[Ref The turbine pilot’s flight manual Review (ISBN:9781619540293)]
Pilots should know well about their plane, including different limitations, which are set to ensure the plane work under safe and efficient conditions. However, this chapter also aims to point out those special or dedicate to turbine aircraft
- there is no redline on speed indicator of turbine aircraft
- Use “maximum operating limit speed” (e.g Vmo,Mmo) rather than “Never exceed speed, Vne” in piston engine
- Vmo is a structural limit designed to prevent airframe damage from excess dynamic pressure.
- Mmo is a limit designed to prevent aircraft from shock wave damage as the aircraft approaches the speed of sound.
- Vmo and Mmo are not fixed and they are vary with altitude
- Generally speaking, at lower altitudes, Vmo is the “maximum operating limit speed” (so Mmo is the “maximum operating limit speed” at higher altitudes)
- Turbulent air penetration speed (Vb), is a limit on turbine engine, which offers maximum-value gust protection (Maneuvering speed, Va, is still existing like piston engine)
- Landing gear extended speed (Vle), is the speed limit at which it is safe to fly with the landing gear secured in fully extended position
- Landing gear operating speed (Vlo), is the speed limit at which it is safe to extend or retract the landing gear
- Engine limits
- EGT (exhaust gas temperature) or ITT (interstage turbine temperature) are two limits on turbine engine, not piston engine
- “hot start” is indicated when EGT or ITT shoots past normal start-up values and heads toward redline
- As a pilot, we definitely have to show “TCL” to the engine(s) as it is the power source and it is valuable!
- Other system limitations
- Anti-icing system
- Fuel system
- Hydraulic system
- Oxygen and fire extinguisher systems
- Speed-brake – e.g prohibited with landing flaps extended
- fuel tank (imbalance) – related to the CGu
- Maximum operating altitude
- Auxiliary Power Unit (APU) – most APU have maximum altitude operating limitations
- Operational limitations
- minimum flight crew (cockpit and cabin) – to comply the regulation
- pilot paring – prevent an inexperienced captain and a brand-new F/O combination
- Age limitation – e.g over age 60
The chapter 8 gives us a very important concept in business and commercial operations of turbine aircraft – multi-crew cockpit.
Minimum two-member crews are not only for the purpose of complying regulations, it is the requirements of insurance and company policies.
Captain is in command at all times and “owns” the responsibility for all aspects of a flight.
The copilot (First officer), is basically a professional assistant to the Captain and under his or her command.
However, in most operations, the Captain and FO alternate flight legs in order to have chances to keep sharp in various duties, and maintain variety. As a result, we use flying pilot (PF) and nonflying pilot/ pilot monitoring (PM) to distinguish who is flying.
PF, at all times, is to fly and maintain safe control of the plane while the PM is to perform all other duties that must be accomplished – including but not limited to reading and performing checklist items, operating radios, obtaining weather and flight information, calling out critical flight information (altitudes and fixes) etc.
Crew Resource Management (CRM) is another important concept brought out in the chapter 8.
I quite one of the paragraph:
Ideally, both pilots should evaluate choices before making them final, if time permits. In any case, the relevant saying goes, “Focus on what’s right, not who’s right!”
Checklists and Callouts are broadly discussed in the chapter 8 as well.
The primary function of checklists is to ensure that the flight crew safely and properly configures the aircraft before and during each flight.
Three (3) interrelated methods of conducting checklists are commonly used in turbine aircraft [Multi Crew Co-operation (MCC) cockpit]:
- flow checks
- do lists
Flow check is a checklist method where each pilot memorizes a sequential pattern for doing specific cockpit tasks.
Typically, the captain calls for the check – e.g “after start flows”. Each pilot starts at a specific panel location and works through every switch and indicator to confirm settings for various phases of flight. Some flow checks are then backed up with one of the following checklist methods (e.g Challenge-Response checklists) to ensure the completion of critical items.
Challenge-Response checklists are often used to follow up flow checks. It is literally as a double-checking method.
In general, it is called by PF. The PM “challenges” the PF by reading the items off the checklist to ensure completion; The PF then verifies that each item was accomplished properly by checking that item and then calling out the appropriate “response”.
