Ministry of Works in a de Havilland Moth, sharing grapes and throwing the seeds out of the open cockpits. A few months later Prichard was tasked with conducting an aerial survey in Northland. The survey was delayed when the Ministry's Miles Whitney Straight, ZK-AFH, was grounded by bad weather. A supervisor, J. L. Harrison, complained that Prichard was holding back men needed to sow lupin seed. Remembering the grape seeds, Prichard suggested sowing the seed by air. Burying the hatchet, Harrison and Prichard spent that evening experimenting with methods of dispersal, before settling on sewing a sack onto a piece of downpipe. The following morning, 8 March 1939, Prichard flew over Ninety Mile Beach while Harrison, on his signal, held the downpipe out a window and emptied the sack. They then landed and examined the spread of the seeds. It was found a distribution of 1 seed per square foot was obtained from a height of 100 to . On Monday 10 March, they sowed , using 2 lb/acre (224 kg/km2) instead of the 5 lb/acre (560 kg/km2) used when sowing by hand. The pair returned to examine the site at 2 weeks, 1 month and 2 years and at all points the aerially sown land was indistinguishable from that sown by hand. Prichard wrote up the experiment in the NZ Journal of Agriculture (vol 70 p117-120). This came to the attention of the Minister Bob Semple, who Prichard occasionally flew as a VIP. Semple asked how Prichard had obtained permission. Prichard admitted he had not, and had "cribbed" back the time in the ZK-AFH's logbooks by extending the time of other flights. Semple encouraged Prichard to continue, adding "Don't let anyone catch you, and if they do, send them to me". After the outbreak of World War II, he had the good fortune to retain the use of ZK-AFH, when most aircraft were impressed for war service. Prichard conducted various trials between 1939 and 1943, from an early stage adding fertiliser to the seeds, which was found to dramatically improve growth. The success of the fertiliser was such that his trials came to concentrate on this aspect, and its possible application to existing pasture. As a result of Prichard's experiments, in 1945 the Department of Agriculture estimated aerial topdressing would cost about £4 per ton of fertiliser (on a basis of 2 cwt per acre), which was economic (actually,