# Aviologium Full Machine Corpus

## Causal Knowledge Graph Nodes

1. Density Altitude (DA)
- Domain: Weather / Meteorology
- Formula: DA ≈ Pressure Alt + [120 × (OAT - ISA Temp)]
- Impact: Degrades engine combustion, propeller thrust, and wing lift, lengthening ground roll.
- Causal Edges: Causes True Airspeed increase; Exacerbates Ground Roll; Exacerbates Engine Overheating; Exacerbates Continuation Bias.

2. True Airspeed (TAS) & Groundspeed
- Domain: Aerodynamics
- Formula: TAS ≈ IAS × √(ρ₀ / ρ)
- Impact: Increases ~2% per 1,000 ft of altitude above sea level for constant IAS.
- Causal Edges: Manifests as Visual Illusions; Causes Turn Radius expansion.

3. Jet Stream & Clear Air Turbulence (CAT)
- Domain: Meteorology / High Enroute
- Formula: Kelvin-Helmholtz instability occurs when Richardson Number Ri < 0.25.
- Impact: 100-250 kt tailwind boost eastbound; strong vertical wind shear at boundaries.
- Causal Edges: Regulates North Atlantic Tracks; Manifests as Clear Air Turbulence.

4. Hydraulic Power Transfer Unit (PTU)
- Domain: Aircraft Systems
- Function: Bi-directional hydraulic motor-pump transferring pressure between isolated systems without mixing fluids.
- Passenger Acoustic Cue: The rhythmic barking dog noise heard on Airbus A320 series aircraft during single-engine taxi at the gate.

5. Coffin Corner
- Domain: Aerodynamics
- Regime: High-altitude flight envelope where low-speed aerodynamic stall speed converges with high-speed critical Mach limit (Mmo).

6. ETOPS (Extended-range Twin-engine Operations)
- Domain: Regulations
- Standard: Authorizes twin-engine airliners to fly routes up to 180–370 minutes from diversion fields, requiring triple-redundant electrical/hydraulic generation.

7. Stabilized Approach Gate
- Domain: Procedures
- Standard: Mandatory criteria by 1,000 ft IMC / 500 ft VMC (speed +10/-0, configured, sink rate < 1000 fpm). Failure to meet demands immediate go-around.