Aviation Safety Letter 2/2005

Recently Released TSB Reports

The following summaries are extracted from Final Reports issued by the Transportation Safety Board of Canada (TSB). They have been de-identified and include only the TSB's synopsis and selected findings. For more information, contact the TSB or visit their Web site at http://www.tsb.gc.ca/. - Ed.

TSB Final Report A03A0013 - Fuel Starvation/Forced Landing

Fuel Starvation/Forced Landing

On February 4, 2003, a single-engine Cessna 188B aircraft was being ferried from Canada to Africa and was en route from St John's, N.L., to Goose Bay, N.L. On the first leg of the trip, approximately 1 hr 30 min into the flight, the pilot attempted to transfer fuel from a modified fuel tank to the wing tanks. The engine stopped producing power, and the pilot then carried out a forced landing in a snow-covered frozen bog. The aircraft nosed over during the landing roll and came to rest in a nose-down attitude. The pilot was not injured.

An overflying aircraft received the MAYDAY call sent out by the pilot, proceeded to the given coordinates, located the occurrence aircraft, and reported one person standing outside the aircraft. The Halifax rescue co-ordination centre (RCC) requested an AS350 helicopter, which was on a training flight, to proceed to the crash site for pickup. The helicopter arrived at the crash site approximately one hour after the accident, picked up the pilot, and transported him to Deer Lake, N.L.

Findings as to causes and contributing factors

  1. Water contamination in the fuel system led to internal corrosion and solid particle contamination of the fuel screens. The contamination and water/ice led to a complete blockage of fuel flow to the engine, and the engine stopped.

  2. The operator dismissed the fuel transfer problem on the initial ferry flight attempt as being caused by improper operation of the fuel system. The operator did not ask the maintenance company, which was contracted only to carry out specific tasks, to do a thorough inspection of the ferry tank fuel system.

  3. An adequate examination of the fuel system after the initial ferry flight attempt would probably have revealed discrepancies (such as an improperly operating fuel system or fuel contamination) that would have been corrected before the second ferry flight attempt.

TSB Final Report A03P0239 - Collision with Terrain

Collision with Terrain

On August 10, 2003, a Cessna 210A aircraft with a pilot and one passenger aboard was on a visual flight rules (VFR) flight from Prince George, B.C., to Princeton, B.C. On reaching Princeton, the pilot joined a left-hand downwind pattern for Runway 03 and intercepted the final approach path at approximately 5 NM from the aerodrome. Approximately 3 NM from the aerodrome, the aircraft was slightly high and the pilot selected idle power and extended the landing gear. When the throttle was selected to idle, the pilot smelled fuel fumes. On final approach for Runway 03, the pilot advanced the throttle to correct the descent, but the engine (Teledyne Continental Motors IO 470-E) did not respond, even at full throttle.

The pilot checked that the fuel selector valve was in the left-tank detent, confirmed that the propeller was in fine pitch, and that the mixture control was selected to rich. Before he could turn on the auxiliary fuel pumps, the aircraft's landing gear contacted the tops of a stand of trees. The aircraft continued its descent, struck an unoccupied house and a large pine tree, and came to rest less than 1/2 NM short of the runway. The aircraft remained wings-level before and after the aircraft struck the trees. The accident occurred at approximately 16:38 Pacific Daylight Time (PDT). The pilot and the passenger suffered serious injuries; both were wearing seat belts and shoulder harnesses. There was no fire following the accident.

Findings as to causes and contributing factors

  1. On approach, when the pilot attempted to add power, the engine did not respond and the aircraft struck trees before the pilot could identify and correct the situation. The engine stopped for undetermined reasons.

  2. The deteriorated condition of the O-ring installed in the left-tank supply port prevented the fuel selector from operating normally, such that it could allow fuel to be supplied to the engine when the selector was in the OFF position.

Other findings

  1. No fault was found that would be expected to prevent the engine from producing power.

  2. It is unlikely that either fuel tank venting, fuel starvation, or fuel exhaustion of one tank precipitated this event.

TSB Final Report A03P0268 - Collision with Dock

On September 3, 2003, a de Havilland DHC-6 (Twin Otter) floatplane, with 2 pilots and 11 passengers on board, was at the dock preparing for a charter flight from Vancouver Harbour, B.C., to Victoria, B.C. The No. 2 (right-hand) engine was started normally and the pilot-in-command (PIC) signalled to the dockhand to untie the aircraft. The dockhand responded by disconnecting the auxiliary power unit (APU), confirming the untie signal, and untying both mooring lines from the dock.

The PIC then initiated the start of the No. 1 (left-hand) engine. During start, the unsecured aircraft drifted free and swung right to a position approximately perpendicular to the dock. As the No. 1 engine spooled up, and with reverse selected on the No. 2 engine, the aircraft began to accelerate forward and veer in a left-hand arcing turn toward an adjacent dock. The PIC attempted to stop the forward motion of the aircraft by applying full reverse with both engines. Unbeknownst to the PIC, a mechanical fault did not allow the propellers to go into reverse, and the increase in power accelerated the aircraft toward the dock; the PIC shut the engines down using the fuel control levers. The aircraft struck the dock and the left float was ripped from its mounts, allowing the aircraft to tip to the left as the float sank. The 13 people aboard the aircraft escaped onto a maintenance float; there were no injuries. The accident occurred at 10:20 PDT.

