The average layperson might believe pilots enjoy this relaxing environment for 2-3 hours at a time before arriving at their destination. While this might be true in some instances, for many pilots such a description varies greatly from reality. For countless commuter pilots, the opportunity to relax in cruise is nothing more than a distant dream.

For many regional airline pilots, those who fly the “puddle jumper” routes, the cruise leg of a given flight is often not much longer than most other phases of flight. As regional airlines often operate to smaller cities surrounding their carrier’s hub, flight legs can be as short as 100 miles, sometimes even less. As a result, cruise legs sometimes last no longer than a few minutes. During this time, as well as all other phases of flight, pilots remain busy attending to a multitude of tasks. More often than not, these duties involve some form of paperwork.

Checklists

All pilots, regardless of experience level or the type of aircraft they operate, refer to checklists for EVERY phase of flight. Checklists begin with the pilots’ preflight inspection(s) and cover each segment of their operational duties until the aircraft is secured at its destination. For each phase, the pilots refer to the appropriate checklist and jointly verify that every requisite task has been completed. The shorter the flight, the more quickly the pilots must cover each checklist. The more legs a pilot flies in a given day, the more times (s)he’s required to run checklists. For many regional pilots, “flying” the plane is a continuous exercise in completing checklists.

Weight & Balance

All aircraft are certified to operate within specific weight and center of gravity (c.g.) parameters. For every flight leg, the pilots must determine that the plane is operated within the appropriate weight and balance limitations. This means calculating the effects of fuel, passenger weights, baggage & cargo, and the aircraft’s weight itself for EVERY single flight leg. In addition, weight limitations can be further restricted due to certain runway, atmospheric, and operational limitations. At times, pilots will need to offload weight or rearrange passengers/cargo in order to obtain a satisfactory weight/c.g. combination. For commuter pilots, math skills are a must.

Takeoff & Landing Distances

Like weight & balance, takeoff & landing distances must be calculated for every single takeoff and landing. These distances are affected by aircraft weight, temperature, atmospheric pressure, runway length, runway slope, and terrain/obstacles near the airport. With so many variables to consider, the same runway might be perfectly fine for one takeoff/landing but unsuitable for the next. Additionally, snow/ice/rain on the runway affect performance and must be carefully considered. In extreme instances, flight crews must delay takeoff and/or reduce aircraft weight in order to takeoff/land at a particular airport.

Speeds & Power Settings

Like other performance data, power settings and target airspeeds (commonly referred to as V-speeds) vary with weight and temperature/pressure. Though many modern aircraft computer systems can calculate several of these numbers, crews of older aircraft must manually determine the appropriate settings to use. In some instances, particularly on hot days and/or at high elevation airports, the aircraft engines can be incapable of producing the necessary speed/power required for takeoff. When this happens, pilots must reduce weight and/or wait for cooler temperatures in order to depart. Regardless of airplane type, all pilots must verify the speed & power requirements to determine whether a given flight is feasible.

For commuter pilots, every flight leg requires near-constant attention to numerous sources of paperwork. Besides the requisite data listed above, pilots must consult weather reports/forecasts, navigational charts, airport diagrams, and company manuals. On short flights, getting through the sheer volume of necessary documents can be a daunting task. In addition, pilots must fly their aircraft and ensure the safety of their passengers. For regional pilots, a day at the office can be anything but a carefree experience.

 

Continuing our Preparing to Launch series, we’ll take another look at the duties airline pilots perform prior to takeoff. When you board an airliner, you’ve probably glanced into the cockpit and noticed the pilots intently engaged in some activity. If you’ve wondered what exactly they’re doing up there, we’ll demystify the process by highlighting some of these tasks.

The preflight inspection consists of two major parts: the internal preflight and the external walkaround. While both are vitally important parts of the pilots’ preparation, we’ll concentrate on the internal portion for this post. Prior to pushback, airline crews must complete several steps to ensure the aircraft is safe and legal for the upcoming flight.

