The Railway Air Services Dakota was ready to depart from Northolt Aerodrome, London, United Kingdom on a scheduled service to Glasgow Airport on behalf of Scottish Airways and had a total of four crew and one passenger on board. The aircraft had been de-iced since it was a cold, snowy evening which had delayed the departure. While the Dakota was waiting the temperature dropped and snow began falling which froze on the wings. The aircraft was finally ready for departure and taxied into position for take-off. The snow storm had closed the airport to incoming traffic and outbound traffic was subject to long delays. The aircraft had been waiting for more than an hour for clearance. When the flight received clearance, the pilot ran the engines up to 45.5 inches of manifold pressure and 2,500 RPM. When the pilot accelerated down the runway he noticed that when the aircraft lifted off, it could not gain any height. The ice on the wings disturbed the air flow, which resulted in the aircraft not gaining any height. It was however too late to abort take-off so the crew was forced to try to get the aircraft to climb. The aircraft flew only a few metres high straight down Angus Drive from the end of the runway until the left wing contacted some rooftops and the aircraft slewed through 90 degrees and came to rest on the roofs of two houses at 44 & 46 Angus Drive in the London suburb of South Ruislip. G-AGZA was severely damaged and radio officer Murdoch was fortunate that he wasn't sitting in his seat as some metalwork was pushed through the seat and it would probably have killed him had he been sitting there. Irene Zigmund and her 4-month old-son David were in the neighbouring house house at the time, but the aircraft came to rest on the roof without even waking the child who was asleep in his cot upstairs. In fact no one was injured in the incident, the crew and passenger all descended into the house's loft, down the loft ladder onto the landing and then down stairs out the front door. The aircraft was a total loss and the house was damaged, but not greatly.
Investigation
It was quickly determined that the cause of the crash was the snow which had frozen to the aircraft's wings while G-AGZA was waiting to take-off, resulting in the aircraft not gaining any height and making an emergency landing on the roof of 46 Angus Drive. The house was subsequently nicknamed "Dakota Rest". The pilot was also assigned a cause factor for failing to abort take-off after noticing it had been snowing and his aircraft being covered in snow. The crash landing on the houses earned the captain the nickname "Rooftop Johnson".
