Simon Glancey has submitted the following:

Sgt. Appleby was the Wireless Operator aboard Handley Page Hampden I AE393 EQ-G of 408 (R.C.A.F.) Squadron, which crashed at Howgill Scar in Teesdale, returning from a mission to Hamburg.

The Hampden became lost in bad weather after wireless failure meant they could not gain a positional fix from the UK. Believing they were much further south, the Hampden descended through snow clouds, and struck high ground, killing three of the four crew. The pilot, S/L W. J. Burnett, D.F.C., R.C.A.F., was the only survivor.
The Best Of Lives: Air Commodore Wilf Burnett; AuthorHouse, 2010; ISBN 978-1452064819, pages 87-93

John Jones has enlarged on the story of the crash:

408 Squadron Hampden I AE393 EQ-G took off from RAF Balderton at 17:15 for Hamburg

Homeward bound, the crew became lost upon crossing the English coast, and while they heard the warning tones that barrage balloons were near them, they could not pin point their position. It is possible that these barrage balloons were in the Middlesbrough area and the aircraft had crossed the coastline somewhere over the River Tees estuary.

The weather was poor on this night, and a number of other crews were struggling to make safe landings. One of the wireless operators requested assistance from a direction finding station at just before midnight, but other aircraft requested higher priority direction fixes, so this aircraft was deemed lesser priority, and when help was requested a second time no reply came.

The events of what then happened is not known, but whilst flying in cloud, the aircraft flew into the side of Bishopdale (a spur of Wensleydale) at Dalefoot, West Burton, 13 miles South West of Catterick, North Yorkshire, at around 00:30 (police records) or 03:00 (RAF records) into deep snow. Two of the crew were thrown out of the aircraft into the snow and were killed, two others were trapped in the cockpit area, and were rescued by a number of farmers who were alerted of the crash, and made their way up to the site. Sadly, one of these trapped airmen died soon after being rescued.

The pilot survived, and was initially treated for his injuries at a nearby farm, before being taken to Catterick Military Hospital. The pilot could not remember anything about the crash, he reported the altimeter had read at 5,000 feet prior to the impact with a hillside near West Burton, and an investigation concluded that the altimeter was probably reading incorrectly at the time of the crash. (Aviation Safety Network)

Crew
Pilot: J/40076 Squadron Leader Wilfred Jasper Burnett DFC RCAF - Injured.
Navigator: 580636 Flt Sgt James Arthur Bunting - Otley (Newall with Clifton & Lindley) Cemetery Section I Grave 211.
Wireless Operator/Air Gunner: 995056 Sgt John Robinson Appleby - Stockton on Tees (Durham Road) Cemetery Section G2 Non-Conformist Row G Grave 35.
Wireless Operator/Air Gunner: 619483 Sgt Maurice Jones - Tibshelf (St John the Baptist) Churchyard.

John Robinson Appleby is remembered in Billingham on B139.01 and B139.09 and in a RAF Roll of Honour

Yorkshire Aircraft telling of the incident
The CWGC entry for Sergeant Appleby