Turbo Otter Crash, Mayo, Yukon

[J31]

We should learn from these tragedies.......BUT pilots and operators are still skirting around the duty reg's, flight time reg's, oxygen reg's, under recording Journey log entries.......

The TSB report on this in-flight breakup of the single otter powered by the Garrett turbine.

3.1 Findings as to causes and contributing factors

The aircraft departed controlled flight for reasons which could not be determined, and broke up due to high speed.
3.2 Findings as to risk

Inaccurate journey log time entries by pilots may have a negative bearing on pilot duty time monitoring and aircraft maintenance schedules.

Pilot exceedance of duty time, such as the 60 hours flight time allowed by regulation for the 7-day period, may increase the risk of fatigue.

Non-adherence to Federal Aviation Administration (FAA) Advisory Circular (AC) 23-14 during both the supplemental type certificate (STC) approval process and the familiarization of the STC by Transport Canada may have reduced the safety margins envisaged by AC 23-14, in turn increasing risk for loss of aircraft structural integrity.

The operation of unpressurized aircraft at higher altitudes without supplementary oxygen may increase the risk of adverse effect on reaction time and judgment.

If owners of a DHC-3 Otter converted in accordance with STC SA02-15 are unaware of or have not complied with AD 2011-12-02, the aircraft may be at risk for loss of structural integrity due to operation at speeds in excess of those determined to be safe by the FAA.

The company practice of reconciling flight time and flight duty times on a monthly rather than a daily basis was inadequate to ensure compliance with CARs flight time and flight duty time limitations and rest period requirements.

If cockpit or data recordings are not available to an investigation, the identification and communication of safety deficiencies to advance transportation safety may be precluded.

If companies do not proactively monitor flight data, the identification and correction of safety deficiencies may be precluded.

Identifying human factors is critical to understanding why accidents happen. If companies cannot use voice and video recordings proactively for safety purposes, they are deprived of opportunities to reduce risk and improve safety before an accident occurs.

3.3 Other findings

While not considered a factor in the occurrence, the threaded barrel on the aileron balance cable turnbuckle was not lockwired.

While not considered a factor in the occurrence, the P2T2 loading spring assembly in the FCU contained incorrect parts from an unknown source.

http://www.tsb.gc.ca/eng/rapports-repor ... 1w0048.asp

[Rudy]

Don't exceed your duty times, don't log block flight time, don't fly high without 02 or your plane will fall apart. Thanks TSB.

The aircraft had been involved in a minor incident at the staging area on the Withers Lake ice strip on the second flight to Withers Lake on the morning of the accident. After landing, as the pilot was taxiing to position the aircraft for unloading, the aircraft struck a pile of lumber. The contact point was the left side of the fuselage, about 2 feet above ground immediately forward of the tail wheel. Following the incident, the pilot , with the help of an expeditor at the site, pushed on the tail of the aircraft to reposition the aircraft for taxi:the expeditor pushed on the right side of the aft fuselage, immediately below the right horizontal stabilizer, while the pilot pushed on the rudder. As the pilot was pushing on the rudder, a loud bang came from the aft fuselage.

The aircraft was unloaded and flown back to Mayo. Efforts during the investigation to determine the source of the abnormal bang were unsuccessful. The incident had not been reported to Black Sheep Aviation maintenance staff, and the empennage had not been inspected for associated damage by maintenance personnel before the accident. Detailed post-accident examination of the wreckage did not identify any damage that could be associated with the incident. The aircraft flew approximately 2.2 hours after the incident, prior to the accident.

[J31]

All the information indicates the aircraft broke up way above its designed speed.

For unknown reasons the aircraft started into a slight left hand descending turn accelerating from 144 mph to well over 200 mph. They believe it broke up between 224 and 256 mph in a 70 degree nose down attitude. I suspect the tail came off well above 200 mph.

We will never know the cause. Pure speculation on my part but fatigue combined with altitudes above 10000 feet could have contributed to the pilot becoming incapacitated.......fell asleep resulting is the aircraft departing from controlled flight.

[pelmet]

While I am not familiar with the circumstances of this accident, I have found with many TSB reports where they cannot conclude with specific evidence for an accident, they appear to try to get across their feeling of why it happened to the reader in such a way where, if you read between the lines, you as the reader will perhaps come to the conclusion that they want you to.

Reading just what was posted above from the report, it appears that the TSB has written the report in a way where what J31 posted would be the logical conclusion of the average reader. Yet if directly asked, the TSB could safely say that they never concluded this in their report.

If that makes sense.

[frozen solid]

The TSB as much as says in their report they have no idea at all what happened here. As non-constructive as it may be to say this, I respectfully disagree with J31 for the simple reason that, in my gut, the "falling asleep" theory feels incorrect. I don't have a scientific reason for this other than I feel that unless he fell so deeply asleep that he slumped over the controls and forced the nose down and didn't wake up right away when the aircraft departed level flight, this doesn't feel right to me. You'd have to point a single otter almost straight down to achieve the kind of speeds they're talking about here. A young, healthy guy (even with a heart murmur) isn't going to pass out like that at only 11,000 feet. The otter is a slow, dopey aeroplane that isn't going to go that far out of whack if you fall asleep. Personally I think something mechanical happened, but we will never know.

[gordon2buzzy]

4 years today since that horrible crash that took Brad from us. His spirit lives on in Ben and Bradlee and Cathy, and in the hearts and minds of all who knew him. Cathy has devoted all of her time and effort to ensure that their children thrive and remember their wonderful father. Somehow, we feel that Brad is comforted to know that his family is now well re-established, surrounded by lots of loving family and friends. Brad, we miss you beyond what words can describe and feel the pain of your loss every day. We could really use one of your rib-crushing hugs.

[I_Heart_Seaplanes]

Thanks for the update on Cathy, Benji and Bradlee. It is comforting to know that they are doing well.

Shit I miss that guy a lot

[pilotidentity]

Had a couple beers with friends Brad, shed a few tears.

[Siddley Hawker]

With reference to the loud bang heard after they pushed on the tail, was there any report on how the tailwheel steering worked after that? Just curious.