Crossair 3597

• On 24 November 2001 at 20:01 UTC the aircraft AVRO 146 RJ 100, registered as HB-IXM of the Crossair airline company took off in darkness from runway 26L at Berlin-Tegel airport as scheduled flight CRX 3597 to Zurich.
• At 20:58:50 UTC, after an uneventful flight, the aircraft received the clearance for a standard VOR/DME approach 28 at Zurich airport.
• Ahead of the aircraft involved in the accident, an Embraer EMB 145, flight CRX 3891, landed on runway 28 at Zurich airport. The crew informed the control tower that the weather was close to the minimum for this runway.

Source: Swiss Final Report 1793, page 11.

At 21:05:21 UTC flight CRX 3597 reported on the aerodrome control frequency. When the aircraft reached the minimum descent altitude (MDA) of 2390 ft QNH at 21:06:10, the commander mentioned to the copilot that he had certain visual ground contact and continued the descent.

Source: Swiss Final Report 1793, page 11.

• As the aircraft approached the minimum descent altitude (MDA) for the approach, the commander mentioned at 21:05:55 UTC that he had noted this and explained that he had certain visual ground contact: "Zwei vier, ground contact hämmer, hä" – Two four (2400), we have ground contact". The copilot answered: "Yes". At 21:05:59 UTC the commander stated: "Mä hät gseit, Pischte hät er spaht gseh da... approaching mini- mum descent altitude... da hämmer ächli ground contact..." – Someone said he saw the runway late here ... approaching minimum descent altitude... here we've got some ground contact.
• At 21:06:10 UTC the aircraft reached the MDA of 2390 ft QNH and the commander said: "...zwo vier, s'Minimum... ground contact han ich... mer gönd wiiter im Moment... es chunnt füre, ground contact hämer... mer gönd wiiter..." - ...two four (2400), the minimum ... I have ground contact ... we're continuing at the moment ... it appears, we have ground contact ... we're continuing on ... .

Source: Swiss Final Report 1793, page 19.

At the same time, the copilot said quietly to himself: "Two four". The descent continued unchanged below the MDA. At 21:06:22 UTC the synthetic voice of the ground proximity warning system (GPWS) announced the radio altimeter reading 500 feet above ground. Immediately thereafter, the commander stated: "*****, zwee Meile hät er gseit, gseht er d'Pischte" – *****, two miles he said, he sees the runway.

Source: Swiss Final Report 1793, page 19.

At 21:06:31 UTC the commander mentioned that 2000 feet had been reached: "Two thousand". In addition, one second later the synthetic voice gave the "minimums" GPWS message, which was triggered by the radio altimeter reading at 300 feet. At 21:06:32 UTC aerodrome control ADC 1 gave flight CRX 3597 the landing clearance. During this radio conversation, the commander said quietly: "...go around mache?" – ...make a go around? At 21:06:34 UTC the commander instructed a go around and an acoustic signal indicated that the autopilot had been switched off. A few fractions of a second later, the copilot likewise expressed the intention to go around. The recordings of the digital flight data recorder prove that the crew pushed the power levers towards the take-off thrust position and the engines' RPM increased. One second later, the CVR began to record the sounds of an impact. A short time later, the CVR recording broke off.

Source: Swiss Final Report 1793, page 19.

• At 21:06:36 UTC the aircraft collided with treetops and subsequently crashed into the ground.
• The aircraft caught fire on impact. Twenty-one passengers and three crew members died from their injuries at the site of the accident; seven passengers and two crew members survived the accident.

Source: Swiss Final Report 1793, page 11.

• The investigation has determined the following causal factors in relation to the accident:
• The commander deliberately descended below the minimum descent altitude (MDA) of the standard VOR/DME approach 28 without having the required visual contact to the approach lights or the runway
• The copilot made no attempt to prevent the continuation of the flight below the minimum descent altitude.
• The following factors contributed to the accident:
• In the approach sector of runway 28 at Zurich airport there was no system avail- able which triggers an alarm if a minimum safe altitude is violated (minimum safe altitude warning – MSAW).
• Over a long period of time, the responsible persons of the airline did not make correct assessments of the commander's flying performance. Where weaknesses were perceptible, they did not take appropriate measures.
• The commander's ability to concentrate and take appropriate decisions as well as his ability to analyse complex processes were adversely affected by fatigue.
• Task-sharing between the flight crew during the approach was not appropriate and did not correspond to the required procedures by the airline.
• The range of hills which the aircraft came into contact with was not marked on the approach chart used by the flight crew.
• The means of determining the meteorological visibility at the airport was not representative for the approach sector runway 28, because it did not correspond to the actual visibility.
• The valid visual minimums at the time of the accident were inappropriate for a decision to use the standard VOR/DME approach 28.

Source: Final Report, page 12.

The intersection point of the PAPI glide path (3.7°) with the minimum descent altitude was at a slant distance of 3.3 NM from VOR/DME KLO, or 2.4 NM (4.4 km) ahead of the runway threshold. In order to be able to see the approach lights from this point, a computed minimum visibility of 3700 m would be necessary.

Source: Final Report 1793, page 123.