Aircraft/Maintenance & Flight Logs

After reading through the Flight Release (see previous post), pilots will refer to the Aircraft Log (sometimes referred to as the Maintenance Log) and the Flight Log. In the Aircraft Log, the crew is checking to ensure that all required inspections are up-to-date and properly documented. Additionally, they’ll verify that any inoperative equipment complies with the Minimum Equipment List (MEL; details in previous post) and is properly placarded. If everything appears satisfactory, the captain will sign the Aircraft Log to accept the aircraft. If anything requires attention, (s)he’ll coordinate with the airline’s maintenance department to address the issue(s).

The Flight Log maintains a record of the aircraft’s utilization. In this document, the flight crewmembers record their names & positions, as well as the duration of all legs they fly. This log also keeps track of aircraft & engine cycles (number of engine starts and number of landings). On many modern aircraft, some of this information might be entered and stored electronically. As with the Aircraft Log, the captain will sign the Flight Log when accepting the aircraft.

Panel Scans and Checklists

If you’ve noticed pilots actively pushing buttons, flipping switches, and moving levers as you’ve boarded an airplane, you’ve seen them running their panel scans and checklists. Before each leg, both pilots complete a checklist to verify the position and operation of the plane’s systems. Each pilot has his own cockpit flow, a type of memorized checking procedure, he performs to review the systems he’s responsible for. For the first flight of the day and/or each crew’s first leg in a particular aircraft, the panel scans are especially thorough. For subsequent legs, certain items may be abbreviated.

When these scans/flows are complete, the crew will refer to a checklist to verify they’ve covered all necessary items. Any faulty equipment will be rechecked for proper operation. If maintenance is required, the crew will notify company mechanics. Occasionally, the flight will be delayed or a new plane will be assigned. For minor issues, it’s often possible to MEL the item and continue the flight.

Weather and Clearance

Shortly before pushback, the crew will obtain the departure airport’s latest weather observation. This info may be manually recorded or generated automatically, depending on the airport’s weather reporting system. Pilots use this data to supplement/update the weather information in the Flight Release and to verify the legality & performance parameters of the upcoming takeoff. When they contact Air Traffic Control (ATC) for taxi instructions, they’ll let the controller know they have the latest weather info by stating the phonetic identification (Alpha, Bravo, etc.) of the most recent broadcast.

After obtaining the latest weather report, crews will contact ATC to receive their clearance. The clearance is a game plan for the flight leg. It includes the initial altitude to climb to after takeoff, the subsequent altitude to expect, the route of flight/heading to fly, the radio frequency to use after takeoff, the transponder identification code, and any other pertinent information. The clearance is obtained before pushback to allow the crew to set up their radios and navigational equipment prior to departure. Doing so minimizes workload during taxi and takeoff, which helps enhance safety.

As you can see, airline pilots have a significant workload to prepare their aircraft for each flight. In a future post, we’ll examine additional crew responsibilities and how each contributes to the safety and comfort of the flight. We’ll also cover the external aircraft preflight. Stay tuned!

 

With this post, we’ll begin looking at the duties and responsibilities commercial airline crews undertake prior to beginning each flight. As you’ve probably guessed, airline personnel are responsible for numerous tasks before a given flight can actually leave the gate. One of the first steps airline pilots take is to look over the flight’s paperwork. The main document airline crews consider is known as the Flight Release.

The Flight Release, also known as the Dispatch Release or simply, “The Release,” is the master plan or blueprint for the entire flight leg. This document is prepared by the airline’s dispatch department and transmitted to the crew at their departure airport. The release contains vital information on the route, weather, fuel requirements, maintenance/equipment, and any other information pertinent to the flight. The Pilot in Command (the Captain) must determine if, based on the info in the release, the proposed flight can be completed both legally and safely. If everything appears satisfactory, the captain signs both copies of the release and leaves the station copy with gate personnel at the departure airport. The crew retains the other copy for use during the flight.

Flight Plan

A major part of the release is the flight plan section. This portion outlines the proposed route of flight, cruise altitude, alternate airport(s) (if necessary/requested), weather reports & forecasts, temporary flight restrictions (if applicable), pertinent Notices to Airmen (NOTAMs), and any other relevant data. From this information, the crew is alerted to possible adverse weather, probable air traffic control (ATC) routings, estimated trip duration, and other reasonably foreseeable information. Though helpful for planning, routing and altitude are ALWAYS subject to change, particularly in busy airspace and during bad weather. In such instances, the crew can expect to receive ATC instructions, while they may also request preferred routing/altitudes.

