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Condition | Total air temperature | Supercooled water concentrations (minimum) | Median volume drop diameter | Duration |
---|---|---|---|---|
1. Glaze ice conditions | 21 to 25 °F (−6 to −4 °C) | 2 g/m 3 | 25 to 35 microns | (a) 10-minutes for power below sustainable level flight (idle descent). |
(b) Must show repetitive, stabilized operation for higher powers (50%, 75%, 100%MC). | ||||
2. Rime ice conditions | −10 to 0 °F (−23 to −18 °C) | 1 g/m 3 | 15 to 25 microns | (a) 10-minutes for power below sustainable level flight (idle descent). |
(b) Must show repetitive, stabilized operation for higher powers (50%, 75%, 100%MC). | ||||
3. Glaze ice holding conditions (Turbojet, turbofan, and turboprop only) | Turbojet and Turbofan, only: 10 to 18 °F (−12 to −8 °C) | Alternating cycle: First 1.7 g/m 3 (1 minute), Then 0.3 g/m 3 (6 minute) | 20 to 30 microns | Must show repetitive, stabilized operation (or 45 minutes max). |
Code of Federal Regulations /
Title 14 - Aeronautics and Space /
Vol. 1 / 2023-01-01716 | ||||
Turboprop, only: 2 to 10 °F (−17 to −12 °C) | ||||
4. Rime ice holding conditions (Turbojet, turbofan, and turboprop only) | Turbojet and Turbofan, only: −10 to 0 °F (−23 to −18 °C) | 0.25 g/m 3 | 20 to 30 microns | Must show repetitive, stabilized operation (or 45 minutes max). |
Turboprop, only: 2 to 10 °F (−17 to −12 °C) |
Condition | Total air temperature | Supercooled water concentrations (minimum) | Mean effective particle diameter | Demonstration |
---|---|---|---|---|
1. Rime ice condition | 0 to 15 °F (−18 to −9 °C) | Liquid—0.3 g/m 3 | 15–25 microns | By engine test. |
2. Glaze ice condition | 20 to 30 °F (−7 to −1 °C) | Liquid—0.3 g/m 3 | 15–25 microns | By engine test. |
3. Snow ice condition | 26 to 32 °F (−3 to 0 °C) | Ice—0.9 g/m 3 | 100 microns (minimum) | By test, analysis or combination of the two. |
4. Large drop glaze ice condition (Turbojet, turbofan, and turboprop only) | 15 to 30 °F (-9 to -1 °C) | Liquid—0.3 g/m 3 | 100 microns (minimum) | By test, analysis or combination of the two. |
Engine Inlet Throat Area (A)—Square-meters (square-inches) | Bird weight kg. (lb.) |
---|---|
1.35 (2,092)>A | 1.85 (4.07) minimum, unless a smaller bird is determined to be a more severe demonstration. |
1.35 (2,092)≤A<3.90 (6,045) | 2.75 (6.05) |
3.90 (6,045)≤A | 3.65 (8.03) |
Engine Inlet Throat Area (A)— Square-meters (square-inches) | Bird quantity | Bird weight kg. (lb.) |
---|---|---|
0.05 (77.5)>A | none | |
0.05 (77.5)≤A <0.10 (155) | 1 | 0.35 (0.77) |
0.10 (155)≤A <0.20 (310) | 1 | 0.45 (0.99) |
0.20 (310)≤A <0.40 (620) | 2 | 0.45 (0.99) |
0.40 (620)≤A <0.60 (930) | 2 | 0.70 (1.54) |
0.60 (930)≤A <1.00 (1,550) | 3 | 0.70 (1.54) |
1.00 (1,550)≤A <1.35 (2,092) | 4 | 0.70 (1.54) |
1.35 (2,092)≤A <1.70 (2,635) | 1 | 1.15 (2.53) |
plus 3 | 0.70 (1.54) | |
1.70 (2,635)≤A <2.10 (3,255) | 1 | 1.15 (2.53) |
plus 4 | 0.70 (1.54) | |
2.10 (3,255)≤A <2.50 (3,875) | 1 | 1.15 (2.53) |
plus 5 | 0.70 (1.54) | |
2.50 (3,875)≤A <3.90 (6045) | 1 | 1.15 (2.53) |
plus 6 | 0.70 (1.54) | |
3.90 (6045)≤A <4.50 (6975) | 3 | 1.15 (2.53) |
4.50 (6975)≤A | 4 | 1.15 (2.53) |
