Country
Crash of a BAe 125-600A in Las Vegas
Date & Time:
Aug 17, 1999 at 1817 LT
Registration:
N454DP
Survivors:
Yes
Schedule:
Salina - Las Vegas
MSN:
256044
YOM:
1974
Crew on board:
2
Crew fatalities:
Pax on board:
6
Pax fatalities:
Other fatalities:
Total fatalities:
0
Captain / Total hours on type:
275.00
Copilot / Total hours on type:
700
Aircraft flight hours:
5753
Circumstances:
The pilot landed with the landing gear in the retracted position, when both the main and auxiliary hydraulic systems failed to extend the gear. The airplane caught fire as it skidded down the runway. The left inboard main tire had blown on takeoff and a 30-inch section of tread was loose. Black marks were along the length of the landing gear strut and up into the wheel well directly above the left inboard wheel. The normal and emergency hydraulic systems both connect to a common valve body on the landing gear actuator. This valve body also had black marks on it. A gap of 0.035 inch was measured between the valve body and actuator. When either the normal or auxiliary hydraulic system was pressurized, red fluid leaked from this gap. Examination revealed that one of two bolts holding the hydraulic control valve in place had fractured and separated. The fractured bolt experienced a shear load that was oriented along the longitudinal axis of the actuator in a plane consistent with impact forces from the flapping tire tread section.. Separation of only one bolt allowed the control valve to twist about the remaining bolt in response to the load along the actuator's longitudinal axis. This led to a loss of clamping force on that side of the actuator. Hydraulic line pressure lifted the control valve, which resulted in rupture of an o-ring that sealed the hydraulic fluid passage. 14 CFR 25.739 describes the requirement for protection of equipment in wheel wheels from the effects of tire debris. The revision of this regulation in effect at the time the airplane's type design was approved by the FAA requires that equipment and systems essential to safe operation of the airplane that is located in wheel wells must be protected by shields or other means from the damaging effects of a loose tire tread, unless it is shown that a loose tire tread cannot cause damage. Examination of the airplane and the FAA approved production drawings disclosed that no shields were installed to protect the hydraulic system components in the wheel well.
Probable cause:
The complete failure of all hydraulic systems due to the effects of a main gear tire disintegration on takeoff. Also causal was the manufacturer's inadequate design of the wheel wells, which did not comply with applicable certification regulations, and the FAA's failure to ensure that the airplane's design complied with standards mandated in certification regulations.
Final Report:
Crash of a BAe 125-522-1A in Toluca: 4 killed
Date & Time:
Jul 9, 1999 at 0430 LT
Registration:
XA-TAL
Survivors:
No
Schedule:
Los Mochis – Toluca
MSN:
25064
YOM:
1965
Crew on board:
2
Crew fatalities:
Pax on board:
2
Pax fatalities:
Other fatalities:
Total fatalities:
4
Circumstances:
The aircraft departed Los Mochis Airport on a cargo flight to Toluca on behalf of DHL. On descend, the crew was informed by ATC that the visibility was reduced to 1,600 metres due to foggy conditions. While on a night approach to Toluca-Adolfo López Mateos Airport, the crew descended below the MDA, probably to establish a visual contact with the ground. On short final, the aircraft struck a two metres high concrete wall located 350 metres short of runway 15 and crashed, bursting into flames. All four occupants were killed.
Probable cause:
Controlled flight into terrain on short final after the crew decided to carry out an approach under VFR mode in IMC conditions until the aircraft impacted terrain. The following contributing factors were identified:
- Poor visibility due to foggy conditions,
- Captain's overconfidence.
- Poor visibility due to foggy conditions,
- Captain's overconfidence.
Final Report:
