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ASN Wikibase Occurrence # 15834
Last updated: 2 June 2020
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Date:02-AUG-1999
Time:13:26
Type:Silhouette image of generic PA23 model; specific model in this crash may look slightly different
Piper PA-23-160 Apache
Owner/operator:Caernarfon Aircraft Maintenance Co. Ltd.
Registration: G-ARTD
C/n / msn: 23-1530
Fatalities:Fatalities: 1 / Occupants: 1
Other fatalities:0
Aircraft damage: Written off (damaged beyond repair)
Category:Accident
Location:Moel Hebog, Snowdonia, North Wales -   United Kingdom
Phase: En route
Nature:Test
Departure airport:Caernarfon Airport (EGCK)
Destination airport:Caernarfon Airport (EGCK)
Investigating agency: AAIB
Narrative:
Written off (destroyed) 2-8-1999 due to a CFIT (Controlled Flight Into Terrain) when flew into the 2,569 feet peak of Moel Hebog, Snowdonia, North Wales, at 1,850 feet amsl, during a test flight from Caernafon Airport. The pilot (the sole person on board) was killed. According to the following extract from the official AAIB report into the accident:

"The main purpose of the flight was thought to be to an airborne test of the function of the right engine starter motor, which had been refitted after repair. The precise time of departure from Runway 26 at Caernarfon Airport was not determined, however, it was the usual practice to call Royal Air Force (RAF) Valley Air Traffic Control shortly after take off. Such a transmission was recorded by RAF Valley ATC between 13:14:50 hours and 13:15:36 hours, a transcription of which is reproduced, in part, below:

Aircraft: --- TWINAPACHE JUST AIRBORNE OUT OF CAERNARFON SQUAWKING 7000 IN THE CLIMB TO THE LLEYNPENINSULA AREA FOR AIRTEST REQUESTING FIS
ATC: --- FIS THE HOLYHEAD 1007 SAY AGAIN HEIGHT
Aircraft: 1007 CLIMBING TO 4000 FEET WILL BE OPERATING IN THE BLOCK 4000 TO 2000 FEET"

No further radio communication were reported between the aircraft and any ground station. Radar data, recorded from both St Annes and Clee Hill Radars, was used to determine the aircraft's flight path. The first contact was at 13:16:33 hours, 1.4 nautical miles north-west of the airfield; the aircraft's altitude was about 1,540 feet amsl.

Subsequent contacts indicated that the aircraft was turning right and climbing. It passed the eastern edge of the airport, tracked south-east and had climbed to about 4,840 feet amsl by 13:21:30 hours. Almost immediately, it started to descend and when, at 13:24:01 hours, it was 2.3 nautical miles to the south-west of Moel Hebog, it started a left turn to track northerly towards the mountain.

During the turn, the average rate of descent was about 2,400 feet per minute and the ground speed was about 165 to 170 knots. Radar contact was lost at 13:25:10 hours, when the aircraft was 1.7 nautical miles south of Moel Hebog, at 3,040 feet amsl.

The lack of radar contact, below 1,500 feet amsl shortly after take off, and below 3,000 feet amsl just prior to the accident, was attributed to the intervening high ground between the aircraft and the radar heads.

Witnesses at the eastern end of Llyn Cwmystradllyn, the lake at the foot of Moel Hebog, saw the aircraft fly over them, in straight and level flight, into the side of the mountain. The engine sounded normal and there was no change in the engine noise up to the point of impact. One of these witnesses then went to a house at the other end of the lake, about 0.7 nautical miles away, and telephoned the emergency services. The police logged this call at 13:48:15 hours."

Damage sustained to airframe: Per the AAIB report "aircraft destroyed". as a result, the registration G-ARTD was cancelled by the CAA on 19-11-1999 as "destroyed".

Sources:

1. AAIB: https://assets.publishing.service.gov.uk/media/5422fff740f0b61346000ae1/dft_avsafety_pdf_501267.pdf
2. CAA: https://siteapps.caa.co.uk/g-info/rk=ARTD
3. https://abpic.co.uk/pictures/view/1065235_
4. https://en.wikipedia.org/wiki/Moel_Hebog
5. http://news.bbc.co.uk/2/hi/uk_news/wales/727775.stm
6. https://www.planepictures.net/v3/show_en.php?id=8016

Accident investigation:
cover
  
Investigating agency: AAIB
Status: Investigation completed
Duration:
Download report: Final report


Revision history:

Date/timeContributorUpdates
14-Mar-2008 23:03 Bleiente Added
17-Oct-2009 00:16 andrewaircraft Updated
04-Aug-2012 17:28 Dr. John Smith Updated [Source]
25-May-2013 01:52 Dr. John Smith Updated [Source, Embed code]
04-Jul-2016 20:03 Dr.John Smith Updated [Time, Departure airport, Destination airport, Source, Narrative]

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