Fuel Requirements

The fuel section is an extremely important part of the release. This section lets the crew know how much fuel they need in order to legally depart. This specified minimum includes fuel for engine start, taxi, takeoff/climb, cruise, descent, landing, and taxi to the gate. If alternate airports are required, the necessary fuel to fly those routes is included. In addition, all flights are required to carry additional fuel (usually at least 45 minutes’ worth) as a cushion for possible delays. At times, flights may choose to depart with more fuel than is legally required. However, such practices aren’t common, as airlines prefer the increased performance & payload capacity afforded by carrying only the necessary fuel.

If the captain notes that the aircraft is underfueled, (s)he must request & receive enough additional fuel to arrive at the legal minimum. In addition, if the pilots determine that (despite having the legally required amount) they would prefer extra fuel, they will coordinate with dispatch and ground operations to acquire the amount deemed necessary. In all instances, the captain has the final authority for the flight’s operation.

Equipment (Inoperative/Restrictions on Use/ MELs)

Due to the vast amount of equipment carried aboard commercial aircraft, it’s extremely common to have certain items inoperative on any given flight. For such instances, the airline has a Federal Aviation Administration (FAA) approved list, called a Minimum Equipment List (MEL), which specifies items that may be inoperative under certain conditions. Any inoperative equipment will be listed on the flight release. The pilots must then refer to the aircraft’s MEL, determine possible effects of the inoperative equipment, establish how long the equipment has been inoperative, note how long the equipment may legally remain inoperative, and verify that any necessary placards/maintenance forms have been properly completed. If any inoperative equipment threatens the safety/legality of the flight, the crew must request maintenance be performed or a new aircraft be provided before beginning the flight. In some instances, the flight will be delayed or canceled while maintenance is performed.

Airline pilots are responsible for overseeing every aspect of the flights they operate. The flight release is the main document that facilitates coordination of all requisite tasks. Through the release, the pilots can assess the demands of the upcoming flight and take all necessary measures to ensure the safety of their passengers.

 

 

Last time, we highlighted many of the cockpit tasks airline pilots perform prior to each departure. In this post, we’ll head outside the airplane to examine the external aircraft walkaround. This preflight procedure is equally important to all pre-takeoff cockpit checks and is a mandatory part of each flight leg. Through the walkaround, pilots are able to further enhance the safety and comfort of their passengers.

Why the Walkaround?

Throughout the aviation industry, safety is the paramount concern. Much of the airline industry’s stellar safety record is achieved through minimizing/eliminating foreseeable risks. The external aircraft preflight is a highly effective method of risk minimization. Unlike with ground-bound modes of transport, aviators can’t just pull over to the side of the road in the event a mechanical issue arises. For this reason, a detailed examination of the aircraft’s structure and systems is necessary to reduce the chances of an in-flight malfunction.

Tires and Landing Gear

Though used for only a fraction of each flight, the landing gear system is a vitally important safety component. Think about it: airliners are multi-ton monoliths larger than most houses. Additionally, even at their relatively slow approach speeds, they’re still travelling faster than anyone outside of the NASCAR circuit ever drives. The stress of several landings a day means the landing gear and tires have to be ridiculously tough to handle those weights and speeds. A malfunction here could make for a very memorable landing.

On the walkaround, pilots observe such factors as the tread, inflation, and wear of the tires. They’ll also examine gear struts, hydraulic lines, brake components, nuts/bolts/fasteners, and anything else noteworthy for their model. Anything appearing out of the ordinary will be addressed before the crew will consider departure.

Engines

As you’ve probably guessed, the powerplant is the heart of the plane. Without fully functioning engines, a state-of-the-art airliner becomes a very expensive glider. To avoid this undesirable possibility; pilots look for leaks, signs of scorching, evidence of foreign object damage (FOD), worn/overstressed components, and anything else that appears irregular. In some cases, maintenance personnel assist with the inspection, due in part to the engines’ often-unreachable height. These external inspections are then cross-referenced with cockpit indications to ensure full engine functionality. In case you’re wondering; all commercial aircraft are rigorously tested and certified capable of taking off, flying, and landing with an inoperable engine. Should an unlikely engine failure occur, the other engine(s) are capable of sustaining flight.

