Jazz DH8D at Edmonton on Nov 6th 2014, right main gear collapse on landing, runway excursion, propeller blade(s) impacted fuselage

Last Update: April 7, 2016 / 16:03:12 GMT/Zulu time

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Incident Facts

Date of incident
Nov 6, 2014

Classification
Accident

Aircraft Registration
C-GGBF

ICAO Type Designator
DH8D

On Apr 7th 2016 the Canadian TSB released their final report concluding the probable causes of the accident were:

Findings as to causes and contributing factors

The number 3 tire ruptured on takeoff, most likely as a result of impact with a hard object.

During landing, the failed number 3 tire was spun by contact with the ground and was maintained at a rotational speed that was the same as or very close to one of the natural frequencies of the main landing gear. This caused the lock links to trigger the proximity sensor electronic unit to de-energize the solenoid sequence valve, thereby relieving system pressure from the extend port of the unlock actuator.

The excessive vibration caused the lock links to overcome the force from the downlock springs and unlock the stabilizer brace as a result of gear dynamics, which led to collapse of the right main landing gear.

Findings as to risk

If there are no specific requirements for dynamic vibration testing of components or completed airframes, there is a risk that similar or other aircraft systems could fail during high-vibration conditions.

Other findings

Short-radius turns with hard braking may cause an extreme shearing force on the tread area and on the sidewalls of the number 3 tire in particular, because it is the pivot point.

The TSB reported that during the takeoff run from Calgary a noticable vibration occurred as the aircraft approached Vr, the vibration ceased after becoming airborne. After the gear was retracted and the aircraft established in the climb the flight crew began to discuss the vibrations, cabin crew informed the flight crew that the #3 tyre (inboard right hand) had blown and something had impacted the aft fuselage.

The crew consulted with company dispatch and maintenance, a return to Calgary was ruled out because of cross winds. It was decided to divert to Edmonton for a landing on runway 02. On approach the gear indicated down and locked.

2.4 seconds after touchdown, the nose gear was still airborne, a pronounced vibration started as the main wheels spun up, and the right main landing gear collapsed, the right hand propeller struck the runway surface with all propeller blades sheared. One large section of a propeller blade penetrated the passenger cabin near seat row 7. At the same time the propeller blades made contact with the runway surface the nose gear touched down hard, both nose tyres blew, the aircraft veered to the right and came to a stop at the right runway edge 3200 feet past the point of first touchdown.

The flight data recorder revealed that the aircraft touched down at 118 KCAS with a vertical acceleration of +1.05G, a full weight on wheels indication occurred 1.5 seconds later at 114 KIAS at +1.07G, the throttles were pulled below flight idle and the propellers entered beta range.

2.3 seconds after the full weight on wheels (WOW) indication the aircraft rolled to the right consistent with the collapse of the right main gear at about 105 KCAS, a +2.68G vertical acceleration was recorded as the aircraft rolled right and contacted ground.

Three passengers received minor injuries, mainly blunt-force injuries, abrasions and small puncture consistent with plastics pieces of the cabin (side wall, window) blowing into the seat area as result of the propeller blade impact.

The TSB reported following safety actions were taken by Jazz and other operators:

Immediately after the accident, management of Jazz Aviation decided to mitigate any possible future damage from MLG tires and no longer use retreaded tires on the MLG of its DHC-8-Q400 fleet, effective 10 November 2014.

Jazz Aviation has made changes to its DHC-8-Q400 Line Indoctrination Guide – Pilot Line Indoctrination, items 14 and 30, to avoid the use of braking and tire pivot whenever possible. The company has also made changes to volume 2 of its aircraft operating manual and issued a memo (Q400 Memo 2014-131) that addresses Q400 gate arrival and departure taxi techniques, in order to lessen stresses on the main landing gear tires.

Other operators that use this aircraft have changed operational procedures to mitigate effect of the sharp right turns on the ramps near the gates in order to lessen the extreme shear loads primarily affecting the number 3 tires.
Aircraft Registration Data
Registration mark
C-GGBF
Country of Registration
Canada
Date of Registration
Kbmijj mlcnem Subscribe to unlock
Certification Basis
JjApibqdehdcAAihimlihgpqpfm ngpg fljfdjdddlpe Subscribe to unlock
TCDS Ident. No.
Manufacturer
Dehavilland
Aircraft Model / Type
DHC-8-402
ICAO Aircraft Type
DH8D
Year of Manufacture
Serial Number
Aircraft Address / Mode S Code (HEX)
Maximum Take off Mass (MTOM) [kg]
Engine Count
Engine Type
Main Owner
NjfieiiimAAAhinApcdedenpAfdpnqcchmfndbniieqgbqgn AiccfqjnqmbeAk ffej f nlljjbp nqngceAdnlcedAmkndddgbhAnmncdpcgii Subscribe to unlock

Aircraft registration data reproduced and distributed with the permission of the Government of Canada.

Incident Facts

Date of incident
Nov 6, 2014

Classification
Accident

Aircraft Registration
C-GGBF

ICAO Type Designator
DH8D

This article is published under license from Avherald.com. © of text by Avherald.com.
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