A grass runway was constructed in 1927 by Cecil Levien with the assistance of native labourers. The first landing at Wau was made on 19 April 1927 by Ernest Mustar in a De Havilland DH.37 owned by Guinea Gold Airways from Lae Airfield. The airfield was extended during the Second World War to 1500 x 100 x 4000 yards as described in 1942. Wau airfield was a rough Kunai grass airstrip in length with a 12% slope heading directly for Mount Kaindi. Aircraft could approach from the northeast only, landing uphill and taking off downhill. The mountain at the end of the runway prevented second attempts at landing and precluded extension of the strip. Pilots had to manoeuvre Dakotas under clouds and through dangerous passes, dodging a peak here and cloud there, landing at high speeds. This required good visibility, but the weather over Owen Stanley Range was characterised by frequent storms, down drafts, and mists which rose from the jungle floor.