1. Introduction to Minimum Requirements for Electric Propulsion
3. Requirements and Ratings in ASTM F3338
4. Endurance and Durability Testing in ASTM F3338-24
Introduction to Minimum Requirements for Electric Propulsion
- Q1: Why does ASTM F3338-24 not cover all possible engine configurations?
- Because it is meant to be used alongside other supporting documents
- Because most configurations are not airworthy
- Because the FAA doesn’t permit electric hybrid designs
- Q2: What is the role of the FAA in electric engine design approval in the U.S.?
- It handles only post-certification inspections
- It serves as the civil aviation authority and issues design guidance
- It certifies only imported electric aircraft
- Q3: What advantage does electric propulsion offer, as described in the video?
- Reduced noise and no exhaust emissions
- Faster takeoff speeds
- Increased turbulence resistance
- Q4: Which of the following is not one of the potential uses for electric aircraft mentioned in the video?
- Air ambulance
- Cargo delivery
- Military combat operations
- Q5: What is significant about Pipistrel’s Vellis Electro?
- It is a hybrid engine aircraft certified for IFR
- It was the first FAA-certified electric drone
- It is the first type-certificated electric aircraft for pilot training
- Q6: What did the FAA grant in March 2024 regarding electric aircraft?
- An LSA airworthiness exemption for flight training
- A full type certificate for air taxis
- An overhaul inspection waiver for electric motors
- Q7: Why are FAA “special conditions” being created for some electric engines?
- To replace existing standards entirely
- Because no standard certification yet exists for all electric engines
- To relax safety requirements temporarily
- Q8: How did the FAA establish the “special conditions” for certifying electric engines?
- Based on international UN aviation goals
- By combining Part 33 standards with F338-18 technical criteria
- By exempting electric aircraft from existing rules
- Q9: What milestone did Joby Aviation achieve in 2022?
- They received their FAA Part 135 air carrier certificate
- They flew across the Atlantic using electric propulsion
- They were acquired by the Air Force
- Q10: As of 2025, what is one ongoing challenge for electric engine certification in the U.S.?
- Limited funding from private companies
- Incompatibility with U.S. airspace systems
- Absence of comprehensive certification requirements for all electric engines
Terminology in ASTM F3338
- Q1: Why is a common understanding of terminology important in aviation, according to the video?
- It fosters teamwork and avoids confusion
- It simplifies engine manufacturing
- It allows for faster aircraft certification
- Q2: How does the video define the role of an electric engine in aircraft?
- It controls electronic signals from the cockpit
- It converts electric power into mechanical thrust for propulsion
- It manages the flight computer interface
- Q3: What is the main difference between an electric engine and a motor, as explained in the video?
- A motor requires fuel; an engine doesn’t
- A motor produces rotational power; an engine provides aircraft propulsion
- An engine is smaller than a motor
- Q4: What does “rated maximum continuous power” refer to in ASTM F3338?
- Power used only during descent
- Maximum power for 5 minutes
- Brake power available for unrestricted use
- Q5: How long can “rated takeoff power” be used, as defined in the video?
- No more than five minutes
- Indefinitely during ascent
- Up to 10 minutes in emergencies
- Q6: Which of the following is an example of non-periodic duty in aircraft systems?
- Landing gear retraction
- Constant-speed propeller adjusting pitch during flight
- Ice sensor monitoring
- Q7: What characterizes periodic duty in aviation systems?
- Random load variations throughout flight
- Load spikes during power loss
- One or more constant loads for specific durations
- Q8: What’s the function of deicing boots as discussed in the context of duty types?
- Non-periodic load balancing
- Example of periodic duty due to fixed operating cycle
- Heat dissipation management
- Q9: Which term best describes how the load behaves across operating ranges in periodic duty?
- Constant for defined durations
- Unpredictable and fluctuating
- Constant with varied time
- Q10: How does ASTM F3338 reference external standards?
- Only when no internal definitions exist
- It avoids external references altogether
- It calls out other standards like SAE J245 when needed
Requirements and Ratings in ASTM F3338
- Q1: What kind of information must be included for safe engine operation?
- Things like maximum torque, temperature, and vibration limits
- Marketing data and manufacturer logos
- A list of all suppliers used during design
- Q2: What factors influence how long and how hard an electric engine can run safely?
- Paint finish and wing length
- Duty cycle involving power, speed, torque, and time
- Whether the aircraft is single- or twin-propeller
- Q3: How does the video say power ratings can be visually represented?
- Through barcodes scanned into software
- Using time-sequenced graphs or pre-defined duty profiles
- Through temperature gauges on control panels
- Q4: What real-world example does the video use when discussing “overspeed”?
- The rotor must not break apart even if spinning faster than normal
- When the engine stalls mid-air
- Pilots manually throttle up during storms
- Q5: What kind of electric engine parts need to be taken out after a certain number of hours or flights?
- Any parts exposed to wind
- All cockpit controls
- Lifelimited parts like bearings with low-cycle fatigue
- Q6: Which part is mentioned as critical, but not necessarily lifelimited, in electric engines?
- The propeller
- The landing gear
- The wing flaps
- Q7: What does the safety analysis process aim to do in electric engine design?
- Ensure proper color coding on wiring
- Identify what could go wrong and reduce hazard risks
- Determine battery recharge speed
- Q8: What kind of events can block cooling systems in electric aircraft?
- Dust storms and overheating
- Cabin pressurization errors
- Bird strikes, hail, or ice
- Q9: What must happen if there’s structural damage to a cooling system?
- A restart sequence must be triggered
- A flight delay must be reported
- It should not lead to any hazardous engine behavior
- Q10: What is the takeaway message about engine safety and design?
- That these engines are safer because they’re smaller
- That safety must be ensured in real conditions like failure and ingestion
- That engines are mostly hands-off for pilots now
Endurance and Durability Testing in ASTM F3338-24
- Q1: What is the primary goal of endurance and durability testing for electric engines?
- To ensure no unsafe condition develops during the engine's life or between overhauls
- To increase battery cycle efficiency
- To validate exterior aerodynamic features
- Q2: What does vibration testing aim to confirm?
- That the propeller blade angles stay fixed
- That any vibration encountered is within acceptable limits
- That the aircraft structure does not flex
- Q3: What must be proven during the over torque test?
- That the engine can keep running without maintenance at over torque levels
- That torque sensors are replaced post-test
- That the engine fuel system is optimized
- Q4: What is a key requirement of the over temperature test?
- Continuous operation for at least 6 hours
- Rotor magnets must exceed their thermal rating
- Operation until steady-state plus one hour, with magnets within limits
- Q5: What is the main purpose of calibration tests?
- To align the engine’s GPS unit
- To establish power characteristics across operational ranges
- To ensure the weight-to-thrust ratio meets baseline specs
- Q6: What types of functions are included in operation testing?
- Landing gear extension, retraction, and braking
- Throttle smoothing and taxiing
- Powering on, idling, accelerating, and overspeeding
- Q7: What does the power response test assess?
- Flight time per battery cycle
- The engine's ability to increase from minimum to peak power without damage
- Noise levels at different altitudes
- Q8: When are rotor locking tests performed?
- Only on hybrid-electric engines
- If the engine has a rotor-locking feature that must be tested under torque
- At cruising speed with autopilot engaged
- Q9: What happens during the teardown inspection?
- The engine is fully disassembled and inspected post-testing
- The batteries are swapped and discarded
- The cooling system is flushed and re-oiled
- Q10: What is the focus of containment testing?
- Evaluating wiring insulation under pressure
- Verifying propeller pitch memory
- Assessing energy and path of any fragments from rotating component failures