Accident Cessna 750 Citation X N752TX,

Date:	Sunday 22 July 2018
Time:	15:08
Type:	Cessna 750 Citation X
Owner/operator:	Textron Inc.
Registration:	N752TX
MSN:	750-0511
Year of manufacture:	2014
Engine model:	Rolls-Royce AE3007C2
Fatalities:	Fatalities: 0 / Occupants: 8
Aircraft damage:	Substantial, repaired
Category:	Accident
Location:	Cork Airport (ORK) - Ireland
Phase:	Take off
Nature:	Executive
Departure airport:	Cork Airport (ORK/EICK)
Destination airport:	Gander International Airport, NL (YQX/CYQX)
Investigating agency:	AAIU
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
On 18 July 2018, following a flight from Luton Airport (EGGW), the aircraft landed at Cork Airport (EICK) and parked on Stand 16. After the passengers had disembarked, the two pilots carried out post-flight checks and secured the aircraft. The aircraft remained on Stand 16 until the 22 July 2018 when the pilots returned to prepare the aircraft for a flight to Gander, Canada (CYQX).
Prior to departure for CYQX, the flight crew carried out pre-flight checks of the exterior of the aircraft and cockpit setup, dividing the tasks between the two crew members.
During this process the pilot installed the Torque Link Release Pin on the nose landing gear. This pin is used to connect the upper and lower torque links on the nose gear leg to allow nose gear steering.
However, the torque links were not connected and the pin was inadvertently just installed on the upper torque link.
When the six passengers arrived, they boarded promptly and final preparations for departure were completed. The aircraft taxied the short distance from Stand 16 to runway 16 using taxiway Alpha. While taxiing, the captain experienced some difficulties in turning the nose wheel. He discussed his concerns with the Second-In-Command (SIC) who confirmed that the relevant pre-flight inspection of the nose gear had been completed. Both pilots focussed on the location of the Torque Link Release Pin (i.e. "the pin was in") and did not discuss the status of the assembly (disconnected or connected).
The aircraft turned onto the runway and began the take-off roll. At a groundspeed of 67 kts the captain aborted the take-off due to a significant vibration of the nose wheel. The maximum recorded ground speed was 74 kts, after which the aircraft decelerated and came to rest on runway 16, where it was attended by Cork Airport Fire Services (AFS). Once the AFS had inspected the aircraft, the passengers disembarked through the main cabin door onto runway 16.
The nose gear leg and nose structure of the aircraft suffered significant damage. During the accident sequence, the lower part of the nose gear leg turned through approximately 90 degrees, both tyres burst and disintegrated, leading to significant wear on the hub of the forward wheel.

Probable Cause:
1. Pre-flight checks of the aircraft exterior did not identify that the torque link assembly was disconnected.
Contributory Causes:
1. Absence of a visual warning on the torque link assembly to draw a pilots attention to an incorrectly installed Torque Link Release Pin.
2. Absence of a design feature on the torque link assembly to prevent incorrect installation of the Torque Link Release Pin.
3. The pre-flight check of the torque link assembly is merged with the checks for wheels and tires.
4. Shallow cockpit gradient.
5. The phraseology used in the aircraft Normal Checklist, pilot training and by pilots to describe the installation of the Torque Link Release Pin.
6. The AMM erroneously stated that the lower torque link was spring-loaded and would extend horizontally from the nose strut when disconnected.

Accident investigation: