Date:	Thursday 15 November 2018
Time:
Type:	de Havilland Canada DHC-8-402Q Dash 8
Owner/operator:	Flybe
Registration:	G-JECR
MSN:	4139
Year of manufacture:	2006
Engine model:	Pratt & Whitney Canada PW150A
Fatalities:	Fatalities: 0 / Occupants: 39
Aircraft damage:	None
Category:	Serious incident
Location:	Exeter Airport (EXT/EGTE) -   United Kingdom
Phase:	En route
Nature:	Passenger - Scheduled
Departure airport:	Exeter Airport (EXT/EGTE)
Destination airport:	Paris-Charles de Gaulle Airport (CDG/LFPG)
Investigating agency:	AAIB
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
Whilst climbing to FL190 en-route to Paris-Charles de Gaulle Airport, the pilots received an alt mismatch message and they elected to return to Exeter Airport. Following an inspection after landing, a small white crystalline deposit was found covering three of the four static pressure holes on the left primary pitot static probe.

It is probable that the use of a non-approved product, to improve the seal between a test adaptor and the pitot static probe during maintenance immediately prior to this flight, may have resulted in the blockage of the static holes and led to the altitude mismatch message.

The investigation found that a non-approved product was probably used to improve the seal between a testing device and the probe during maintenance immediately before the flight, and this may have resulted in the blockage of the static holes, leading to the altitude mismatch message. Two Safety Recommendations have been made to prevent similar incidents. The maintenance organisation has taken safety action to introduce tighter controls on the test kit equipment.

http://aerossurance.com/safety-management/q400-test-kit-wad-wai/
https://www.gov.uk/government/news/aaib-report-dash-8-q400-serious-incident-and-returned-to-exeter

Other occurrences involving this aircraft

3 February 2016	G-JECR	Flybe	0	En route, between Birmingham and Aberdeen		min
Loss of pressurization
29 August 2016	G-JECR	FlyBe	0	Birmingham International Airport (BHX/EGBB)		min
Tire failure

Dash 8 Q400 altitude and speed mismatch between displays during climb out from Exeterhttps://t.co/We4WXvhPyR pic.twitter.com/UgvEK2GnHV

— AAIB (@aaibgovuk) 31 October 2019

#OTD 2018 #AAIB safety investigation revealed a difference between 'work as imagined' and 'work as done' in testing the pitot static system. http://aerossurance.com/safety-management/q400-test-kit-wad-wai/ #aviationmaintenance #humanfactors #aviationsafety #flightsafety

Date/time	Contributor	Updates
02-Nov-2019 18:54	harro	Added
09-Nov-2019 21:57	Dr. John Smith	Updated [Location, Source, Embed code, Narrative]
06-Dec-2019 21:26	Aerossurance	Updated [Location, Source, Embed code]
13-Dec-2019 20:18	harro	Updated [Source, Accident report, ]
15-Nov-2020 11:14	Aerossurance	Updated [Embed code, Accident report]
24-Dec-2021 17:47	harro	Updated [Accident report]