Some history from ICAO STUDY GROUP ON SNOW, SLUSH, ICE AND WATER ON AERODROMES
Memorandum No. 29, 14 August 1972 and No. 32, 17 April 1973, Attachment
Permissible snow bank height
(IATA representative)
1. One of our member Airlines has just drawn our attention to a problem of ice ingestion which resulted in extensive damage to the outer engine of a B-747 aircraft. It has been suggested that this incident was the result of inadequate clearance of snow from the areas adjacent to the edge of the runway concerned.
2. As you are aware the 6th EUM/RAN meeting recently developed guidance material on snow clearance profiles along the edges of runway, having in mind the extensive overhang of the outer engine pods of B-747 and similar types of aircraft.
3. The incident mentioned above did not occur in Europe and unfortunately the Authorities concerned did not appear to recognize or be sympathetic to the problem. For this reason it has been suggested that the development of guidance material on this aspect of snow clearance be placed on the work programme of the ICAO Study Group on Snow, Slush etc and I hope, therefore, that it is not too late to include it”
The incident:
KLM – B-747 – Captains story. (By TELEX)
Snow Clearance JFK. KL (number) Arrival feb 21 recived ATIS
Runway ploughed and swept.
Observed conditions 22L/22R showed clearance extended to elevated R/W lights only. At and beyond lights residual patches frozen snow one to two inches thick existed. These clearly lifted and ingested by outer engines during normal reversing. Following summarizes content discussions with (Name) and ITZ KLM. (Name) clearance policy directed at 150 ft cleared width in accordance ATA requirements. This coincides R/W light placement all JFK runways. Hard shoulder width 31R ample to accommodate machinery for additional clearance but other runways could be marginal this purpose. (Name) currently unable to commit to shoulder clearance since neither ATA or other 747 operators input indicates need thereof. Hard shoulder erosion problems from 747 operations are admitted and this CMA together with visual observations recorded above CMA were thus used as arguments in stressing need for review current policy. Note also Bermuda closure 747 operations due shoulder erosions. (Name) indicated sympathy our standpoint but cannot concede isolated incident of unproven origin is demanding of immediate remedial action. They promise early review with ATA this subject stimulated by current FAA interest.
The following report was obtained from the manufacturer: (TELEX)
Laboratory investigations revealed one fan blade had fractured transversely through the aerofoil between the part.span supports. Broken surface was characteristic of rapid tensile fracture and showed no evidence of fatigue. Leading edge was curled back in opposite direction of rotations. Damage caused by foreign object. Dissembly did not find or reveal evidence permitting identification of the foreign object. Incident could be related to (identification) 747 number four engine ingesting ice during landing on same runway 30 minutes prior to KLM.
The outcome
ICAO guidance material, with profiles, can be found in the ICAO Airport Service Manual, Part 2, Pavement Surface Conditions. ICAO Doc 9137-AN/898.