Aircraft Limitations

Question 1

What is Vmo or Mmo?

Answer 1

MAXIMUM OPERATING LIMIT;

The SPEEDS that may NOT be DELIBERATELY EXCEEDED in any regime of flight (Climb, cruise or descent)

Question 2

What is Vfe?

Answer 2

FLAP EXTENDED SPEEDS;

SPEEDS that may NOT be EXCEEDED because of FLAP DESIGN LIMITS

Question 3

What is Vlo?

Answer 3

LANDING GEAR OPERATING SPEED;
LIMIT for which below it is SAFE to both EXTEND and RETRACT landing GEAR;
If EXTENSION and RETRACTION SPEEDS are different they are designated as Vlo(EXT) and Vlo(RET)

Question 4

What is Vle?

Answer 4

LANDING GEAR EXTENDED SPEED;

LIMIT for which below it is safe to fly with LANDING GEAR secured in the FULLY EXTENDED POSITION

Question 5

What is Vmcg?

Answer 5

MINIMUM CONTROL SPEED on the GROUND;
The CALIBRATED airspeed during takeoff RUN at which, when CRITICAL ENGINE is SUDDENLY INOPERATIVE it is possible to MAINTAIN CONTROL of aeroplane using PRIMARY AERODYNAMIC CONTROLS ALONE for takeoff to continued SAFELY using NORMAL piloting SKILL

Question 6

How is Vmcg determined?

What are the conditions for determining Vmcg?

Answer 6

The path from which the CRITICAL ENGINE is made INOPERATIVE to a point where RECOVERY PARALLEL to the CENTRELINE is completed may NOT DEVIATE MORE than 30ft LATERALLY;
TAKEOFF CONFIGURATION or in the MOST CRITICAL TAKEOFF CONFIGURATION;
MAXIMUM AVAILABLE takeoff POWER or THRUST;
MOST UNFAVOURABLE CoG;
TRIMMED for TAKEOFF;
MOST UNFAVOURABLE WEIGHT in takeoff weight range

Question 7

What is Vmca?

Answer 7

MINIMUM CONTROL SPEED in AIR;
The CALIBRATED airspeed when CRITICAL engine is SUDDENLY INOPERATIVE, it is possible to MAINTAIN CONTROL and maintain STRAIGHT flight with ANGLE of BANK NOT MORE than 5 degrees

Question 8

What are the conditions where Vmca must not exceed 1.2 Vs?

Answer 8

MAX available TAKEOFF POWER/THRUST;
MOST UNFAVOURABLE CoG;
TRIMMED for TAKEOFF;
MAX SEA-LEVEL TAKEOFF WEIGHT;
MOST CRITICAL TAKEOFF CONFIG after airborne except with GEAR RETRACTED;
Aeroplane AIRBORNE and NEGLIGIBLE GROUND EFFECT;
Must not assume any DANGEROUS ATTITUDE or a HEADING CHANGE of MORE THAN 20 degrees

Question 9

What is Vmcl?

Answer 9

MINIMUM CONTROL SPEED for APPROACH and LANDING;
The CALIBRATED airspeed when CRITICAL engine SUDDENLY INOPERATIVE it is possible to MAINTAIN CONTROL and maintain STRAIGHT flight with ANGLE of BANK NOT MORE than 5 degrees

Question 10

What must Vmcl be established with?

Answer 10

MOST CRITICAL CONFIG for APPROACH and LANDING with ALL ENGINES operating;
MOST UNFAVOURABLE CoG;
TRIMMED for APPROACH with ALL ENGINES operating;
MOST UNFAVOURABLE WEIGHT;
GO AROUND THRUST SETTING on operating ENGINES;
LATERAL CONTROL sufficient to ROLL from STEADY STRAIGHT through 20 degrees AWAY from INOPERATIVE ENGINE in NO MORE than 5 seconds

Question 11

What is Vmu?

What are the 2 different Vmu? What is the relationship between the 2?

Answer 11

MINIMUM UNSTICK SPEED;
The CALIBRATED airspeed AT and ABOVE the aeroplane can SAFELY LIFT OFF and continue TAKE OFF;
Vmu(N): ALL ENGINES operative;
Vmu(N-1): 1 ENGINE inoperative;
Vmu(N) =/< Vmu(N-1)

Question 12

What is Vmu limited by?

