Date:	Friday 8 January 2016
Time:	22:10
Type:	Boeing 737-86N (WL)
Owner/operator:	Norwegian Airlines
Registration:	EI-FHG
MSN:	37884/3223
Year of manufacture:	2010
Fatalities:	Fatalities: 0 / Occupants: 84
Other fatalities:	0
Aircraft damage:	None
Category:	Serious incident
Location:	near London Gatwick Airport, Horley, Surrey (LGW/EGKK) -   United Kingdom
Phase:	Approach
Nature:	Passenger - Scheduled
Departure airport:	Stockholm-Arlanda Airport (ARN/ESSA)
Destination airport:	London-Gatwick Airport (LGW/EGKK)
Investigating agency:	AAIB
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
AAIB investigation to Boeing 737-86N, EI-FHG: Unreliable airspeed and altitude indications, on approach to London Gatwick Airport, 8 January 2016. The incident was deemed serious enough to warrant an AAIB Investigation, and the following is the summary from the AAIB Report

"The aircraft was on approach to London Gatwick when the crew was presented with erroneous airspeed and altitude information on one of the two cockpit display systems. The crew took appropriate ‘IAS Disagree, ALT Disagree and Airspeed Unreliable’ actions in accordance with the Quick Reference Handbook (QRH). In the final stage of the approach the airspeed and altitude returned to normal and the aircraft landed without further incident.

Subsequent diagnosis found the right (first officer’s) pitot probe to have a fault with its ice and rain protection heating element. Ordinarily this would not have affected the operation of the probe but the aircraft had encountered light icing conditions during its descent. Without the protection afforded by the pitot heater, it is likely that an ice restriction developed within the tube, corrupting pitot pressure data fed into the aircraft system".

=AAIB Conclusion=
The erroneous airspeed and altitude indications were likely to have been caused by partial and transient ice blockage of the first officer’s pitot probe whilst in light icing conditions. This was as a result of the failure of pitot probe heating element. The partial icing conclusion is supported by the fact that the blockage alleviated itself during the final approach when the IAS and ALT information returned to normal"

A similar event, to a Boeing 737-8AS, EI-DWS, is included in AAIB Bulletin (published 11 August 2016). (This is a reference to a Ryanair aircraft, which was involved in a very similar incident the next day (9 January 2016) at Liverpool John Lennon International Airport)

1. AAIB Report: https://assets.publishing.service.gov.uk/media/578df0f5e5274a0da3000176/Boeing_737-86N_EI-FHG_08-16.pdf
2. https://www.planelogger.com/Aircraft/Registration/EI-FHG/829443
3. https://www.flightradar24.com/data/aircraft/ei-fhg/
4. https://en.wikipedia.org/wiki/Gatwick_Airport

Other occurrences involving this aircraft


29 February 2024	OK-TST	Sunwing, opb Smartwings	0	Ottawa-Macdonald-Cartier International Airport, ON (YOW/CYOW)		sub
Collision with Ground support equipment

Boeing 737-86N (c/no. 37884, l/no. 3223. Built 2010). Originally registered as LN-NOJ. Departing on flight IBK2435 to London Gatwick. Photographed at Tenerife South Airport, Tenerife (TFS/GCTS) 17 January 2016:

Date/time	Contributor	Updates
10-May-2024 17:43	Dr. John Smith	Added
10-May-2024 17:46	ASN	Updated [Aircraft type, Departure airport, Source, Embed code, Accident report]