Narrative:A Beechcraft 1900D, registered ZK-EAK, sustained damage in a wheels-up landing at Blenheim-Woodbourne Airport (BHE), New Zealand. There was no injury to the crew or the 15 passengers.
|Date:||Monday 18 June 2007|
|Operating for:||Air New Zealand Link|
|Leased from:||Eagle Airways|
|C/n / msn:|| UE-434|
|First flight:|| 2002|
|Total airframe hrs:||10315|
|Engines:|| 2 Pratt & Whitney Canada PT6A-67D|
|Crew:||Fatalities: 0 / Occupants: 2|
|Passengers:||Fatalities: 0 / Occupants: 15|
|Total:||Fatalities: 0 / Occupants: 17 |
|Airplane damage:|| Substantial|
|Airplane fate:|| Repaired|
|Location:||Blenheim-Woodbourne Airport (BHE) (New Zealand)
|Phase:|| Landing (LDG)|
|Nature:||Domestic Scheduled Passenger|
|Departure airport:||Timaru Airport (TIU/NZTU), New Zealand|
|Destination airport:||Wellington International Airport (WLG/NZWN), New Zealand|
The flight, operated by Eagle Airways, departed Timaru Airport (TIU) at 07:10 on a domestic service to Wellington International Airport (WLG). After take-off the aircraft was climbed to a cruising altitude of 21000 feet and the flight progressed uneventfully north towards Wellington.
At 08:12 ZK-EAK was approaching the commencement of the ILS approach and the crew started to configure the aircraft for the approach and landing. Initial flap was extended and approaching the glide path the first officer moved the landing gear lever to lower the gear, but the undercarriage failed to extend.
The first officer returned the gear lever to the up position and at 08:15 he advised air traffic control (ATC) that they had a landing gear problem and were initiating the missed approach procedure. The aircraft was climbed to above the cloud and levelled at 6000 feet. ATC gave radar vectors to take ZK-EAK initially to the west of Wellington.
The landing gear lever was selected down a second time and again there was no indication of any gear movement. The crew checked electrical switches and panels, and found nothing that would stop the gear lowering. The crew decided that before completing further fault analysis, the aircraft should be positioned in an area away from cloud and other traffic. Knowing the area around Woodbourne was clear of cloud, the first officer got ATC clearance to descend in that direction. The captain told the passengers what had happened and of their intention to divert to the Woodbourne area to hold.
The aircraft was established in a holding pattern clear of Woodbourne Aerodrome and the crew carried out the quick reference handbook (QRH) actions for manual extension of the landing gear. Control of the aircraft was passed to the first officer to allow the captain to operate the manual pump to lower the landing gear. The captain reported that as he operated the pump handle he felt no resistance or pressure that would normally be expected. After pumping the handle for some time without success, he lowered and secured the handle and assumed control of the aircraft again.
The first officer contacted the operator’s maintenance facility at Woodbourne and briefed the staff on the situation. He also advised the Woodbourne aerodrome controller. The controller replied that a full emergency response had been activated.
The crew reviewed the QRH and repeated the actions for manual gear lowering, but the landing gear remained retracted. The operator’s maintenance staff contacted the crew and offered several suggestions on possible causes and actions that might assist, including isolating electrical power to the landing gear motor, but the landing gear remained in the up position.
The crew, having exhausted all possible options to lower the landing gear and aware of the amount of fuel remaining, prepared the aircraft for a wheels-up landing at Woodbourne. The first officer left his seat and individually briefed the passengers for the landing, including what they were required to do and when and how to exit the aircraft after landing. The first officer then checked passenger security and stowed all of the cabin bags in the front row of seats before returning to his seat.
The crew reviewed the QRH actions for a wheels-up landing, and after excess fuel had been used, turned off all non-essential electrical items, including pulling the landing gear control circuit breakers to prevent uncommanded movement of the landing gear. The crew set the flap to 17º and positioned the aircraft for a landing on runway 24. At about 09:02 the aerodrome controller confirmed emergency services were in place and cleared the aircraft to land.
At about 500 feet, as ZK-EAK was turned to final approach, the first officer instructed the passengers to brace for the landing. At 09:07, ZK-EAK touched down. On first contact with the runway, the first officer started to shut down the engines while the captain kept the aircraft straight. The aircraft took nearly 15 seconds to come to a halt, after which the crew completed securing the aircraft and the passengers started to vacate the aircraft using all 4 exits.
1. The records for the aircraft showed it had been maintained in accordance with documented manuals.
2. A fatigue crack in the actuator developed over time, estimated to be about 11 900 cycles, and reached a critical size during the flight to Wellington.
3. The crack allowed hydraulic fluid to vent overboard and, because of the landing gear system design, the crew were prevented from lowering the landing gear by any means.
4. Published emergency procedures for performing a wheels-up landing, and the crew’s adherence to those procedures, mitigated as much as possible the risk of injury to the occupants of the aircraft, and minimised the damage that the aircraft sustained.
5. The decision to divert the aircraft from Wellington to Woodbourne, which had lesser emergency response capability, was reasonable because the weather conditions and environs at Woodbourne increased the chances of a successful landing, and the emergency response capability at Woodbourne was designed for such an event.
Following the discovery of the second failed actuator, an inspection regime developed by the operator helped to identify other defective actuators and prevented any further occurrences.
6. The actuator from ZK-EAK, and some other actuators on the operator’s fleet of aircraft, failed well before their intended design life because of one or any combination of the following factors:
- the original design specification not representing the actual in-flight loads and pressures on the actuator
- inadequate specification for or adherence to surface finishing during manufacture
- the internal radius of the end cap being too small
- the hard-coat anodising being more brittle and therefore more prone to cracking at lower tensile stress than the underlying compound.
7. The Commission was unable to determine the precise cause of the fatigue crack owing to conflicting evidence provided by the aircraft manufacturer and the manufacturer of the actuators over the design and construction of the actuators. This was the subject of continuing discussion between the 2 parties.
8. The judicious and combined response to the landing gear failure by the operator, the CAA, overseas safety agencies and the aircraft manufacturer in developing an inspection programme and initiating a review of the fatigue life and design of the actuator, should provide a long-term solution to the problem.
Official accident investigation report
Follow-up / safety actions
Hawker Beechcraft issued a Mandatory Service Bulletin SB 32-3870, dated April 2008 to address the issue of leaking and cracked main landing gear actuators.
FAA issued 1 Airworthiness Directive
Show all AD's and Safety Recommendations
This map shows the airport of departure and the intended destination of the flight. The line between the airports does not
display the exact flight path.
Distance from Timaru Airport to Wellington International Airport as the crow flies is 440 km (275 miles).