C501, vicinity Trier-Fohren Germany, 2014
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|On 12 January 2014, the crew of a Cessna 501 on a private business flight with a two-pilot crew attempted to make an unofficial GPS-based VNAV approach in IMC to the fog-bound VFR-only uncontrolled aerodrome at Trier-Fohren. However, after apparently mis-programming the 'descend-to' altitude and deviating from the extended centre, the aircraft emerged from the fog very close to the ground and after pulling up collided with obstructions, caught fire and crashed killing all occupants. The Investigation noted an apparent absence of pre-flight weather awareness beyond the intended destination and that there was a suitable fog-free diversion.|
|Actual or Potential
|Controlled Flight Into Terrain (CFIT), Fire Smoke and Fumes, Human Factors, Weather|
|Aircraft||CESSNA 501 Citation 1SP|
|Type of Flight||Private|
|Take off Commenced||Yes|
|Flight Phase||Missed Approach|
|Location - Airport|
|Tag(s)||Copilot less than 500 hours on Type|
No Visual Reference,
Vertical navigation error,
VFR flight plan
|Tag(s)||Post Crash Fire|
|Tag(s)||Data use error,|
Pre Flight Data Input Error,
Plan Continuation Bias,
Procedural non compliance
|Safety Net Mitigations|
|TAWS||Available but ineffective|
|Damage or injury||Yes|
|Aircraft damage||Hull loss|
|Fatalities||Most or all occupants (4)|
|Causal Factor Group(s)|
On 12 January 2014, the crew of a US-registered Cessna 501 on a private business flight from Shoreham UK to the uncontrolled VFR only aerodrome at Trier-Fohren Germany failed to complete a self-navigated approach to runway 22 at destination in day IMC and after it collided with obstructions during an attempt to initiate a pull up from close proximity to the ground, control was lost when a wing was severed by impact with an electricity pylon and the aircraft was destroyed by ground impact and fire killing both pilots and both passengers.
An Investigation was carried out by the German BFU. The accident aircraft was not fitted with flight recorders – nor was it required to be - but relevant recorded ATC data from both civil and military ATC Units were available.
The 55 year-old PIC held both German and US professional licences and was estimated to have approximately 4,250 total flying hours including around 1,280 on Cessna Citation variants. Several pilots who worked for the same Company described him as "rather dominant and assured of himself". The Co-pilot held a German professional licence and was estimated to have approximately 1,380 total flying hours including 250 hours on the Cessna 525 and about 39 hours on the Cessna 501. The Investigation received credible evidence that the authority gradient between PIC and the Co-pilot was "distinct" and in addition that during the preceding weekend in the UK, "there had been a dispute between the two pilots" with the PIC voicing his intention that after their return to Germany, he would have the working relationship with the Co-pilot terminated because of dissatisfaction with his work in respect of his "low skills and proficiency". It was also noted that several pilots interviewed during the Investigation had described the co-pilot as "reticent, level-headed and a co-operative team player".
The aircraft involved in the accident had been company operated for the previous 11 months for the specific purpose of performing non-commercial company flights for which it had previously chartered aircraft. It was reported that aircraft had also been used for trips made by the family of the company owner. At the time of the accident seven pilots were employed of which all but one were qualified to operate as PIC as well as SIC, the exception being the accident Co-pilot who did not hold the FAA licence and type rating needed to operate a US-registered aircraft because the aircraft owner had, contrary to the case of a number of the other pilots, not been prepared to fund the cost. The Company stated that at the time of the accident there was no Operations Manual for non-commercial company flight operations and that Flight Operations post holders had not been designated and no Standard Operating Procedures (SOPs) had been established. Although the aircraft type was certified for single-pilot operation, the Company owner required that non-public operations were always conducted with two pilots. The aircraft was equipped with both a VNAV programmable Garmin GPS 500 and a Class 'B' TAWS. Provided that it was not inhibited, the latter would have provided a red visual warning and accompanying audio annunciation if the aircraft descended to within 100 feet of terrain and it was stated that the display could show obstacles.