 

Lights

Despite their massive size, at times airliners can be difficult to see; especially under low visibility conditions and at night. In these instances, external lights go a long way towards helping the aircraft show up. Navigation lights and anti-collision lights are among the most common lights used to make the aircraft stand out. On the walkaround, pilots check to ensure these required lights are operational.

Additionally, at night and during low visibility conditions, external lights greatly assist the pilots in seeing the airport environment. Landing lights and taxi lights are the most common lights that aid in seeing outside the aircraft. For winter weather, some planes have ice lights, which assist the crew in detecting ice accumulation on the wings. Pilots verify proper operation of these external lights when conducting the exterior preflight.

Airframe

Throughout the walkaround, the pilots inspect the various sections of the airframe. From nose to tail, they look at the fuselage, wings, and empennage for any indication of damage or defects. Depending on the airplane model, other items that might be scrutinized include: flaps, spoilers, ailerons, static wicks, static ports, pitot tubes, antennas, radar pods, pneumatic deice boots, and countless other model-specific parts. Any components appearing suspect are further evaluated to ensure safe operation.

The demanding environment in which airliners operate requires all systems to perform flawlessly. An external preflight inspection helps pilots detect possible deficiencies and minimize the chance of malfunctions aloft. Through their preflight walkarounds, pilots are able to reduce risk and enhance the safety of their passengers.

 

            In the previous few posts, we discussed the internal and external preflight inspections airline pilots conduct prior to departure. In addition to those important tasks, pilots must coordinate with a variety of support crews to ensure the aircraft is ready for pushback. While these support teams are largely capable of completing their respective tasks independently, the captain is ultimately responsible for assuring that each team’s operations are conducted safely and legally.

Flight Attendants

For airline passengers, the cabin crewmembers are the most visible support staff. Flight attendants (FAs) are responsible for taking care of nearly all passenger needs. In addition to serving snacks and beverages, FAs supervise passenger safety. In this role, they conduct a thorough safety briefing, confirm that all passengers are wearing safety belts, make sure carryon luggage is properly stowed, and attend to special needs passengers. Additionally, cabin crewmembers conduct the passenger count and make sure it matches the flight’s manifest. At some airlines, FAs assist with weight & balance calculations. As a passenger, the cabin crewmembers will be your point of contact once you’ve boarded the aircraft.

Gate Agents

Think of gate agents as the pre-boarding flight attendants. They’ll be your point of contact for all matters prior to boarding and after deplaning. In their role, gate personnel oversee the boarding process and ensure only ticketed passengers enter the plane. They confer with the pilots & FAs to verify their passenger count matches the number of travelers aboard. Gate agents also make arrangements for special needs passengers (arranging for wheelchairs, interpreters, etc.) and chaperone unaccompanied minors (UMs). Should you miss a connection or lose your luggage, the gate personnel are the people who will sort out the mess. In their role, gate agents greatly assist the crew by streamlining the boarding process to the furthest extent possible.

Baggage Handlers

Baggage handlers do more than just load your luggage. They assist the pilots in keeping the plane within its weight & balance limits. Rather than just blindly tossing bags into the cargo hold, baggage handlers maintain a precise record of exactly what goes into each cargo bay. This includes regular size bags, oversize luggage, and sometimes hazardous materials (HAZMAT). They ensure that everything loaded into the plane is properly secured and may legally be carried. At times, it’s necessary to rearrange or offload cargo to remain within weight & balance limits. While the pilots ultimately determine what must be done, the baggage crew carries out the request to load the aircraft within the proper parameters.

 

Ground Crew

Ground personnel carry out the fueling of the airplane. After the pilots & dispatchers determine the requisite fuel load, the ground crew uploads the proper amount of fuel to the aircraft. During winter, they also apply deicing fluid to remove ice & snow from the plane. Additionally, the ground crew loads water, food, and beverages onto the aircraft. When it’s time for pushback, they operate the tug that moves the plane away from the gate and maintain proper clearance from obstacles around the plane. Upon arrival at the destination, ground personnel guide the plane into the gate. For both departure and arrival, the ground crew are the people who connect the plane with the terminal.

