"The maximum icing conditions in which ice-prevention equipment will be expected to provide adequate protection"

from "FLIGHT INVESTIGATION OF METEOROLOGICAL FACTORS CONDUCIVE TO AIRCRAFT ICING", William Lewis, NACA Conference on Aircraft Ice Prevention A Compilation of Papers Presented by NACA Staff Members. 6505/NACA-1947/8, 1947.

Summary

Early Ice Protection Systems were designed without detailed knowledge of icing conditions in clouds. While successful designs were accomplished with extensive iteration and flight test, more optimal design is only possible if the conditions are known beforehand.

Discussion

Progress ... has been handicapped by the lack of sufficient data on the meteorological factors.
NACA-TN-1855, 1949.

A better understanding of the icing atmosphere evolved in parallel with improved Meteorological Instruments in the years 1944 to 1952. Two of the authors (Kline, Lewis) were meteorologists from the US Weather Bureau. This helped put the data on a sound scientific basis.

Reviews in this thread:

• Meteorology of Icing Clouds

  • Lewis, William: Icing Properties of Noncyclonic Winter Stratus Clouds. NACA-TN-1391, 1947.
    > review : NACA-TN-1391
  • Lewis, William: A Flight Investigation of the Meteorological Conditions Conducive to the Formation of Ice on Airplanes. NACA-TN-1393, 1947.
    > review : NACA-TN-1393
  • Lewis, William, Kline, Dwight B., and Steinmetz, Charles P.: A Further Investigation of the Meteorological Conditions Conducive to Aircraft Icing. NACA-TN-1424, 1947.
    > review : NACA-TN-1424
  • Kline, Dwight B.: Investigation of Meteorological Conditions Associated with Aircraft Icing in Layer-Type Clouds for 1947-48 Winter. NACA-TN-1793, 1949.
    > review : NACA-TN-1793
  • Jones, Alun R., and Lewis, William: Recommended Values of Meteorological Factors to be Considered in the Design of Aircraft Ice-Prevention Equipment. NACA-TN-1855, 1949.
    > review : NACA-TN-1855
  • Lewis, William, and Hoecker, Walter H., Jr.: Observations of Icing Conditions Encountered in Flight During 1948. NACA-TN-1904, 1949.
    > review : NACA-TN-1904
  • Kline, Dwight B., and Walker, Joseph A.: Meteorological Analysis of Icing Conditions Encountered in Low-Altitude Stratiform Clouds. NACA-TN-2306, 1951.
    > review : NACA-TN-2306
  • Hacker, Paul T., and Dorsch, Robert G.: A Summary of Meteorological Conditions Associated with Aircraft Icing and a Proposed Method of Selecting Design Criterions for Ice-Protection Equipment. NACA-TN-2569, 1951.
    > review : NACA-TN-2569
  • Lewis, William, and Bergrun, Norman R.: A Probability Analysis of the Meteorological Factors Conducive to Aircraft Icing in the United States. NACA-TN-2738, 1952.
    > review : NACA-TN-2738
  • Conclusions of the Meteorology of Icing Clouds Thread
    > review : Conclusions of the Meteorology of Icing Clouds Thread

Several publications by Porter Perkins were included in
The Historical Selected Bibliography of NACA-NASA Icing Publications in the "Meteorology of Icing Clouds" section. While the publications are important and useful, they did not directly affect the icing design values adopted in regulations. I will review those in their own thread, to be published at a later date. Perkins was quite productive during his career at NACA and NASA.

• Porter Perkins

  • Perkins, Porter J., and Kline, Dwight B.: Analysis of Meteorological Data Obtained During Flight in a Supercooled Stratiform Clouds of High Liquid-Water Content. NACA-RM-E51D18, 1951.
  • Perkins, Porter J.: Preliminary Survey of Icing Conditions Measured During Routine Transcontinental Airline Operation. NACA-RM-E52J06, 1952.
  • Perkins, Porter J.: Statistical Survey of Icing Data Measured on Scheduled Airline Flights over the United States and Canada from November 1951 to June 1952. NACA-RM-E55F28a, 1955.
  • Perkins, Porter J., Lewis, William, and Mulholland, Donald R.: Statistical Study of Aircraft Icing Probabilities at the 700- and 500- Millibar Levels over Ocean Areas in the Northern Hemisphere. NACA-TN-3984, 1957.
  • Perkins, Porter J.: Icing Frequencies Experienced During Climb and Descent by Fighter-Interceptor Aircraft. NACA-TN-4314, 1958.
  • Perkins, Porter J.: Summary of Statistical Icing Cloud Data Measured Over United States and North Atlantic, Pacific, and Arctic Ocean During Routine Aircraft Operations. NASA Memo 1-19-59E, 1959. archive.org
  • Aircraft icing problems - After 50 years