Question 103-1 : The pilot of a single engine aircraft has established the climb performancethe carriage of an additional passenger will cause the climb performance to be ? [ Exam pilot ]

Question 103-2 : An extract of the flight manual of a single engine propeller aircraft is reproduced in annexairport characteristics hard dry and zero slope runwayactual conditions are pressure altitude 1 500 ftoutside temperature +18°cwind component 4 knots tailwindfor a take off mass of 1 270 kg the take off ?

465 m.

10991270 kg = 2800 lbsconvert 1520 ft to meters 1520 x 03048 = 463 m

Question 103-3 : With regard to the landing chart for the single engine aeroplane determine the landing distance from a height of 50 ftgiven oat isapressure altitude 1000 ftaeroplane mass 3500 lbstailwind component 5 ktflaps landing position down runway tarred and dry 2136 ?

Approximately 1700 feet.

1102you will find 1760 ft close enough to 1700 feet

Question 103-4 : With regard to the take off performance chart for the single engine aeroplane determine the take off distance to a height of 50 ftgiven oat 30°cpressure altitude 1000 ftaeroplane mass 3450 lbstailwind component 25 ktflaps uprunway tarred and dry 2134 ?

Approximately 2470 feet.

1131

Question 103-5 : For this question use reference or performance manual sep 1 figure 21with regard to the take off performance chart for the single engine aeroplane determine the maximum allowable take off massgiven oat isapressure altitude 4000 ftheadwind component 5 ktflaps uprunway tarred and dryfactored runway ?

3240 lbs.

Complete the graph with the data com encom032 359jpgyou will find 3240 lbs

Question 103-6 : Consider the graphic representation of the power required versus true air speed tas for a piston engined aeroplane with a given masswhen drawing the tangent from the origin the point of contact a determines the speed of 2133 ?

Maximum specific range.

1085maximum specific range is reached at minimum drag speed vmd for a piston engined aeroplane 1135vmd is the speed for maximum range in a prop aircraftvmd is the speed for maximum endurance in a jet aircraft

Question 103-7 : For this question use reference sep 1 figure 23using the climb performance chart for the single engine aeroplane determine the ground distance to reach a height of 1500 ft above the reference zero in the following conditions given oat at take off isaairport pressure altitude 5000 ftaeroplane mass ?

15640 ft.

At 5000 ft isa t° is 5°c15001080= 139 minuteground speed 100 + 5 = 105 kt 10560 x 139 = 243 nm243 = 45 km = 14722 ft com encom032 362jpgclosest answer is 15640 ft normally we should use the climb gradient since the question gives a speed in ias but rate of climb can also lead closely to the correct answer ebbr1000 tas= 108 ktheight difference x 100 climb gradient= 1500 x 100 99 = 15151 ft 15151 x gs tas= 15151 x 113 108 = 15852 ft

Question 103-8 : For this question use referenceusing the climb performance chart for the single engine aeroplane determine the rate of climb and the gradient of climb in the following conditions given oat at take off isaairport pressure altitude 3000 ftaeroplane mass 3450 lbsspeed 100 kias err a 032 363 ?

1140 ftmin and 106%.

Isa at 3000 ft 15° 2° x 3 = +9°cfor a given ias the true airspeed is about 2% higher than ias per 1000ft of altitude above sea level com encom032 363jpgrate of climb 1140 ftmingradient of climb 106% atplea figure cap698 figure 23

Question 103-9 : At reference or use performance manual sep 1 figure 21airport characteristics hard dry and runway slope zeroactual conditions are pressure altitude 1500 ftoutside temperature +18°cwind component 4 kt tailwindfor a take off mass of 2800 lbs the take off distance will be err a 032 405 ?

1500 ft.

Img com encom032 405png

Question 103-10 : Unless otherwise specified in the afm for a performance class b aeroplane landing on a downhill runway what factor must be applied for each 1% of downslope ?

105.

Ecqb04 october 2017the factor to be applied for each 1% of downslope is 5% or 105

Question 103-11 : Unless otherwise specified in the afm for a performance class b aeroplane taking off on a uphill runway what factor must be applied for each 1% of uphill slope ?

Question 103-12 : The following conditions are observed at an airport runway 13 wind 140° for 30 kta pilot can determine a crosswind component of ?

5 kt.