It was established that the aircraft had flown from Trier to Shoreham on Friday 10 January 2014 so that the two passengers "could participate in a hunt". The return flight was the accident flight and the Flight Plan filed showed a change from IFR to VFR at waypoint PITES which was a short distance south west of the destination. Shortly before departure, the PIC had telephoned Trier-Fohren aerodrome and was advised of thick freezing fog there with only the possibility of a clearance which would, if it happened, not be until the early afternoon. The aerodrome FISO to whom he had spoken subsequently stated that after this conversation, he had assumed that the flight would go to another aerodrome. There were no indications that either pilot had reviewed the latest NOTAMs or checked the weather anywhere else and when the aircraft took off from Shoreham at 1000 with the PIC as PF, neither the intended destination nor the alternate given on the Flight Plan, Luxembourg, were reporting or forecasting weather conditions sufficient for landing.
Descent under ACC radar control with descent clearance to 5,000 feet was provided and a couple of minutes later, with the aircraft tracking south, passing approximately FL 090 and 15 nm northwest of destination, IFR was cancelled. The aircraft was positioned to the Trier-Fohren runway 22 extended centreline at approximately 2,300 feet QNH and at approximately 5.7nm from the runway. As it passed 1,600 feet QNH and was approximately 4.6nm from the threshold of runway 22 and making a ground speed of about 160 knots, the aircraft began to slowly deviate to the left of the extended centreline. Shortly afterwards, a number of witnesses in a valley in the vicinity of the accident site reported having briefly seen an aircraft at a low height pass overhead and then pull up and disappear into the fog/cloud. Trees were then contacted and the right wing subsequently hit an electricity tower after which fire began and the aircraft rolled inverted and into the terrain below in a position about two miles prior to the beginning of runway 22.
The Investigation concluded that the final descent towards runway (see the reconstruction of the approximate flight path below) had been conducted by relying on the VNAV function of the GPS whilst in the complete absence of visual reference. The available evidence was considered to point to erroneous programming of the target descent altitude so that the aircraft was then unintentionally flown towards a position which was below the level of the prevailing terrain. It was surmised that cooperation between the two pilots may well have suffered due to tension between them and that effective CRM would have been compromised as a result, although there was no direct evidence of this or any part it may have played in the accident.
It was noted that the fog in the general area was widespread but not continuous - see the satellite image below - and that although a landing would not have been possible at Luxembourg, the weather at Frankfurt Hahn had been good and in line with the earlier forecast. The weather recorded at Trier-Fohren at the time of the accident included a visibility of 100-150 metres in freezing fog with a surface wind from 040° at 3-5 knots.
The Causes of the Accident were formally identified as follows:
- The Pilot in Command (PIC) decided to conduct the VFR approach even though he was aware of the prevailing instrument weather conditions at the airport.
- It is likely that a wrong vertical profile was flown due to an erroneous selection on the navigation system.
- Due to the insufficient situational awareness of the pilots, the descent was not stopped in time.
One Contributory Factor was also identified:
- Insufficient Crew Resource Management (CRM)
The Final Report was completed on 18 October 2016 and subsequently published.
The BFU noted that Part NCC of Commission Regulation (EC) No 965/2012 for non-commercial flights with technically complicated powered aircraft had come into force on 25 August 2016 and included requirements for the organisation, risk management and procedures for non-public company flights such as the accident flight and "therefore refrains from issuing safety recommendations regarding this matter".
- Controlled Flight Into Terrain (CFIT)
- Using GNSS as a VFR Navigation Tool
- Global Positioning System (GPS)
- Navigation Aids for VFR Flights
- Terrain Avoidance and Warning System (TAWS)
- Pre-flight Preparation
- Crew Resource Management
- Authority Gradients
- Non-Aerodrome FIS Outside of Controlled Airspace (UK)