TOLD Flashcards
Define Minimum Acceleration Check Speed (MACS)
- The minimum acceptable speed at the check distance with which takeoff can be continued.
- Computed to allow for variations in engine performance due to engine trim, throttle setting (form takeoff), and pilot technique.
- Computed by reducing NACS 3 knots per 1,000 feet that runway length exceeds Critical Field Length (not to exceed a 10 knot decrease).
- Validates the rest of our TOLD data.
Define Refusal Speed (RS)
- The maximum speed to which the aircraft can accelerate with both engines operating in MAX and either: Abort with Both Engines Operating (BEO), or with an Engine Failure (EF).
- RS-BEO accounts for a 3 second reaction time; both engines producing MAX thrust during those 3 seconds; if in the 3-point attitude and below 130 knots, wheel brakes applied such that desired braking is achieved in 2 seconds (use cautious braking between 100 and 130 KCAS and optimum braking below 100 KCAS); if the aircraft has rotated, hold pitch attitude at 7.5 degrees for aerobraking until 120 KCAS, then wheel braking described above after nosewheel settles to the runway.
- RS-EF uses the same assumptions as RS-BEO except for one engine is in MAX and the other is windmilling during 3 second reaction time.
Define Decision Speed (DS)
- The minimum speed at which the aircraft can experience an instantaneous engine failure and still accelerate to SETOS and takeoff in the remaining runway.
- Assumptions include 3 second reaction time; accelerating in a 3 point attitude prior to rotation at SETOS; one engine producing MAX thrust while the other is windmilling; takeoff occurs approximately 700 feet from start of rotation at SETOS.
Define Critical Engine Failure Speed (CEFS)
- The speed to which the aircraft accelerates with both engines, experiences an engine failure, and permits either acceleration to SETOS and takeoff or deceleration to a stop in the same distance.
- Uses the same assumptions as DS and RS-EF
Define Critical Field Length (CFL)
- The total runway length required to accelerate with both engines to CEFS, experience an engine failure, then either continue to takeoff or stop in the same distance.
Define Single Engine Takeoff Speed (SETOS)
- The speed at which the aircraft can climb out of ground effect at a minimum of 100 feet per minute with gear down, flaps at 60% (rotation initiated at SETOS). Minimum SETOS is 2-engine takeoff speed.
- Dash 1 Ch 3 says you get an additional 8-50 FPM for each additional knot of airspeed above SETOS (non-PMP motors only).
- Single engine climb chart shows less than 60 FPM increase for each additional knot.
- Takeoff occurs approximately 700 feet from start of rotation at SETOS.
- Above SETOS + 10, gear door drag is not a factor during retraction.
What are your go/no-go speeds with a remotely controlled BAK-15?
1). DS <= RS-EF –> use RS-EF
2). RS-EF < DS <= TOS –> OG approval, use TOS
3). DS > TOS –> no takeoffs authorized
What are your go/no-go speeds with a raised BAK-15 (not remotely controlled)?
1). DS <= RS-EF –> use RS-EF
2). RS-EF < DS <= TOS –> OG approval, use SETOS, delay rotation until 155 knots and ensure nosewheel off the runway by 174 knots
3). DS >= TOS –> no takeoffs authorized
What are your go/no-go speeds without a BAK-15?
1). DS <= RS-BEO –> use RS-BEO
2). RS-BEO < DS <= RS-EF –> OG approval, use RS-EF
3). DS > RS-EF –> no takeoffs authorized
What happens to takeoff speed (TOS) as:
1). temperature and pressure altitude increase?
2). headwind increases?
3). RCR decreases?
4). weight decreases? Why?
1). temperature and pressure altitude increase?
- No change; while the TAS required for takeoff increases, the IAS for takeoff doesn’t change
2). headwind increases?
- No change; same airflow over the wing required for takeoff (same IAS), but takeoff will occur at a slower groundspeed
3). RCR decreases?
- No change; runway condition doesn’t affect IAS for takeoff
4). weight decreases? Why?
- TOS decreases; given a specific rotation picture, it takes less lift to get a lighter aircraft airborne. Since AOA is set by the rotation picture, lift required will be obtained at a lower IAS.
What happens to takeoff distance (TOD) as:
1). temperature and pressure altitude increase? Why?
2). headwind increases? Why?
3). RCR decreases? Why?
4). weight decreases? Why?
1). temperature and pressure altitude increase? Why?
- TOD increases; air density decreases, so thrust and acceleration are reduced. Higher TAS required for takeoff. Less acceleration to reach a higher TOS = longer TOD.
2). headwind increases? Why?