Vt = sin 10° x 30 = 5 kt

Question 103-13 : Maximum crosswind demonstrated is equal to 02 vs0 and the following conditions are observed at an airport vs0 70kt landing runway 35 wind 300° for 20 kt ?

.

350 300=50°crosswind sin50x20=153ktdemonstrated crosswind 70x02=14kt

Question 103-14 : Which margin above the stall speed is provided for the landing speed reference vref ?

130 vso.

Question 103-15 : Unless otherwise specified when landing on a runway with a downslope of 2% the landing distances required should be increased by ?

10%.

Regulation eu no 9652012annex iv part cat amc2 catpola330 landing – dry runwaysrunway slope unless otherwise specified in the afm or other performance or operating manuals from the manufacturer the landing distances required should be increased by 5% for each 1% of downslope in this case downslope of 2% therefore the landing distances required should be increased by 5 x 2% = 10%

Question 103-16 : A pilot is calculating the take off distance for a performance class b multi engined aeroplane specific factors must be applied to the afm data to take into account variables that affect the take off performancethese factors have not been provided in the afm and other performance and operating ?

Surface type grass condition wet or dry.

If the runway surface is other than dry and paved the following factors must be used when determining the take off distance surface type condition factor grass on firm soil up to 20 cm long dry x 12 wet x 13 paved wet x 10

Question 103-17 : How does a change in pressure altitude influence the landing distance and ground roll distance ?

Higher pressure altitude results in an increased landing distance required and an increased ground roll distance.

The air density affects the tas for a given ias a higher pressure altitude will give an increase in landing distance due to the higher tas for the same ias

Question 103-18 : The combination of factors that most requires a low angled flap setting for take off is ?

High field elevation distant obstacles in the climb out path long runway and a high ambient temperature.

Effect of flaps on landingtake off run and climb gradientthe use of high life devices flaps will have an impact on the take off and landing roll and climb gradientfor a given runway length and airplane weight selecting a greater flap setting will increase the lift coefficient which reduces the stalling speed as a consequence the take off speeds are reduced the same lift will be created at smaller air speed due to greater lift coefficient this will reduce the take off run therefore it makes sence to select a higher flap setting when taking off from a short runway flap extension during landings provides several advantages by producing greater lift and permitting lower landing speedproducing greater drag permitting a steep descent angle without airspeed increase=> reducing the length of the landing rollthe down side of the use of flaps is that it generates more parasite drag we get our best angle of climb and therefore our best gradient where there is the biggest gap between the thrust available and thrust required the parasite drag from the extended flap closes the gap and the climb angle and climb gradient will reduce and go around performance is deteriorated hence as soon as we can after take off we accelerate and retract the flap and climb clean=> using a low flap setting is recommended when distance obstacles are presentusing less flaps would provide a better climb gradient but with the cost of a longer take off run therefore if we have a long runway and obstacles at distance less flap setting should be used in addition to this at higher altitudes and temperatures thrust will be less thus take off run is longer using lower flaps also decreases drag and acceleration is faster this combination is the most suitable for low flap settings

Question 103-19 : The effect that a tailwind has on the value of the maximum endurance speed is ?

None.

Wind influence on range and endurancerangewind speed is an important practical influence on gliding distance over the surface with a tailwind the glide distance achieved will be increased as a result of the increased groundspeed whereas with a headwind it will be reduced because of the consequently slower groundspeedendurance the wind has no effect on endurance endurance is about time in the air not distance covered maximum endurance is concerned with minimizing fuel flow and wind does not affect the fuel flow into the engine as long as it has usable fuel in its tanks an aircraft will still remain airbornesummary range glide distance varies with wind => tailwind increases glide distance=> headwind decreases glide distanceendurance glide duration varies with mass => low mass increases glide duration=> high mass decreases glide duration

Question 103-20 : What is the minimum speed at 50 ft above the take off surface for a single engine aeroplane with a vs1 of 67 kt ?

81 kt.

Cs23 states that the minimum speed at the screen height of 15m50ft for a single engine class b aircraft is a 'safe speed' or 12vs167kts x 12 = 804kts rounded up to 81 kts

Question 103-21 : The critical engine of a multi engined propeller driven aeroplane is the one whose failure would result in the most adverse effect on the aeroplane’s ?

Handling and performance characteristics.