Do lists are just what they sound like. Do lists are commonly used for cleanup or housekeeping chores. Be noticed that some do lists are silent.
The PM reads and accomplishes everything “on the list” for a given phase of flight.
After we know the methods of performing checklists, let’s take a look on the difference between mechanical (paper) or electromechanical checklists.
Mechanical (paper) v.s Electromechanical checklists:
Paper and mechanical checklists simply list tasks on a paper card.
Electromechanical checklists are also known as electronic and computer-aided checklists, which are developed by using EFIS (electronic flight instrumentation systems) or similar displays.
Speaking of checklist, it can be categorized by normal, abnormal and emergency checklists.
Normal checklists are used for routine in a flight. In general, there could be more than 10 checklists:
- before start
- after start
- delayed start/after start
- taxi checklist
- before takeoff
- cleared-for-takeoff /runway
- after takeoff
- initial/ approach
- final/ before landing
- after landing
- remain-overnight (RON)
Standard callouts are part of the routine made by multipilot crews.
Function of callouts includes:
- ensure that important tasks are remembered during critical phases of flight
- minimize the possibility of errors or problems going unnoticed
p.s please refer to the book for examples.
Emergencies occur relatively rare, so pilots are trained to stay sharp on procedures not often used. Indeed, proper emergency training develops the confidence and clarity of thinking required to deal promptly and effectively with a problem, without making it worse.
Emergency is a situation where immediate crew action is required in order to maintain the safety of the flight.
Rightly, any situation that merits a red warning light on the annunciator panel should be treated as an emergency until confirmed otherwise by the crew.
Some situations happen suddenly and may be so time critical that there is no time to look for the checklists until key momory items are completed. However, some have suggested that it is not really harmful to let a few seconds pass – to get the chcklist out first and to ensure that nothing is forgotten.
Don’t undermine emergency procedures, of which failure to immediately and properly exercise could jeopardize the plane and lives on board.
Actually, memory items must be learned to the degree of being second nature by every pilot.
Abnormal situations exist when something goes wrong that needs attention, but not with such immediacy.
Be noticed that abnormal situation can rapidly develop into an emergency if it’s not dealt with promptly.
The chapter 10 is about performance in turbine aircraft.
In turbine-power aircraft, with greater power engine(s) installed, most of them tend to operate much closer to their limits than typical piston aircraft – turbine aircraft are designed to operate routinely at high weights (full passenger or freight loads) and high altitudes or mountainous areas. As a result, this calls for more careful planning, especially for the possibilities of engine failures, go-arounds, and aborted takeoffs. Meanwhile, cruise speed and fuel planning have more significance in turbine aircraft’s operations.
Takeoff, climb, landing, and Engine-out performance
V1, Vr and V2 are among the turbine takeoff “V-speeds” familiar to turbine pilot.
These “V-speeds” allow the aircraft to achieve optimum or required performance for each particular phased/segment in the event of engine failure.
Significance of V1
V1 = takeoff decision speed =”go or no-go” speed
If an abnormality occurs before V1 is reached, takeoff is to be immediately aborted;
After V1, takeoff is continued, and the problem is then treated in flight.
Next, some may ask how to calculate the V1 speed. Rightly, a so-called “balanced field length“(BFL) V1 is determined during flight testing.
Most airline and corporate flight departments have historically based V1 speeds upon “balanced field length“(BFL) for their particular aircraft – if an engine failure occurs exactly at V1, the distance required to abort the takeoff and stop is the same as the distance required to continue the takeoff.(In familiar multi-engine terms, this means that accelerate-go distance equals accelerate-stop distance.)
However, more and more airlines adjust V1 to a lower speed than the BFL V1.
V1 cut is a term referring to the act, during pilot training or testing, of simulating an engine failure precisely at V1 on the takeoff roll.
Significance of Vr
Vr =takeoff rotation speed
Vr ensures the aircraft in the event of an engine failure, rotation at Vr to a specified pitch attitude will attain V2 by the end of the runway (with 35 feet above the surface)
Significance of V2
V2 =minimum takeoff safety speed
V2 allows the aircraft in the event of an engine failure, to maintain regulator (e.g FAA) required climb gradient in the climbout flight path.
