Martinair Flight 495

Martinair Flight 495 was a McDonnell Douglas DC-10 operated by Dutch airline Martinair, that crash-landed in severe weather conditions at Faro Airport, Portugal on 21 December 1992. The aircraft carried 13 crew members and 327 passengers, mainly holidaymakers from the Netherlands. 54 passengers and 2 crew members died. 106 of the other occupants were badly injured.

Aircraft and crew

The aircraft involved was a McDonnell Douglas DC-10-30CF, registered ''PH-MBN'', which was built in 1975 carrying the serial number 46924.airfleets.net – McDonnell Douglas DC-10 – MSN 46924 – PH-MBN
retrieved 2 July 2016 The aircraft was named Anthony Ruys in honor of one of Martinair's former commissioners. It was delivered to Martinair on 26 November 1975. However, Martinair leased it out to three Asian airlines from October 1979 to September 1981. From then on until the accident, only disrupted by a short lease to World Airways in early 1992, it was solely operated by Martinair again, although it had been sold earlier that year to the Royal Netherlands Air Force for a planned conversion into a KDC-10.

The captain was 56-year-old H. Willem van Staveren, who had been with Martinair since January 1968. He was a DC-10 flight instructor and had a total of 14,441 flight hours. He previously served in the Royal Netherlands Navy from 1962 to 1966 and had worked for Schreiner Airways from 1966 to 1968.

The first officer was 31-year-old Ronald J. H. Clemenkowff. He had been with Martinair for three years and had 2,288 flight hours, with 1,787 of them on the DC-10.

The flight engineer was 29-year-old Gary W. Glans, who had been with Martinair for only eight months. However, he had worked for both Canadian Airlines and Swissair from 1988 to 1992. Glans had a total of 7,540 flight hours, including 1,700 hours on the DC-10.

Description

Departure

On the morning of the accident, the plane was delayed at Amsterdam Airport Schiphol because of a faulty thrust-reverser. This was not fixed. Nevertheless, the plane took off to Faro at 04:52 UTC. According to Martinair, the faulty thrust-reverser was not a contributing factor in the accident.

Crash

A large thunderstorm lay in the immediate vicinity of Faro airport, accompanied by heavy rain, windshear and low cloud. The control tower informed the crew of the thunderstorm activity, in addition to stating that there was water on the runway. Following one unsuccessful landing attempt the crew attempted a VOR/ DME procedure approach to runway 11 (later runway 10) during which the aircraft flew through at least two microbursts. According to the Portuguese final accident report, firefighters saw an explosion coming from the aircraft 22 seconds before it crashed.

The aircraft landed with a vertical speed exceeding the manufacturer's design limits. Following this hard landing, the starboard main gear collapsed. The starboard wing separated from the fuselage and the starboard fuel tank ruptured and the contents ignited. The DC-10 fuselage split in two, coming to rest with the front section lying on its side.

Causes

There are different opinions about the causes of the air disaster.

According to the official investigation by the Portuguese aviation authorities

According to the Portuguese aviation authorities (DGAC), the causes of the air disaster were likely to have been:

* the high sink rate in the last phase of the approach;
* the landing on the right landing gear, which exceeded the structural limitations of the aircraft;
* the transverse wind during the final approach and landing which exceeded the design limits of the landing gear given the flooded condition of the runway;

The DGAC describes as additional factors:

* the instability of the landing approach;
* the pilots' reducing throttle too early and allowing the aircraft to lose altitude in an unsafe manner;
* the airport providing incorrect wind information for the approach;
* the absence of an approach light system;
* the incorrect assessment of the condition of the runway by the crew;
* the overriding of the autopilot just before the landing, whereby the aircraft was flown manually in a critical phase of the landing;
* the delay by the crew in increasing altitude;
* the decrease of the aircraft's lift coefficient due to heavy rainfall.

According to the Dutch aviation authorities

The Dutch Office for the Investigation of Accidents and Incidents of the National Aviation Authority (RLD) indicated that the probable cause should be as follows:

* a sudden and unexpected variation in wind direction and speed (windshear) in the last phase of the approach;
* a high descent speed and extreme lateral displacement which caused an excessive loading of the right landing gear, which in combination with a considerable angular displacement exceeded the structural limitations of the aircraft.

According to the RLD, additional factors were:

* that the crew of flight MP495 did not expect the occurrence of windshear on the basis of the weather forecast and weather conditions;
* the premature reduction of engine power, most likely due to the action of the crew;
* the disabling of the autopilot just before landing, whereby the aircraft was manually flown in a critical phase of the landing.

2011 research and lawsuits

On 14 February 2011, the ''Algemeen Dagblad'' reported among other things about a new investigation, which was carried out by researcher Harry Horlings at the request of relatives. According to Horlings, there was no wind shear at the Faro disaster and the pilots had made serious mistakes. According to Horlings, the data from the black box was incomplete in the Dutch report from 1993; the last seconds were missing. In the cover letter to the report of the American Aviation Service, in which the data from the black box were presented, it was indicated that the autopilot had been used incorrectly. The report also recommended improving the training of pilots.

The Dutch Safety Board