- TOD decreases because TOS achieved at a slower groundspeed.
3). RCR decreases? Why?
- Negligible effect; T-38 tires are maintained at a high pressure, so rolling friction is considered negligible (however, standing water will inhibit acceleration).
4). weight decreases? Why?
- TOD decreases because TOS decreases. Less distance is required to reach the slower TOS.
What happens to SETOS as:
1). temperature and pressure altitude increase? Why?
2). headwind increases? Why?
3). RCR decreases? Why?
4). weight decreases? Why?
5). Why is SETOS + 10 the optimum single-engine rotation speed?
1). temperature and pressure altitude increase? Why?
- SETOS increases; higher density altitude means decreased thrust, so SETOS must be higher to ensure excess thrust is available to climb out of ground effect.
2). headwind increases? Why?
- No change to SETOS; same IAS required, it will just be achieved at a slower groundspeed.
3). RCR decreases? Why?
- No change; RCR does not effect speed required to generate lift for takeoff.
4). weight decreases? Why?
- SETOS decreases; given a specific rotation picture, it takes less lift to get a lighter aircraft airborne. Since AOA is set by the rotation picture, lift required will be obtained at a lower IAS.
5). Why is SETOS + 10 the optimum single-engine rotation speed?
- For each knot above SETOS (up to SETOS + 10), you get an extra 8-50 FPM climb capability (depending on temperature and pressure altitude). Drag from retracting the gear above SETOS + 10 is not considered a factor. Consider the length of runway remaining and tire speed limits in delaying rotation above SETOS.
What happens to decision speed (DS) as:
1). temperature and pressure altitude increase? Why?
2). headwind increases? Why?
3). RCR decreases? Why?
4). weight decreases? Why?
1). temperature and pressure altitude increase? Why?
- DS increases; thrust and acceleration are reduced due to lower air density, so in order to reach SETOS (which has increased) by the end of runway, you need to accelerate on two engines longer, so DS must increase.
2). headwind increases? Why?
- DS decreases; SETOS attained at a lower groundspeed, so it’s easier to reach SETOS by the end of runway, and you can lose an engine earlier.
3). RCR decreases? Why?
- No change to DS; DS only concerned with takeoff and RCR effects on takeoff are considered negligible.
4). weight decreases? Why?
- DS decreases; SETOS is lower and acceleration is better, so you can lose an engine at a lower airspeed and still reach SETOS by the end of the runway.
What happens to refusal speed (RS) as:
1). temperature and pressure altitude increase? Why?
2). headwind increases? Why?
3). RCR decreases? Why?
4). weight decreases? Why?
1). temperature and pressure altitude increase? Why?
- RS decreases; reduced air density means thrust and acceleration are reduced, so it takes more distance to reach a given airspeed. Therefore, abort must be started at a lower speed speed in order to stop by the end of the runway.
2). headwind increases? Why?
- RS increases; for a given IAS, groundspeed is slower. Since stopping is related to groundspeed, you can accelerate to a higher IAS and still stop.
3). RCR decreases? Why?
- RS decreases; lower RCR means reduced braking effectiveness and increased stopping distance, so you must initiate an abort at a lower speed to stop in the remaining runway.
4). weight decreases? Why?
- RS increases; a lighter plane has less momentum and is easier to stop, so you can accelerate to a higher speed and still have room to stop.
What happens to Critical Engine Failure Speed (CEFS) as:
1). temperature and pressure altitude increase? Why?
2). headwind increases? Why?
3). RCR decreases? Why?
4). weight decreases? Why?
1). temperature and pressure altitude increase? Why?
- CEFS increases; CEFS involves stopping and going, so we need to figure out which is affected more. Lower air density decreases takeoff acceleration (less thrust) and increases takeoff groundspeed. Stopping distance is only increased because of the higher takeoff groundspeed. Takeoff acceleration suffers more than stopping distance, so to keep takeoff distance and stopping distance equal, CEFS must increase.
2). headwind increases? Why?
- CEFS increases; stopping distance is greatly reduced due to lower groundspeeds, so to keep stopping distance and takeoff distance equal, CEFS must increase.
3). RCR decreases? Why?
- CEFS decreases; stopping distance is greatly increased due to reduced braking effectiveness. Since stopping distance is greater than takeoff distance, CEFS must be decreased to keep stopping and takeoff distance equal.
4). weight decreases? Why?
- CEFS decreases; takeoff distance is reduced because of better 2-engine acceleration, better single engine acceleration after CEFS, and a lower SETOS. Stopping distance isn’t reduced as much as takeoff distance is reduced, so CEFS must decrease to keep stopping distance and takeoff distance equal.