Be noticed that terrain is considered in V2.
Vref is a typical turbine landing “V-speeds” familiar to turbine pilot.
Vref = landing reference speed
Be noticed that there is no single final approach speed used in large turbine aircraft – Vref accordingly increases with aircraft weight.
Weight ↑ , Vref ↑
Rule of thumb for calculating final approach speed:
Vref = 1.3 x Vs0
That is, 1.3 times the stall speed in landing configuration.
Here, we need to emphasis again that pilots should prepare for the worse. Therefore, V2 and climb gradient must also be considered in approach and landing phase – prepare for the need to execute go around or miss approach.
Routine performance planning
Aircraft are usually delivered to corporate or airline with manufacturers’ performance charts. However, these charts tend to be very complex and too time-consuming for flight crews to use routinely. Therefore, most flight departments develop quick reference performance charts for their flight crews.
Takeoff and Landing Data cards (TOLD cards), is a kind of quick reference material, which allow flight crews to quickly determine aircraft V1, Vr, V2 and Vref, along with power settings and other flight parameters.
Airport Analysis Table
“Airport Analysis” is a customized book of tables covering every authorized runway at every airport. It is a quick source of required aircraft performance under current conditions on any given day.
Be noticed that it is often impractical for a flight department to include an analysis for every runway and every intersection, so be careful when considering intersection departures!
Temperature-Derived Reduced Thrust Takeoff
Reduced thrust takeoff procedures, also known as assumed temperature thrust, flex-temp thrust, factored takeoff thrust and reduced thrust, are used to reduce engine wear and engine noise. The flight crew or the company’s performance engineering staff calculate a lower-than-maximum thrust setting that although requiring more runway, will still safely maintain regulator required minimum takeoff and climb performance.
Apart from outside air temperature (OAT) as a key factor, different factors are taken into consideration of reduced thrust takeoff procedures:
- contamination (e.g snow,ice, slush or standing water)
- anti-skid brakes ability
- weather conditions (e.g frontal thunderstorm activity)
Reduced thrust takeoff procedures ≠ Derated thrust
Derated thrust is a fixed value of thrust reduction without entering temperature (OAT) into the performance equations.
The derated engine may appear identical to the naked eye, but may produce significantly different amounts of thrust for various phases of flight. And the reasons of choosing derated engine include reduce engine wear and maintenance costs. Yet, it is a bit different from derated thrust since it would only be accomplished by a manufacturer or maintenance personnel on the ground.
The chapter 11 suggested some important terms of “weight and balance” topic.
Actually, weight and balance is an interesting topic for turbine aircraft pilots as well as all pilots.
Below are some terms particular important:
Maximum Zero-fuel weight (MZFW) – is maximum allowable aircraft weight excluding fuel. This is actually a structural limit.
With cabin load and not much fuel in wings’ fuel tanks, the wings can be over-stressed. The MZFW is preventing this situation.
Speaking of weight, this chapter gives us briefly concept on “Aircraft Weight Categories“, which classifies aircraft based upon its MTOW.
Small – MTOW 41,000 pounds or less
Large – MTOW more than 41,000 pounds, but not including 300,000 pounds
Heavy – MTOW 300,000 pounds or more
Super – A380
In the chapter 12, the writer tries to list out various positions with different roles in operations.
In US, flight dispatcher is a licensed professional, who do flight planning for an airline, including planning for weather conditions, fuel, cargo, and passenger loads. The dispatch flight release, which includes all information relevant to a given flight, is a kind of official document for a trip.
The captain reviews the dispatch flight release for the required amount of fuel and then ensures that the aircraft has been properly fueled.
In the chapter 12, the writer also gives us the concept of performing standard preflight.
A standard preflight may be broken down into 4 basic categories
- review of aircraft documents
- cockpit check
- emergency equipment check
- external check of aircraft
Blow are the documents that generally involved:
- Airworthiness Cert
- Aircraft Registration Cert
- Radio station License
- Aircraft Flight Manual
- Aircraft Maintenance and Flight Records
- Checklists (Normal, Abnormal, Emergency)
- Minimum Equipment List (MEL)/ Configuration Deviation List (CDL)
- Airport Analysis/ Aircraft Performance Data
- Takeoff and Landing Data Card (TOLD card)
- Load manifest
- Compass Deviation Cards
It is particular important to check if there is any “open write-ups” or unresolved maintenance issues.
