June Daily Questions

June Daily Questions

Aerodynamics: Reference TC 3-04.4

1. Rotational relative wind modified by induced flow (at a hover, as well as airspeed during directional flight) is known as: Resultant Relative Wind

Figure 1-8

2. You pick up the aircraft to conduct a hover power check. Your predicted hover power torque is 60%. You have a 23kt headwind. Your actual hover power torque is 53%. If all other factors remain the same, what aerodynamic factor is causing the decrease in power required?

Effective Translational Lift. ETL is an increase in efficiency of the rotor system as the helicopter begins to work in relatively undisturbed air (usually by "out-running" it's vortexes). It occurs at about 16-24 knots. Even though we usually think about ETL occurring because we gain airspeed until 16-24 knots, aerodynamically a wind of the same amount has the same effect on the helicopter.

3. I am in a single rotor helicopter traveling at a high rate of speed. I apply rapid left cyclic to avoid a bird. What should I be concerned with in regards to torque? Rotor? What is the name of this aerodynamic factor?

Torque will increase. NR will decrease (Transient Droop Improvement and the additional NR sensor will prevent a considerable decrease in NR; however, if the amount of transient TQ exceeds power available, you will droop the rotor.)

Transient torque is a phenomenon occurring in single-rotor helicopters when lateral cyclic is applied and is caused by aerodynamic forces. For conventional American helicopters where the main rotor turns counterclockwise, a left cyclic input causes a temporary rise in torque and a right cyclic input causes a temporary drop in torque. This is due to the increased AoA over the rear half of the aircraft leading to an increase in induced drag.

4. I am hovering at 100ft AGL. What are my appropriate common standards in regard to altitude?

Reference: UH60 dATM

(a) Maintain heading ±10 degrees.
(b) Maintain altitude, ±3 feet (±5 feet for OGE). *
(c) Do not allow drift to exceed 3 feet (10 feet for OGE hover). *
(d) Maintain ground track within 3 feet.
(e) Maintain a constant rate of movement appropriate for existing conditions.

5. I am hovering at 100ft AGL with 78% Hover Power Torque applied. I experience a single engine failure (that sucks). How much % Torque would I need to reduce in order to remain below my max torque available?

In a single engine condition, your hover torque will double to 156%. In order to remain within your max torque available (single engine), you would have to reduce the torque by 46% to achieve below 110%.

6. I am hovering at Sea Level, 100ft AGL, and experience a single engine failure. My UH60M weighs 19,000 and winds are calm. At 100ft AGL, according to the UH60 Operators manual, will I be able to achieve single engine flyaway airspeed prior to impacting the ground? Reference?

No. Check the Height Velocity Avoid Region Figure 9-2, Page 9-9. This should be discussed with your crew prior to conducting hoist or other OGE hover tasks. Hovering into the wind will assist in achieving single engine fly-away airspeed.

7. What is the minimum weather required to file VFR to a Class D destination IAW with AR95-1? (Assuming the airfield has no specific weather minimums published.)

½ mile & Clear of Clouds (SVFR)
Par. 5-2c. (4) ..Aviators may file flight plans to a destination within Class B, C, D, and E Surface when weather conditions are known to be equal or greater than known SVFR minima for that airspace ETA through one hour after ETA. Helicopter SVFR is ½ mile, clear of clouds unless a higher minimum is required at that airfield.

8. You are on a VFR flight plan and fins yourself over a layer of clouds. Assuming all installed equipment is operational. How long can you fly VFR over the top?

No time limit.
Par. 5-4b. Over-the-top flights. Aircraft will not be flown above a cloud or fog layer under VFR for more than 30 minutes unless—
(1) The aircraft is equipped for IMC flight and not restricted from IMC flight.
(2) All IFR and requirements can be met for the remaining flight.

9. If a simulator period is “flown” prior to the actual aircraft in the same duty day; do the flight hours in the sim count towards the maximum amount of hours that can be flown in a day?

Army Aviation SOP

10. You are running up the aircraft and notice its 35 degrees C. How long can you run the backup pump, assuming the rotor is static?

UH60-10 Ch. 5-31.
For temps 33-38C, you can operate the backup pump for 24 minutes before requiring a 72 minute cooldown.

11. Which of the following maneuvers are authorized when a pilot is “cleared for the option?”

Aeronautical Information Manual: Pilot/Controller Glossary-
ATC authorizes for an aircraft to make a touch-and-go, low approach, missed approach, stop and go, or full stop landing at the discretion of the pilot

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