14 CFR Appendix B to Part 33, Certification Standard Atmospheric Concentrations of Rain and Hail

Status message

There is 1 Update appearing in the Federal Register for 14 CFR Part 33. View below or at eCFR (GPOAccess)
prev | next
Appendix B to Part 33 - Certification Standard Atmospheric Concentrations of Rain and Hail

Figure B1, Table B1, Table B2, Table B3, and Table B4 specify the atmospheric concentrations and size distributions of rain and hail for establishing certification, in accordance with the requirements of § 33.78(a)(2). In conducting tests, normally by spraying liquid water to simulate rain conditions and by delivering hail fabricated from ice to simulate hail conditions, the use of water droplets and hail having shapes, sizes and distributions of sizes other than those defined in this appendix B, or the use of a single size or shape for each water droplet or hail, can be accepted, provided that applicant shows that the substitution does not reduce the severity of the test.

Table B1 - Certification Standard Atmospheric Rain Concentrations

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.

Table B2 - Certification Standard Atmospheric Hail Concentrations

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.

Note: Source of data - Results of the Aerospace Industries Association (AIA Propulsion Committee (PC) Study, Project PC 338-1, June 1990.

Table B3 - Certification Standard Atmospheric Rain Droplet Size Distribution

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.

Table B4 - Certification Standard Atmospheric Hail Size Distribution

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.

[Doc. No. 28652, 63 FR 14799, Mar. 26, 1998]

This is a list of United States Code sections, Statutes at Large, Public Laws, and Presidential Documents, which provide rulemaking authority for this CFR Part.

This list is taken from the Parallel Table of Authorities and Rules provided by GPO [Government Printing Office].

It is not guaranteed to be accurate or up-to-date, though we do refresh the database weekly. More limitations on accuracy are described at the GPO site.


United States Code

Title 14 published on 2015-11-17

The following are ALL rules, proposed rules, and notices (chronologically) published in the Federal Register relating to 14 CFR Part 33 after this date.

  • 2015-11-20; vol. 80 # 224 - Friday, November 20, 2015
    1. 80 FR 72561 - Special Conditions: CFM International, LEAP-1B Engine Models; Incorporation of Woven Composite Fan Blades
      GPO FDSys XML | Text
      DEPARTMENT OF TRANSPORTATION, Federal Aviation Administration
      Final special conditions; request for comments.
      The effective date of these special conditions is December 21, 2015. We must receive your comments by December 7, 2015.
      14 CFR Parts 33 and 35

Title 14 published on 2015-11-17.

The following are only the Rules published in the Federal Register after the published date of Title 14.

For a complete list of all Rules, Proposed Rules, and Notices view the Rulemaking tab.

  • 2015-11-20; vol. 80 # 224 - Friday, November 20, 2015
    1. 80 FR 72561 - Special Conditions: CFM International, LEAP-1B Engine Models; Incorporation of Woven Composite Fan Blades
      GPO FDSys: XML | Text
      DEPARTMENT OF TRANSPORTATION, Federal Aviation Administration
      Final special conditions; request for comments.
      The effective date of these special conditions is December 21, 2015. We must receive your comments by December 7, 2015.
      14 CFR Parts 33 and 35