The cockpit check is a flow check to ensure that switches, controls, and circuit breakers are in their proper positions.
Then, an emergency equipment check covers the presence and oprability of all fire extinguishing equipment, supplemental oxygen equipment, and emergency exists.
External check of aircraft (Exterior preflight check) of a turbine aircraft is similar to that on piston aircraft.
After finishing all routine mentioned above, the captain briefs the crew on the upcoming flight.
Be noticed that both MEL and CDL must be referenced prior to flight for any performance penalties, limitations, or procedures to be applied for operation.
MEL (Minimum Equipment List) contains items that are allowed to be inoperative on a given aircraft, while it is still considered airworthy – the MEL states what flight conditions, performance limitations, crew operating procedures, maintenance procedures, placards, and duration limits are necessary in order to be legal for flight with that component inoperative.
Remember that all equipment not listed in the MEL and related to the aircraft’s airworthiness must be operative – in other words, the aircraft may not be operated if any OTS (Out-of-Service) components are not specifically listed in the MEL or if any MEL items are out of date.
CDL (Configuration Deviation List) contains additional items and limitations for operation without secondary airframe or engine parts, while still allowing the aircraft to be considered airworthy – the aircraft could be considered “safe” and be operated even though certain equipment is inoperative, damaged, or missing (e.g missing panels, access doors and aerodynamic fairings).
The chapter 13 introduces lots of acronyms related to different navigation, communication, and electronic flight control systems.
Horizontal Situation Indicator (HSI) = Heading Indicator (HI) + Course Deviation Indicator (CDI)
Horizontal Situation Indicator (HSI) simply combines a Heading Indicator (HI) and a Course Deviation Indicator (CDI)
Sorces of CDI navigation information :
- ILS transmitter
- Inertial Navigation System (INS)
- Global Positioning System (GPS)
- Area Navigation (RNAV) computer
Autopilots are devices that automatically operate flight controls to fly the airplane. These autopilots can control single as well as three axes: pitch, roll and yaw to achieve various functions:
- maintain altitude
- hold a selected heading
- track navigational courses from VOR or other NAV equipment, and
- capture and shoot an ILS approach
Be noticed that autopilots ≠ auto-throttle!
Indeed, autopilots are extremely capable, but the crew must continual monitoring. Many accidents have occurred over the yeas due to unnoticed autopilot malfunctions or to poor programming and pilot inattention.
Flight Director provides information directly (through use of one or more “command bars” superimposed over the attitude indicator) to the pilots for use in precise hand-flying, but it does not have the ability to control the aircraft in any manner. There is flight director computer behind to process heading, attitude, and navigation information and determines what pitch or steering commands are needed to fly the aircraft correctly.
Electronic Flight Instrumentation Systems (EFIS) replace conventional electromechanical (analog) instruments with newer CRTs (cathode-ray tubes) or with flat panel displays – EFIS adopt using CRTs (cathode-ray tubes) or with flat panel displays (e.g LED).
Primary flight display (PFD), is the most standard of EFIS instruments, incorporates the traditional functions of the “Basic T“.
Multifunction display (MFD) or Nav Display presents some combination of navigation, radar, TCAS (traffic alert and collision avoidance system), and other flight information.
ACARS (Aircraft Communications Addressing and Reporting System) is an onboard computerized communications system that provides a digital, vioceless radio “data link” between an aircraft and its company operations center. Also, ACARS is typically linked to the aircraft’s flight management computer (FMC), allowing direct uploads of flight plans.
The messages are displayed as text on a cockpit screen while a built-in cockpit printer allows crew to generate hard copies of information. In general, the crews obtain weather, flight routings, loads, and various information through the system.
SELCAL is a selective-calling VHF or HF radio-monitoring system for alerting crew when a ground radio station is trying to communicate with the aircraft.
Each SELCAL-equipped aircraft is assigned a unique four-digit SELCAL code address. When someone needs to reach a particular flight, they simply dial the SELCAL code and the target SELCAL systems illuminate a light and sound an aural chime to signify an incoming call.
