Incident Overview
On 8 November 2018, a Bombardier DHC 8-Q400 (registration SP-EQL) operating a flight was conducting an approach to land at Kraków-Balice Airport (EPKK) when the crew observed a hydraulic fluid leak from the No. 1 hydraulic system. After consulting with the operator's Maintenance Coordination Centre (MCC) and Operations Safety Department (OPS), the decision was made to return to Warsaw Chopin Airport (EPWA).
During the return flight, the crew executed the Quick Reference Handbook (QRH) checklist for "LOSS of ALL FLUID from No.1 HYDRAULIC SYSTEM". The landing was performed with the flaps retracted (FLAP 0) and with the normal and anti-skid brakes unavailable, requiring the use of the emergency brake procedure. Due to an elevated approach speed (VREF) and the absence of effective braking, the crew decided to declare an emergency landing and informed the cabin crew. The landing was completed without any consequences.
Findings
The Polish State Commission on Aircraft Accident Investigation (PKBWL) reviewed the incident and accepted the final report submitted by the operator. The investigation determined that the cause of the incident was damage to the seal at the connection of the manifold valve in the hydraulic system. No contributing circumstances were identified.
Probable Cause
Damage to the seal at the manifold valve connection.
Preventive Actions
The operator conducted inspections of seals on all manifold valves across its fleet of DHC 8-Q400 aircraft. No additional safety recommendations were formulated.