Answer 12

For LONGER aeroplanes: TAILSTRIKE;

For SHORTER aeroplanes: STALL/MAX CL

Question 13

What is the difference between Vs1g/Vsr and Vs?

Answer 13

Vs1g/Vsr: STALL SPEED when CL is MAX and LOAD FACTOR is EQUAL to 1 used by FLY BY WIRE aeroplanes;
Vs: CONVENTIONAL STALL when LIFT suddenly COLLAPSES and LOAD FACTOR becomes LESS than 1

Question 14

What is the relationship between Vs and Vs1g?

Answer 14

Vs = 0.94 x Vs1g

Question 15

What is DOW?

Answer 15

DRY OPERATING WEIGHT;

The TOTAL WEIGHT of an aircraft ready for an operation EXCLUDING ALL USABLE FUEL and TRAFFIC LOAD

Question 16

What is ZFW?

Answer 16

ZERO FUEL WEIGHT;
The WEIGHT of TOTAL TRAFFIC LOAD (payload including cargo loads, passengers and passenger’s bags) PLUS the DRY OPERATING WEIGHT ie: DOW + TRAFFIC LOAD

Question 17

What is LW?

Answer 17

LANDING WEIGHT;
The WEIGHT LANDING at DESTINATION;
ZFW + RESERVES

Question 18

What is TOW?

Answer 18

TAKEOFF WEIGHT;
The WEIGHT at TAKEOFF at departure;
LW + TRIP FUEL or;
ZFW + TAKEOFF FUEL (fuel needed at the brake release point including reserves)

Question 18

What is taxi/ramp weight?

Answer 18

TOW + TAXI FUEL

Question 19

How is max takeoff weight determined?

Answer 19

FLIGHT STRUCTURE RESISTANCE criteria;
RESISTANCE of landing GEAR;
STRUCTURE criteria during a LANDING IMPACT with a VERTICAL SPEED equal to -1.83 m/s (-360 feet/min)

Question 20

How is max landing weight determined?

Answer 20

By a LANDING IMPACT with a VERTICAL SPEED equal to -3.05 m/s (-600 feet/min)

Question 21

How can the MTOW and MLW be represented in equations with actual takeoff and landing weights?

Answer 21

ACTUAL LW = TOW - TRIP FUEL =/< MLW;

ACTUAL TOW =/< MLW + TRIP FUEL

Question 22

Why is a MZFW required?

Answer 22

BENDING MOMENTS that apply at WING ROOT are MAX when FUEL is MIN when FUEL DECREASES in flight the MOMENT INCREASES therefore weight with zero fuel must be LIMITED;
ACTUAL TOW =/< MZFW + TAKEOFF FUEL

Question 23

Briefly describe the concept of environmental envelope?

Answer 23

Shows the FLIGHT, STRUCTURAL, POWER PLANT, FUNCTIONAL or EQUIPMENT CHARACTERISTICS at extreme TEMPERATURES and PRESSURE ALTITUDES

Question 24

What is the main cause of engine limitations?

What are the limits for takeoff/go-around, max continuous thrust and climb operating conditions?

Answer 24

EXHAUST GAS TEMPERATURE;
TOGA: MAX 10 minutes with ENIGNE FAILURE, or 5 minutes with ALL ENGINES OPERATIVE;
MCT: UNLIMITED in flight, MUST be selected in ENGINE FAILURE, when TOGA thrust is NOT ALLOWED due to TIME LIMIT
CL: UNLIMITED in CLIMB PHASE to the cruise flight level, is GREATER THAN MAX CRUISE THRUST AVAILABLE during CRUISE PHASE

Question 25

How does temperature and pressure altitude related to takeoff thrust?

Answer 25

TEMPERATURE: At a given PA, TEMPERATURE has NO EFFECT on THRUST until Tref, beyond Tref an INCREASE in TEMPERATURE, leads to a DECREASE in THRUST AVAILABLE due to EGT;
PRESSURE ALTITUDE: At a given TEMPERATURE any INCREASE is PA will cause a DECREASE in THRUST AVAILABLE