There are two major benefits of SELCAL communication for crews:
- need not maintain a “listening company watch”, and
- can get notification of incoming communications even when their radios have been muted
Head-up display (HUD) is a head-up guidance system (HGS), which incorporates a special transparent plate mounted directly in the pilot’s field of vision. This allows the pilot to shoot an instrument approach while at the same time looking out the window for the runway.
Area Navigation (RNAV) usually refers to an equipment that offers navigational flexibility by allowing aircraft to proceed directly from any location to any other desired point – point to point route.
Please remember that: the shortest distance between two points on the earths surface is “great circle distance”
Waypoint is a geographical location that can be described by latitude and longitude or, when associated with a VOR station, by radial and DME distance.
VOR/DME-based RNAV means that waypoints are selected by radial and DME from a “parent” VOR – these waypoints may be anywhere, provided that they are within the operational service volume of the “partent” VOR.
Global Positioning System (GPS) receives navigational inputs from a space-based constellation of more than 2x geostationary satellites. The benefit of GPS is its accuracy and its operation basically doesn’t require ground-based Nav stations (except for precision approaches).
The GPS computer onboard determines aircraft location by using timing radio signals received from 4 or more GPS satellites, then it calculates the aircraft’s position and velocity three-dimensionally by comparing satellite positions and times of transmission, and synchronizing that information with an internal clock.
Inertial Navigation System (INS) receives no navigational signals from outside the aircraft – it is a standalone onboard system of which computer determines location, ground speed, heading, and altitude through using accelerometers (a system of acceleration sensors). The major benefit of INS is its accuracy without being subject to interference from weather, or failure of any ground based stations.
However, INS is needed to be set prior to takeoff, and the longer the operations, the more erros the system will accumulate. Therefore, the FMC continuously updates INS position information by automatically tuning the aircraft’s VOR/DME radios for position updates.
“map shift” is the difference between displayed position and actual aircraft/route/waypoints/NAVAID position.
Required Navigation Performance (RNP) is a system of RNAV navigation incorporating an airborne monitoring and alerting system to notify the flight crew when certain navigational performance criteria (i.e RNP specification) cannot be met.
RNP is presented as a value. For example, an RNP of 0.3 means a navigation system must be able to calculate the aircraft’s position to within a circle with a radius of 0.3NM for 95% of the flight time.
ANP value should ALWAYS be less than RNP (ANP < RNP!)
Actual Navigation Performance (ANP) means the value determined by the airborne monitoring and alerting system. The lower the ANP number, the more confident the navigation systems is of its position.
“Equator” is defined as the 0-degree reference of the “Parallels of latitude” lines;
“Prime meridian” is definded a the 0-degree reference of the “Meridians of longitude” lines
Flight Management System (FMS) consists of :
- Air Data Computer
- NAV computer and
- a series of actuation systems
The FMS uses computer technology and linked flight control devices (e.g autopilot, flight director and auto-throttle) to aid the flight crew in flying the aircraft.
Flight Management Computer (FMC) stores different databases (e.g navigation database, terrain database ,and aircraft performance database) that are useful in processing to generate information. Then the FMC directs the FMS’s autopilot/flight director system and engine auto-throttles to achieve lateral navigation (LNAV) and vertical navigation (VNAV).
Control Display Unit (CDU) is basically a minicomputer terminal that allows crews to:
- input NAV and performance data,
- select NAV and performance options, and
- read NAV and performance information from display
Basic operation of a generic FMS is quite simply. During preflight, the crews need to input data on CDU’s pages which are presented in a logical sequence. Now, let us take a look on an example – a sequence of pages:
- “identification page” – the first page with aircraft type, software version, engine type & rated thrust information, and NAV database valid period
- “alignment page” – allow crews to input the coordinates of current location to initialize the INS function
- “route page” – allow crews to input the details of the planned route and the FMC will check for completeness (no gaps)
- “performance page” – allow crews to input the details of gross weight, fuel load, OAT, wind data, preferred cruise altitude etc. The FMC then will calculate takeoff “V-speeds” and the FMC may even generate “command bugs (command markers)” on EFIS.