Critical engine of a multi engine fixed wing propeller driven aircraft is defined as the one whose failure would most adversely affect the performance or handling qualities of an aircraft for a multi engine airplane the largest asymmetric thrust moment occurs when an outboard engine fails that engine failure which most adversely affects the performance is deemed the critical power unit and is used to determine the limiting control speeds that will ensure adequate directional control in such an event for propeller driven airplanes the direction of propeller rotation determines the critical engine viewed from behind a clockwise rotation dictates that the outboard left engine is critical

Question 103-22 : A twin engine piston aeroplane with all engines operating commences take off and the following information is given maximum take off mass 4 750 kg airport elevation 500 ft obstacle elevation 644 ft distance from the end of the take off distance to the obstacle 2 000 m temperature isa qnh 1 018 ?

50 ft.

Obstacle clearancein eu ops it states that an operator must ensure that the net take off flight path must clear all obstacles by a vertical margin of 35 ft for class a airplanes to 50 ft for class b airplanes if the airplane is unable to do so it must turn away from the obstacle and clear it by a horizontal distance of at least 90 m + 0125d where d is the distance from the end of the toda or the end of the tod if a turn is scheduled before the end of the toda for airplanes with a wingspan of less than 60 m the horizontal distance may be taken as 60 m + half the wingspan + 0125dannex i – definitions 93 'performance class a aeroplanes' means multi engined aeroplanes powered by turbo propeller engines with an mopsc of more than nine or a maximum take off mass exceeding 5 700 kg and all multi engined turbo jet powered aeroplanes 94 'performance class b aeroplanes' means aeroplanes powered by propeller engines with an mopsc of nine or less and a maximum take off mass of 5 700 kg or less 95 'performance class c aeroplanes' means aeroplanes powered by reciprocating engines with an mopsc of more than nine or a maximum take off mass exceeding 5 700 kgmopsc = maximum operational passenger seating configuration multi engine jetpropeller drivenmulti engineturboproppistonmass > 5700 kgorpassenger seats > 9aacmass 5700 kgandpassengers seats 9abb

Question 103-23 : How does the thrust of a propeller vary during take off run assuming unstalled flow conditions at the propeller blades the thrust ?

Decreases while the aeroplane speed builds up.

The engine thrust will vary during take off and the variation of thrust with speed will be different for jet and propeller engines jet engine for a jet engine the net thrust is the difference between the gross thrust and the intake momentum drag increasing speed increases the intake momentum drag which reduces the thrust however at higher speeds the increased intake pressure due to ram effect helps to reduce this loss of thrust and eventually at very high speeds it will cause the net thrust to increase again during take off the airplane speed is still low and as such the ram effect is insufficient to counteract the loss of thrust due to intake momentum drag therefore during the take off there will be a decrease of thrust propeller for a propeller driven aircraft thrust is produced by a propeller converting the shaft torque into propulsive force for a fixed pitch propeller angle of attack decreases as forward speed increases thrust therefore decreases with increasing speed for a variable pitch propeller the propeller will initially be held in the fine pitch position during take off and the propeller angle of attack will decrease with increasing speed above the selected rpm the propeller governor will come into operation increasing the propeller pitch and reducing the rate at which the thrust decreases in summary therefore the thrust of a propeller airplane decreases with forward speed

Question 103-24 : An aeroplane with reciprocating engines is flying at a constant angle of attack mass and configuration with increasing altitude the drag ?

Remains unchanged but the tas increases.

The drag curve is plotted as an eas which is the same as cas except for the effect of compressibility at speeds near vmd compressibility is insignificant so eas can be thought of as being the same as ias or cas the drag curve plotted against eas remains unchanged with altitude and temperature for a given angle of attack mass and configurationalso for a fixed ias as the aircraft climbs at higher altitudes thus less dense air then the tas increases progressively

Question 103-25 : In the drift down for an aeroplane in performance class b the net gradient of descent is assumed to be gross gradient of descent by ?

Increased 05%.

Multi engine class b en route requirement the aeroplane in the meteorological conditions expected for the flight and in event of the failure of one engine with the remaining engines operating within the maximum continuous power conditions specified shall be capable of continuing flight at or above the relevant minimum altitudes for safe flight stated in the operations manual to a point of 1000 ft above an aerodrome at which the performance requirements can be met it shall be assumed that at the point of engine failure the aeroplane is not flying at an altitude exceeding that at which the rate of climb equals 300 ft per minute with all engines operating within the maximum power conditions specified and the en route gradient with oei shall be the gross gradient of descent or climb as appropriate respectively increased by a gradient of 05% or decreased by a gradient of 05%

Question 103-26 : Which of the following requirements must be met by a mep performance class b aircraft landing on dry runways the actual landing distance shall be less than ?