Collision with Dock

Findings as to causes and contributing factors

  1. The PIC deviated from the normal start and untie procedure used at the company's home base, and the PIC did not fully brief either the first officer or the involved dockhand on the departure procedure. As a result, the aircraft was not securely tied to the dock during the left engine start.

  2. An isolated wire bundle from an unused glow plug ignition system blocked the operation of the power-lever microswitch and restricted the propellers from moving into reverse pitch range.

  3. The PIC's attempt to retard the forward movement of the aircraft by applying increased reverse power had the opposite effect and accelerated the aircraft forward until it struck the adjacent dock.

Findings as to risk

  1. Moving parts of the power-lever-controlled microswitch are exposed in an area where adjacent wires may impede normal operation of the microswitch.

Other findings

  1. The PIC had insufficient time to respond to the abnormal control situation.

Safety action taken

Following this occurrence, the company involved inspected all of the aircraft in its fleet to ensure there were no similar risks to the operation of the microswitch; none was found.

Transport Canada reviewed Bombardier Service Bulletin (SB) 6/527 with Bombardier Aerospace and is currently working with the company to incorporate additional instructions with regard to isolating and stowing unused wires in the vicinity of the power-lever microswitch. Transport Canada is of the opinion that these additional instructions will help reduce the likelihood of interference.

TSB Final Report A03W0202 - Controlled Flight into Terrain (CFIT)

On September 23, 2003, a Cessna 414A departed Cranbrook, B.C., at approximately 19:10 Mountain Daylight Time (MDT) on a VFR cargo flight to Calgary, Alta. The aircraft disappeared from the Calgary area radar at 19:36 MDT, at an indicated altitude of 9 000 ft ASL in the Highwood Range mountains, approximately 49 NM southwest of Calgary. The aircraft wreckage was found on a mountain ridge at 8 900 ft ASL some 40 hr later. The flight was in controlled descent to Calgary when the impact occurred. There was a total break-up of the aircraft, and the pilot, the lone occupant, was fatally injured. There was a brief fireball at the time of impact.

Findings as to causes and contributing factors

  1. The pilot lost situational awareness, most likely believing he was over lower terrain.

  2. The aircraft was very likely flown into cloud during a day VFR flight, which prevented the pilot from seeing and avoiding the terrain.

Findings as to risk

  1. The aircraft was not required by regulation to have terrain avoidance equipment installed, leaving the pilot with no last defence for determining the aircraft's position relative to the terrain. This is a risk for all aircraft operated in similar conditions.

Other findings

  1. The flight plan was prematurely closed by NAV CANADA, which caused the early stoppage of search and rescue (SAR) activities and delayed the recommencement of those searches by 2 hr.

Safety action taken

The operator has received approved amendments to its Operations Manual that require higher/further clearances from obstacles on all day and night VFR flights. It has also implemented additional training on clearances for VFR flights and CFIT awareness.

Since the occurrence, NAV CANADA has increased the ability of Calgary tower and Edmonton flight information centre (FIC) personnel to search computer records for positive information on aircraft arrival and departure, with options for search by registration or time frame. This increased ability will reduce reliance on memory. In addition, the Edmonton area control centre (ACC) shift managers and the Edmonton air traffic operations specialist, located in the Edmonton ACC, now have access to the same computer records for search capabilities. A similar system is being beta tested in two centres and will be considered for national deployment.

TSB Final Report A03W0210 - Loss of Control/Stall

On October 4, 2003, a float-equipped Piper PA-18-150 departed Tootsie Lake, B.C., at 11:19 PDT on a day VFR flight to Linda Lake, B.C. The purpose of the flight was to transport moose meat, antlers, and camp materials located at the outfitter's camp at Linda Lake to the outfitter's base camp at Tootsie Lake.

The aircraft was not heard from after it departed Tootsie Lake. At 12:28 PDT, the SAR Satellite System received an ELT signal, and the aircraft was subsequently reported overdue. A helicopter was chartered out of Watson Lake, Y.T., to conduct a search; the wreckage was found on the shoreline of Linda Lake at 16:02 PDT. The aircraft was substantially damaged, and the pilot, the lone occupant, sustained fatal injuries. There was no post-impact fire.

The aircraft weight at the time of the accident exceeded the maximum allowable take-off weight by at least 162 lbs. Combined with the effects of the moose antlers being carried externally, this would have reduced the aircraft's flight performance; adversely affecting the stability and slow flight characteristics, and increasing the stall speed. The lack of a stall warning system may have delayed the pilot's recognition of the approaching stall. Carriage of external loads, such as moose antlers, is considered an acceptable practice by outfitters and other float plane operators. The risks associated with the carriage of external loads require that consideration be given to the performance degradation.

Loss of Control/Stall

Findings as to causes and contributing factors

  1. The aircraft stalled at low altitude, which precluded an effective recovery; the aircraft was not fitted with a stall warning system, which may have delayed the pilot's recognition of the impending stall.

  2. The combination of the aircraft being at least 162 lbs above the maximum seaplane weight of 1 760 lbs and the moose antlers being carried externally degraded the performance of the aircraft.
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