ASN logo
ASN Wikibase Occurrence # 199301
Last updated: 25 September 2017
This information is added by users of ASN. Neither ASN nor the Flight Safety Foundation are responsible for the completeness or correctness of this information. If you feel this information is incomplete or incorrect, you can submit corrected information.

Date:06-AUG-2016
Time:03:58 LT
Type:Boeing 787
Owner/operator:
Registration:
C/n / msn:
Fatalities:Fatalities: 0 / Occupants:
Other fatalities:0
Airplane damage: None
Category:Incident
Location:Singapore-Changi International Airport (SIN/WSSS) -   Singapore
Phase: Pushback / towing
Nature:-
Departure airport:-
Destination airport:-
Investigating agency: TSIB Singapore
Narrative:
In the early morning of 6 August 2016, a tow tug was to tow a Boeing 787 aircraft to Bay 300 in Singapore Changi Airport for the aircraft to be prepared for departure. The B787 had some maintenance work done by an aircraft maintenance, repair and overhaul organisation (MRO) located on the west side of the southern end of runway 02L/20R. The towing would involve crossing runway 02L/20R via taxiway SA onto taxiway W9
The towing crew comprised the following personnel from the MRO: three aircraft maintenance engineers, a headset man and a tow tug driver. One of the aircraft maintenance engineers was designated as the Flight Deck Engineer cum Engineer-in-charge (EIC) of the towing crew. The other two engineers were assigned to carry out checks on the aircraft cockpit avionics to prepare the aircraft for departure.
The towing started from within the MRO’s premises. The EIC briefed the towing crew at about 03:30 LT and prepared the B787 for towing and conducted communications check with Changi Apron Control to test communications equipment serviceability. Then, using a tow tug of the MRO, the towing crew towed the B787 to a point on Taxiway SA such that the MRO’s tow tug was just beyond the MRO’s gate to the aerodrome. Here the MRO’s tow tug and tow tug driver were replaced by a tow tug and tow tug driver from a ground service provider (GSP) at Changi Airport engaged by the MRO.
At about 03:55 LT, while the headset man was with the replaced tow tug, the EIC and the other two engineers entered the B787’s cockpit and contacted Changi Apron Control to seek the necessary clearance for towing across runway 02L/20R to proceed to Bay 300. Changi Apron Control relayed the request to the runway controller at Changi Control Tower. The runway controller contacted the EIC on frequency 121.9MHz and said, "... expect to tow across 20R in about two ...correction, in about three minutes’ time."
The EIC thought he heard the runway controller say "...expedite to tow across the runway in 2-3 minutes’ time". Believing that it was possible to cross runway 02L/20R quickly, the EIC read back, "... we’ll cross the Runway 02L in two minutes’ time." The runway controller acknowledged with "Affirm." The towing column then moved forward. The red stop bar lights indication on the Airfield Ground Lighting Control and Monitoring System (AGLCMS) at the Control Tower was not deactivated by the runway controller.
As the towing column was moving forward, the tow tug driver spotted an aircraft approaching the airport from the north. He informed the headset man who was beside him. The headset man in turn informed the EIC. The EIC and engineers at the cockpit saw the aircraft and instructed the tow tug driver to stop. The EIC reported to the runway controller that they saw an aircraft approaching runway 02L/20R. The runway controller saw that the towing column was apparently not moving and told the EIC that he was not given clearance to cross the runway.
In the meantime, the microwave barrier detector (MBD) of the airport’s runway incursion alerting system installed at taxiway SA also triggered an alarm that alerted the runway controller.
The arriving aircraft, SilkAir flight 937 from Chengdu, operated by Boeing 737-8SA 9V-MGB, landed safely and vacated the runway at taxiway W8 without any incident. The towing column had stopped at about 115m from the centreline of runway 02L/20R (i.e. 85m from the edge of the runway).

Sources:

https://www.mot.gov.sg/uploadedFiles/Ministry_of_Transport/Content_Blocks/About_MOT/Air_Transport/AAIB/Tow%20tug%20runway%20incursion%20Changi%20Airport%206%20Aug%2016%20Final%20Report.pdf

Accident investigation:
cover
Investigating agency: TSIB Singapore
Status: Investigation completed
Duration: 1 year
Accident number: AIB/AAI/CAS.123
Download report: Summary report

Images:


Revision history:

Date/timeContributorUpdates
31-Aug-2017 18:36 harro Added
31-Aug-2017 18:41 harro Updated [Photo, ]
31-Aug-2017 18:51 harro Updated [Source]

Corrections or additions? ... Edit this accident description