Engine Inlet Throat Area (A)— square-meters (square-inches) | Bird quantity | Bird weight kg. (lb.) |
---|---|---|
1.35 (2,092)>A | none | |
1.35 (2,092)≤A <2.90 (4,495) | 1 | 1.15 (2.53) |
2.90 (4,495)≤A <3.90 (6,045) | 2 | 1.15 (2.53) |
3.90 (6,045)≤A | 1 | 1.15 (2.53) |
plus 6 | 0.70 (1.54) |
Engine inlet throat area (square meters/square inches) | Bird quantity | Bird mass and weight (kg (lbs)) |
---|---|---|
A <2.50 (3875) | none | |
2.50 (3875) ≤A <3.50 (5425) | 1 | 1.85 (4.08) |
3.50 (5425) ≤A <3.90 (6045) | 1 | 2.10 (4.63) |
3.90 (6045) ≤A | 1 | 2.50 (5.51) |
Engine Inlet Hilite area (sq. inch) | Thickness (inch) | Width (inch) | Length (inch) |
---|---|---|---|
0 | 0.25 | 0 | 3.6 |
80 | 0.25 | 6 | 3.6 |
300 | 0.25 | 12 | 3.6 |
700 | 0.25 | 12 | 4.8 |
2800 | 0.35 | 12 | 8.5 |
5000 | 0.43 | 12 | 11.0 |
7000 | 0.50 | 12 | 12.7 |
7900 | 0.50 | 12 | 13.4 |
9500 | 0.50 | 12 | 14.6 |
11300 | 0.50 | 12 | 15.9 |
13300 | 0.50 | 12 | 17.1 |
16500 | 0.5 | 12 | 18.9 |
20000 | 0.5 | 12 | 20.0 |
Altitude (feet) | Rain water content (RWC) (grams water/meter 3 air) |
---|---|
0 | 20.0 |
20,000 | 20.0 |
26,300 | 15.2 |
32,700 | 10.8 |
39,300 | 7.7 |
46,000 | 5.2 |
RWC values at other altitudes may be determined by linear interpolation. | |
Note: Source of data—Results of the Aerospace Industries Association (AIA) Propulsion Committee Study, Project PC 338–1, June 1990. |
Altitude (feet) | Hail water content (HWC) (grams water/meter 3 air) |
---|---|
0 | 6.0 |
7,300 | 8.9 |
8,500 | 9.4 |
10,000 | 9.9 |
12,000 | 10.0 |
15,000 | 10.0 |
16,000 | 8.9 |
17,700 | 7.8 |
19,300 | 6.6 |
21,500 | 5.6 |
24,300 | 4.4 |
29,000 | 3.3 |
46,000 | 0.2 |
HWC values at other altitudes may be determined by linear interpolation. The hail threat below 7,300 feet and above 29,000 feet is based on linearly extrapolated data.
Code of Federal Regulations /
Title 14 - Aeronautics and Space /
Vol. 1 / 2023-01-01741 | |
Note: Source of data—Results of the Aerospace Industries Association (AIA Propulsion Committee (PC) Study, Project PC 338–1, June 1990. |
Rain droplet diameter (mm) | Contribution total RWC (%) |
---|---|
0–0.49 | 0 |
0.50–0.99 | 2.25 |
1.00–1.49 | 8.75 |
1.50–1.99 | 16.25 |
2.00–2.49 | 19.00 |
2.50–2.99 | 17.75 |
3.00–3.49 | 13.50 |
3.50–3.99 | 9.50 |
4.00–4.49 | 6.00 |
4.50–4.99 | 3.00 |
5.00–5.49 | 2.00 |
5.50–5.99 | 1.25 |
6.00–6.49 | 0.50 |
6.50–7.00 | 0.25 |
Total | 100.00 |
Median diameter of rain droplets in 2.66 mm | |
Note: Source of data—Results of the Aerospace Industries Association (AIA Propulsion Committee (PC) Study, Project PC 338–1, June 1990. |
Hail diameter (mm) | Contribution total HWC (%) |
---|---|
0–4.9 | 0 |
5.0–9.9 | 17.00 |
10.0–14.9 | 25.00 |
15.0–19.9 | 22.50 |
20.0–24.9 | 16.00 |
25.0–29.9 | 9.75 |
30.0–34.9 | 4.75 |
35.0–39.9 | 2.50 |
40.0–44.9 | 1.50 |
45.0–49.9 | 0.75 |
50.0–55.0 | 0.25 |
Total | 100.00 |
Median diameter of hail is 16 mm | |
Note: Source of data—Results of the Aerospace Industries Association (AIA Propulsion Committee (PC) Study, Project PC 338–1, June 1990. |
Temperature range—deg C | Horizontal cloud length—nautical miles | LWC— g/m 3 |
---|---|---|
0 to −20 | ≤50 | ≤1.0 |
0 to −20 | Indefinite | ≤0.5 |
< −20 | 0 |