Company Operations

Company Ops are the people on the other end of the microphone. In addition to recording the arrival & departure times, they coordinate their airline’s flights with all ground support teams. When the pilots request fuel, deicing, maintenance, baggage, or assistance with passenger needs, Ops personnel pass the request along to the appropriate team. They also keep the crew apprised of any delays or updates relevant to the flight. Of all the ground-based crews, Ops is the team that brings everything together.

As you can see, each airline flight requires a significant amount of planning and input before it’s ready to leave the gate. While the captain is ultimately responsible for the safety and legality of the entire operation, the various support teams play an integral part in preparing the flight for departure. The next time you have a hassle-free airline experience, remember the part the supporting crews play in its outcome.

 

In our last look at turbulence, we discussed the various forms of low-level turbulence; bumpiness found below approximately 15,000 ft. With this post, we’ll cover causes of high-altitude roughness. As an airline passenger, most of your travel time will be spent in high-altitude cruise. Turbulence encountered during this stage of flight will likely last longer than most low-level turbulence experienced after takeoff and on the landing approach. We’ll also discuss turbulence common in mountainous areas. Once you’re familiar with the characteristics of these forms of turbulence, you’ll be better able to understand when, where, and how long such turbulence is likely to last.

Clear Air Turbulence (CAT)

While clear air turbulence can occur at any altitude, it is most common above 15,000 ft. CAT is the result of airflow from different directions and/or of differing speeds converging. At higher altitudes, CAT is often found in or near the jet stream. Depending on the route & altitude of flight, CAT can persist for hundreds of miles.

Detecting it:  Probable areas of clear air turbulence can often be determined before the flight takes off. Pilots and dispatchers refer to winds & temperatures aloft forecasts and reports to determine wind speed & direction at various altitudes. If wind direction and speed change significantly over small changes in altitude, that’s a sure sign of possible turbulence. The greater the variation, the stronger likelihood of turbulence.

Additionally, airline crews examine Pilot Reports (PIREPS) filed by other pilots. PIREPS are possibly the most valuable resource for locating turbulence, as other planes are reporting the exact location, altitude, and intensity of roughness aloft. With weather forecasts, the best pilots can do is guesstimate where/when/how strong turbulence might be found. PIREPS are available via aviation weather sources, or they can be relayed directly to airliners by air traffic controllers (ATC).

Avoiding CAT:  As you might imagine, no one wants to fly through turbulence if it’s avoidable. Pilots and dispatchers consider weather reports/forecasts and PIREPS when determining the route & altitude for flight. In some cases, changing altitude or varying the route will avoid the most turbulent areas.  At other times, CAT is so pervasive that the only option is to ride out the bumps.

Mountain Wave Turbulence

As the name implies, mountain wave turbulence is found near mountainous terrain. This form of turbulence results from air being disrupted as it flows over (perpendicular to) mountains. Think of it as mechanical turbulence (see previous post) on steroids. The disrupting peaks cause the air to undulate on the downwind side of the range(s). With strong winds, these oscillations can persist for over 100 miles and cause severe turbulence.

Detecting it:  For flights traversing mountainous areas, pilots and dispatchers will look at wind reports and forecasts for the upwind side of the range(s). Speeds above 40 knots are most conducive to mountain waves. Below 25 knots, this possibility diminishes. With widespread light & variable winds, mountain wave turbulence is a nonissue.

In addition, mountain wave turbulence can often be located by noting unique cloud formations. Rotor clouds and lenticular clouds (Google them for some great images) can form below and above the wave crests respectively when sufficient moisture is present. Cap clouds, which form above mountain peaks, can also signify mountain waves.

Avoiding Mountain Waves:  If you fly over flatlands, mountain wave turbulence is a nonissue. For flights near high terrain, staying at least 3,000-5,000 ft. above the peaks is generally effective to overfly any hazards. Most commercial flights will be well above these altitudes. For takeoffs & landings at mountainous airports, crews monitor weather reports/forecasts, PIREPS, and ATC updates. They also plan climbs & descents to avoid the most hazardous areas. In extreme cases, they’ll delay/cancel the flight in the interest of safety.