07 x lda.

Easa air opschapter 3 performance class bcatpola330 landing — dry runways a the landing mass of the aeroplane determined in accordance with catpola105 a for the estimated time of landing at the destination aerodrome and at any alternate aerodrome shall allow a full stop landing from 50 ft above the threshold within 70 % of the lda taking into account 1 the altitude at the aerodrome 2 not more than 50 % of the headwind component or not less than 150 % of the tailwind component 3 the runway surface condition and the type of runway surface and 4 the runway slope in the direction of landingnote 60% 06 of the landing distance available for turbojet airplanes70% 07 of the landing distance available for turboprop airplanes

Question 103-27 : How does an approach and landing with full flaps compare to one with zero flaps the full flap approach and landing will have a ?

Slower approach speed and shorter ground roll distance.

effect of flaps on landingtake off run and climb gradient the use of high life devices flaps will have an impact on the take off and landing roll and climb gradientfor a given runway length and airplane weight selecting a greater flap setting will increase the lift coefficient which reduces the stalling speed as a consequence the take off speeds are reduced the same lift will be created at smaller air speed due to greater lift coefficient this will reduce the take off run flap extension during landings provides several advantages by producing greater lift and permitting lower landing speed producing greater drag permitting a steep descent angle without airspeed increase => reducing the length of the landing rollthe down side of the use of flaps is that it generates more parasite drag we get our best angle of climb and therefore our best gradient where there is the biggest gap between the thrust available and thrust required the parasite drag from the extended flap closes the gap and the climb angle and climb gradient will reduce => go around performance is deteriorated hence as soon as we can after take off we accelerate and retract the flap and climb clean

Question 103-28 : If the air temperature decreases the take off distance ground roll distance will… ?

Decrease decrease.

Although an increase in temperature slightly reduces air density and therefore mass flow in practice it is either the tgt limit or rpm limit that restricts the available thruston hot days above isa + 15°c the tgt limit is reached firstif the outside air temperature gets hotter the tgt is reached at a slightly slower rpm resulting in the mass flow and thrust available reducingconversely the thrust available increases as the outside air temperature gets colderthis is because the rpm at which the tgt becomes limiting is faster and therefore the mass flow is greatertherefore as temperature increases above isa + 15°c thrust reducesthe red line in the graph below shows thishowever at outside air temperatures below isa + 15°c the rpm limit is reached firstprovided the thrust is regulated by the rpm limit the thrust does not change with temperaturethis is shown by the blue line in the above graphthe rpm can be limited manually by a flight engineer but is normally achieved today electronically by flat rating the engine below isa + 15°cvice versa for the conditions mentioned above if temperature decreases it will effect pozitive for the performance

Question 103-29 : How is take off performance affected by using flaps 10° instead of flaps 5° ?

Ground roll is decreased drag is increased climb performance is decreased.

Effect of flaps on landingtake off run and climb gradientthe use of high life devices flaps will have an impact on the take off and landing roll and climb gradientfor a given runway length and airplane weight selecting a greater flap setting will increase the lift coefficient which reduces the stalling speed as a consequence the take off speeds are reduced the same lift will be created at smaller air speed due to greater lift coefficient this will reduce the take off run flap extension during landings provides several advantages by producing greater lift and permitting lower landing speedproducing greater drag permitting a steep descent angle without airspeed increase=> reducing the length of the landing rollthe down side of the use of flaps is that it generates more parasite drag we get our best angle of climb and therefore our best gradient where there is the biggest gap between the thrust available and thrust required the parasite drag from the extended flap closes the gap and the climb angle and climb gradient will reduce => go around performance is deteriorated hence as soon as we can after take off we accelerate and retract the flap and climb clean

Question 103-30 : How does a high altitude runway affect the v1 the take off distance and the landing distance ?

V1 – decreases take off distance – increases landing distance – increases.

