Slush - 1/2 inch rule
 

Incident

In US a domestic incident in April 1959 started official concern and regulatory action. A heavily loaded Boeing 707 transport New York departing from New York International Airport, Idlewild, on a transcontinental flight had cleared a fence by approximately 1.5 meter. Inspection after the flight revealed considerable slush damage to the aircraft. It was reported to have been approximately 1.5 inch of slush on the runway.

No slush rule

Through a FAA Circular Memorandum, takeoff from a surface with any measurable amount of slush was prohibited. Boeing investigated the issue (Report on effect of slush on Ground Run Distance, Boeing Document No. D6-5198, January 1959), and together with research by NASA, indication was that the “no slush rule” was unnecessarily restrictive and needed revision.

Half inch rule

Less than one year from the incident FAA established the 0.5 inch rule (Federal Aviation Operational Division Memorandum 60-7, March 1960). This rule is still to be found in the FAA Advisory Circular of today. (FAA, AC No 91-6A, 24 May 1978)


Question:

Can anyone give me more information on the April 1959 incident with the Boeing 707 flight?

(I believe it was an American Airline)

From UK AIC No. 80/1962 we find this table:

Calculated Effect on Take-off Performance of a Uniform Layer of Slush or Water on a Runway

Aircraft type and % Increment to the Take-off Field Length required for a Depth of Slush or Water of 0.5" (15 mm).

Boeing 707-436 20
Comet 4 20
Ambassador 50
Argonaut 45
Britannia 30
Constellation 35
DC-3

(Fingertrouble - I try again)

From UK AIC No. 80/1962 we find this table:

Calculated Effect on Take-off Performance of a Uniform Layer of Slush or Water on a Runway

Aircraft type, and % Increment to the Take-off Field Length required for a Depth of Slush or Water of 0.5\" (15 mm).

Boeing 707-436, 20
Comet 4, 20
Ambassador, 50
Argonaut, 45
Britannia, 30
Constellation, 35
DC-3, 20
DC-4, 45
DC-6, 30
DC-7C, 30
Bristol 170 (Freighter), 20
Hermes, 45
President, 30
Prince, 30
Viscount, 50
Vanguard, 20
Viking, 20

Note.-
These figures are based on the assumption that, for nose-wheel aircraft, the nose-wheel is kept in contact with the runway until the aircraft is rotated. Smaller increments than the above may be justified in special circumstances.