When it comes to turbulence, airline crews go to great lengths to avoid or minimize bumpiness for their passengers. If safety is an issue, pilots have no trouble postponing the flight to await favorable conditions. As an airline passenger, any turbulence you experience is likely unavoidable and not considered hazardous. Though annoying, consider in-flight turbulence a small price to pay to arrive safely at your destination.

 

For most air travelers, turbulence is a word that invokes at least a little dread and discomfort. However, in most cases such apprehension is at least partly due to fear of the unknown. Once we better understand the subject, our newfound knowledge can help allay unnecessary anxiety. With this series of posts, we’ll examine the causes of turbulence and methods for avoiding and mitigating any encounters.

In this post, we’ll examine the types of low-level turbulence. Low-level turbulence includes all forms of turbulence found below an altitude of approximately 15,000 ft. Regardless of your flight’s eventual cruise altitude, all aircraft must pass through these lower levels after departure and prior to arrival at the destination airport. At times, certain low-level turbulence is unavoidable and is best handled when properly understood.

Mechanical Turbulence

Roughly defined, turbulence is an irregular motion of the atmosphere. Mechanical turbulence is caused by terrain, buildings, or other structures disrupting the smooth airflow through a given area. This type of turbulence is most commonly encountered during takeoff and landing when hills, ridges, or infrastructure around the airport interfere with the flow of surface winds. Based on their surroundings, some airports are more susceptible to mechanical turbulence than others. When encountered, mechanical turbulence only lasts for a few minutes and will dissipate after landing or once climbing a few thousand feet upon takeoff.

Convective Turbulence

Commonly referred to as thermals, convective turbulence is generally associated with warm weather. This turbulence is caused by solar heating reflecting upwards off the surface. The higher the temperature, the stronger and higher you can expect the thermals to be. When sufficient atmospheric moisture is present, cumulus clouds tend to denote the upper extent of thermals. As with mechanical turbulence, convective turbulence is limited to within a few thousand feet of the surface and will only be experienced during takeoff and landing.

Frontal Turbulence

As the name implies, frontal turbulence is typically found ahead of a fast-moving cold front. You can anticipate frontal turbulence by watching the weather before your planned departure. If a cold front is approaching your departure or destination airport, you might encounter some frontal turbulence. En route, such encounters are generally not an issue, as frontal turbulence is most common at lower altitudes. However, if you’ll be cruising at low altitude (on commuter aircraft or short legs), it’s possible you’ll encounter this turbulence in cruise. In such cases, the pilots, dispatchers, and air traffic controllers (ATC) can often coordinate to avoid the most probable turbulence areas.

 

Wake Turbulence

Though categorized as a form of turbulence, wake turbulence is generated by aircraft, not the atmosphere. While all aircraft generate some turbulence as a result of lift, the strongest wake turbulence is produced by heavy aircraft during takeoff and landing. To combat wake turbulence, ATC maintains minimum separation distances between aircraft. On the ground, aircraft are sometimes required to hold for a few minutes to allow wake turbulence to dissipate. Additionally, pilots can request additional separation/hold time if they judge it’s in the interest of safety. Due to the wake turbulence avoidance procedures used by pilots and ATC, your chances of encountering wake turbulence are extremely rare.

What can you do?

As a passenger, your best defense against low-level turbulence is knowledge of its characteristics. By referring to the information above or researching the topic on your own, you’ll be better prepared for possible low-level turbulence encounters. In many cases, your knowledge of when, where, and how long turbulence is likely can go a long way to relieving any anxiety about an encounter. During flight, try to remain seated with your seatbelt fastened. Secure your personal items to the extent possible and keep a hand on any foods and drinks, particularly hot items. If a trip to the restroom is necessary, try to go before entering or after exiting expected turbulence zones.

In a future post, we’ll discuss other forms of turbulence and identification/planning/avoidance methods used by pilots and ATC. Don’t let a chance encounter with turbulence keep you from enjoying your time aloft. The more you understand its causes, the better you’ll enjoy your flight.