Air density as air density decreases altitude increases both engine and aerodynamic performance decrease aircraft performance depends on air density which directly affects lift and drag engine power and propeller efficiency as air density decreases altitude increases both engine and aerodynamic performance decrease take off distancewhen an aircraft is taking off at a pressure altitude above isa sea level it will still get airborne at the same indicated airspeed ias as at sea level but because of the lower air density the true airspeed tas will be greater to achieve this higher speed with the same engine power a longer take off run will be needed landing distancebecause of the lower air density the same indicated airspeed will have a higher true airspeed tas which will result in an increased landing run v1 v1 cannot be allowed to be less than vmcg because engine failure below vmcg means the airplane is uncontrollable and the definition of v1 is that the take off can be continued following engine failure at higher altitudes the air is less dense which results in a decreased vmcg consequently v1 will also decrease

Question 103-31 : During take offs for a twin engine aircraft with wing mounted engines both being right hand props which of the following conditions is the most favourable handling wise ?

Left quartering wind and right engine failure.

Asymmetric blade effect also known as ‘p’ factor propeller blades are not flat they are in fact shaped as small wings as a consequence as the angle of attack of the airplane increases the air passing by hits the blades differently the down going blade viewed from the cockpit will have a larger angle of attack compared to the up going blade generating more thrust this then means that the down swinging blade exerts a greater force than the up going blade for this reason the thrust line will be displaced to the right of the engine centre line propellers rotating in the same direction clockwise if both engines rotate clockwise the right engine will have a longer thrust arm than the left engine this difference in thrust will give a yawing moment to the left with a clockwise rotating propeller in a nose up attitude the failure of the left hand engine will result in a larger yaw effect via the operating right hand engine rather than vice versa the left engine is therefore the critical engine => for this reason a failure of the right engine would be most favourablea right engine failure requires a lot of left rudder a condition where left wind is present would reduce the required left rudder => remember that left wind results in left yaw

Question 103-32 : Fill in the blanks for an aeroplane in performance class b the net take off flight path begins at a height of 1 and ends at a height of 2 ?

1 50 ft 2 1 500 ft.

Easa air ops regulation eu no 3792014 chapter 3 – performance class b catpola310 take off obstacle clearance – multi engined aeroplanes a the take off flight path of aeroplanes with two or more engines shall be determined in such a way that the aeroplane clears all obstacles by a vertical distance of at least 50 ft or by a horizontal distance of at least 90 m plus 0125 × d where d is the horizontal distance travelled by the aeroplane from the end of the toda or the end of the take off distance if a turn is scheduled before the end of the toda except as provided in b and c for aeroplanes with a wingspan of less than 60 m a horizontal obstacle clearance of half the aeroplane wingspan plus 60 m plus 0125 × d may be used it shall be assumed that 1 the take off flight path begins at a height of 50 ft above the surface at the end of the takeoff distance required by catpola305 b and ends at a height of 1 500 ft above the surface 2 the aeroplane is not banked before the aeroplane has reached a height of 50 ft above the surface and thereafter the angle of bank does not exceed 15° 3 failure of the critical engine occurs at the point on the all engine take off flight path where visual reference for the purpose of avoiding obstacles is expected to be lost 4 the gradient of the take off flight path from 50 ft to the assumed engine failure height is equal to the average all engines gradient during climb and transition to the en route configuration multiplied by a factor of 077 and 5 the gradient of the take off flight path from the height reached in accordance with a 4 to the end of the take off flight path is equal to the oei en route climb gradient shown in the afm

Question 103-33 : For an sep in the utility category taking off on a dry paved runway the minimum value of vr is ?

Vs1.

Cs 2351 take off speeds a for normal utility and aerobatic category aeroplanes the rotation speed vr is the speed at which the pilot makes a control input with the intention of lifting the aeroplane out of contact with the runway or water surface 1 for twin engined landplanes vr must not be less than the greater of 1·05 vmc or 1·10 vs1 2 for single engined landplanes vr must not be less than vs1 and 3 for seaplanes and amphibians taking off from water vr must be a speed that is shown to be safe under all reasonably expected conditions including turbulence and complete failure of the critical engine

Question 103-34 : For class b aircraft the obstacle accountability area is defined as ?

The area beyond the toda within which obstacles are considered for the purposes of takeoff climb performance.

