Pilot Debrief

AIRBUS AS350 near Juneau, AK — 2016-05-05

Final reportANC16LA022
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Date
2016-05-05
Location
Juneau, AK, USA
Aircraft
AIRBUS AS350
Registration
N194EH
Category
Helicopter
Highest injury
Serious
Fatalities
0
Phase of flight
Approach

Probable cause

The pilot's failure to maintain terrain clearance while on approach to land in flat light conditions. Contributing to the severity of the pilot's injuries was the inadequately restrained internal cargo, which shifted forward during the impact and struck the pilot and/or the pilot's seat.

Contributing factors

Contributing to the severity of the pilot's injuries was the inadequately restrained internal cargo, which shifted forward during the impact and struck the pilot and/or the pilot's seat.

NTSB narrative

The instrument-rated commercial pilot was making a visual flight rules internal-cargo company flight in the helicopter. He reported that flat light conditions were present as he made a visual approach for landing at a remote dog camp situated on a glacier. During the approach, the helicopter impacted terrain, coming to rest about 3/4 mile from the dog camp. The pilot reported that there were no preimpact mechanical anomalies with the helicopter and characterized the accident as controlled flight into terrain. It is likely that the pilot failed to maintain terrain clearance due to his inability to distinguish distances and closure rates because of the flat light optical illusion. The single cargo strap securing a plastic box containing a metal heater to the rear cabin floor remained intact during the accident sequence; however, the plastic box shifted forward due to the momentum of the helicopter impacting terrain, which allowed the metal heater to escape from the lidded box. It is likely that the metal heater struck the pilot and/or the pilot's seat in the accident sequence, contributing to the serious injuries sustained by the pilot. The single cargo strap used to secure the plastic box was installed such that it provided lateral restraint of the box but no forward restraint of the box. If the box had been restrained to prevent forward movement, it is likely that the metal heater would not have escaped from the box. Review of the helicopter's rotorcraft flight manual (RFM) revealed that it provided only a total weight limit for the rear cabin floor and did not provide any guidance about how to properly secure internal cargo in the cabin. Further, although the manufacturer indicated in a systems manual that cargo could be secured to the cabin floor using 11 mooring points embedded into the floor and provided a force limit for each mooring point, the systems manual provided no guidance regarding how the cargo should be attached to the mooring points; for example, no information was provided about the type and number of restraints to be used or how they should be configured. Airbus, the manufacturer of the helicopter, stated that it was the responsibility of the operator "to define an adapted cargo, freight, or baggage securement that is in respect to the limitations permissible force on the floor stowing mooring rings." The Federal Aviation Administration (FAA) stated that operators do not have certification approval to install cargo in the cabin unless it is mentioned in the RFM or RFM supplement and that, if an FAA-approved cargo configuration has been published for a specific aircraft, the RFM for that aircraft is where information on how and where to install cargo will be found. However, the FAA also stated that it "is not aware of any documentation that would prohibit Part 27 rotorcraft from carrying cargo in the cabin, even if a certification does not exist for that helicopter."

Analysis

Primary failure mode
Controlled flight into terrain
First missed decision gate
Pilot could have aborted the approach due to low visibility and flat light conditions.

NTSB coding

Evidence available

  • Video
  • ADS-B / radar
  • Photos
  • 16 docket documents
View NTSB final reportView NTSB docket

Docket documents16

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