Upon takeoff, the FMS Nav system will automatically and continuously update the aircraft’s position and direct the controls; When reaching the destination, the FMC will execute the entire transition from cruise to landing, including profile descent, instrument approaches and even touchdown and braking.
Controller-Pilot Data-Link Communications (CPDLC) is a air-to-ground data-link application enabling the exchange of text messages between controllers and pilots. CPDLC utilized SATCOM – it is in the same manner as the crew receives messages over the ACARS.
CPDLC complements traditional VHF (line-of-sight) or HF (long-distance) voice communications, providing an additional means of communication.
Automatic Dependent Surveillance-Broadcast (ADS-B) is a transponder-based system where both pilots and controllers see radar-like displays with accurate traffic data, real-time weather, and terrain information displays. Be noticed that ADS-B does not take the place of TCAS system! In contrast, ADS-B is an advisory-only application designed for controllers “see” air traffic – it is particular useful in non-radar environments.
In the Chapter 14, we can know the basic of different hazard avoidance systems
Radar is an acronym for RAdio Detection And Ranging. There are two basic components: transmitter and receiver.
- The transmitter (highly directional antenna) sends out a cone-shaped energy pulse – high-frequency (HF) RF (radio frequency)
- The cone-shaped energy pulse travels at the speed of light until it strikes something, such as droplets
- Some energy (“return”/”echo”) is reflected back to the receiver. The receiver is actually connected to a signal processor that calculate distance and direction of the “return”/”echo” and display on screen as information
As mentioned above, the HF RF energy pulse is in cone-shaped. In order to cover more area with the beam, an electric motor automatically and continuously “scans” back and forth in horizontal plane (azimuth). In some cases, this “azimuth scan” is set by the manufacturer (cover about 60 degrees either side of the aircraft’s nose) and cannot be controlled by the crews.
Be noticed that many radar systems incorporate “antenna gyro-stabilization” features to compensate the changes of aircraft attitude – whenever the aircraft banks, the azimuth scan will be affected if there is no such stabilization function.
Meanwhile, the “vertical scan” can be controlled by the crews. The crews can adjust the tilted angle (a.k.a. “elevation”/ vertical angle) of the radar (usually +/- 10 degrees from the longitudinal axis of the aircraft).
In terms of the radar antenna, there are 2 common types:
- produce larger radar beam (beam width is bigger) – allowing broader coverage with a smaller antenna
- but offering relatively less range
- often found in smaller aircraft
- flat plate
- produce smaller radar beam (beam width is smaller)
- but offering relatively longer range
- often found in large aircraft
Significance (meaning) of radar return/echo
Modern radar indicators usually display returns in 3 or 4 colors to differentiate between intensity levels.
Green: indicates areas of light rainfall
Yellow: indicates areas of moderate rainfall
Red: indicates areas of heavy precipitation
Magenta/ Flashing Red: indicates areas of very heavy precipitation
“Precipitation Gradient” refers to the distance from the outer edge of a precipitation area to its core.
“Steep precipitation gradients” imply turbulence and vertical wind shear – therefore, STAY AWAY from areas where precipitation returns go from light (green) to heavy (red) over a very short distance.
“Radar shadow” is an area of severe attenuation, generally identified by a complete blackout of data behind a weather cell. These areas actually results from precipitation so heavy that radar is prevented from penetrating to the airspace behind it. Therefore, it is very likely that a strong storm hiding behind that wall of precipitation. NEVER fly toward a radar shadow.
Echo shapes are also indicators of danger areas – odd shapes like “hooks” and “fingers”, “square corners”, “hourglass shapes”, “ragged edges/fragmentation” imply vertical wind shear and turbulence and even hail. Therefore, NEVER fly toward and STAY AWAY from these areas.
In general, the best plan is to avoid storm cells by at least 20NM, and preferably to the upwind side.
Radar operations on ground
NEVER operate radar on the ground (except in standby or test modes). It is because the energy pulse send out from the radar can injure people, damage electronic equipment in other aircraft, and present a hazard during refueling;
For use on takeoff, the radar antenna tilt should be raised so that the beam doesn’t strike the ground.