Obstacle accountability areaobstacles are considered if they lie in an area called the 'obstacle accountability area'for aircraft with a wing span of less than 60m semi width of such area is calculated 125d+ 60 m + half the wingspan if the flight path requires a change of track direction between 0 and 15 deg then the area reaches a maximum semi width of 300m if the flight path requires a change of track direction above 15 deg then the area reaches a maximum semi width of 600mfor aircraft with a wing span of more than 60m semi width of such area is calculated 0125 d + 90 md = horizontal distance travelled from the end of toda or tod

Question 103-35 : For a single engine aeroplane calculate the net glide distance following an engine failure given altitude 9500 ftterrain elevation 500 ftgross gradient 11%tas 250 kttailwind 50 ktstill air distance = height difference ft x 100 net gradient % ground distance = still air distance x gstas ?

155 nm.

The question asks for the net distance which means that we can use the net gradient air ops states that for the purpose of flight planning the gross glide gradient to reach such places where the aeroplane can safely land must be increased by 05%net gradient = gross gradient + 05% = 115%now let’s calculate the net glide distance still air distance = height difference ft x 100 net gradient % still air distance ft = 9 000 x 100 115 = 78 261 ft 78 261 ft 6076 = 129 nm ground distance = still air distance x gstas ground distance = 129 x 300250 ground distance = 155 nm

Question 103-36 : Following a take off determined by the 50 ft 15m screen height a light twin climbs on a 10% over the ground climb gradient determine the obstacle clearance above a 215 m high obstacle in relation to the runway horizontally situated at 3000 m from reference zero ?

100 m.

Use the following formula gradient = change in height distance travelled x 100 change in height = gradient x distance travelled 100 change in height = 10 x 3 000 100 change in height = 300 maircraft height at obstacle 300 m + screen height = 300 m + 15 m = 315 m obstacle clearance = 315 m 215 m = 100 m

Question 103-37 : For a multi engine class b aircraft all engines operating the take off flight path is equal to the gross gradient of the actual flight path ?

Multiplied by 077.

'the gradient from 50 ft to the assumed engine failure height is the average all engine gradient x 077' the class b net take off flight path calculation for calculating the regulatory obstacle clearance assumes an all engine climb to the cloud base then an engine out climb to 1 500 ft above the aerodromethe all engine gross gradient is reduced to net gradient by multiplying it by 077

Question 103-38 : For planning purposes determine the net distance travelled down to 4 000 ft for a single engine piston aircraft following an engine failure at 8 000 ft given the following data tas 120 kts gs 150 kts gross gradient of descent 11% grossnet gradient decrement 05% still air distance ft = height ?

71 nm.

The question asks for the net distance which means that we can use the net gradientair ops states that for the purpose of flight planning the gross glide gradient to reach such places where the aeroplane can safely land must be increased by 05%net gradient = gross gradient + 05% = 115%now let’s calculate the net glide distance still air distance = height difference ft x 100 net gradient % still air distance ft = 4 000 x 100 115 = 34 783 ft 34 783 ft 6076 = 57 nm ground distance = still air distance x gstas ground distance = 57 x 150120 ground distance = 71 nm

Question 103-39 : A single engine class b aeroplane has the following wind limitations crosswind 17 kt headwind 30 kt tailwind 10 kt consider a take off from runway 20 with wind from 265° using trigonometry determine the wind speed which allows to stay below the crosswind limit of 17 kt ?

18 kt.

The wind components may be calculated using sin or cossin a = opposite side hypotenusethe angle between the wind and the runway direction is 65ºwe need to calculate the hypotenuse of a triangle whose opposite side crosswind equals 17 kt hypotenuse = 17 sin 65 = 1875 kt to stay below the limit 18 kt would be the correct answer

Question 103-40 : For a single engine aeroplane calculate the net glide distance following an engine failure given altitude 9 000 ftterrain elevation 250 ftgross gradient 11%tas 101 kttailwind 3 ktstill air distance = height difference ft x 100 net gradient % ground distance = still air distance x gstas ?

129 nm.

The question asks for the net distance which means that we can use the net gradientair ops states that for the purpose of flight planning the gross glide gradient to reach such places where the aeroplane can safely land must be increased by 05%net gradient = gross gradient + 05% = 115%now let’s calculate the net glide distance still air distance = height difference ft x 100 net gradient % still air distance ft = 8 750 x 100 115 = 76 087 ft 76 087 ft 6076 = 1252 nm ground distance = still air distance x gstas ground distance = 1252 x 104101 ground distance = 129 nm