Accident data for ultralight aircraft report 16

 Ultralight News
Covering the World of Ultralight Aviation





Airfield
By Appt ONLY

Click here for
Rotax Aircraft Engine Information

The L'il Buzzard ultralight trainer.

Top 10 reasons to consider a
 L'il Buzzard! 
Tower: "...and for your information, you were slightly to the left of the centerline on that approach."
Speedbird: "That's correct; and, my First Officer was slightly to the right"

 Click here for this months specials!

Your new AdDesigner.com ad! 

When was the last time you did maintenance on your K & N Airfilter? Is you filter safety wired? Click here to see how to clean and safety wire your airfilter!
 
 

AAIB Bulletin No: 2/2000 Ref: EW/G99/10/06 Category: 1.4

Aircraft Type 
and Registration:		 Kolb Twinstar MK3 (Modified), G-MYOG
No & Type of Engines: 1 Hirth 2706 R06 2-stroke piston engine
Year of Manufacture: 1994
Date & Time (UTC): 6 October 1999 at 1230 hrs
Location: 4 kilometres west of Lydd Airport, Kent
Type of Flight: Private
Persons on Board: Crew - 1 - Passengers - 1
Injuries: Crew - Serious - Passengers - Minor
Nature of Damage: Distorted cockpit frame, nose cone shattered
Commander's Licence: Private Pilot's Licence
Commander's Age: 59 years
Commander's Flying Experience: 272 hours (of which 264 were on type)
  Last 90 days - 19 hours
  Last 28 days - 6 hours
Information Source: Aircraft Accident Report Form submitted by the pilot and AAIB examination of failed crankshaft

 History of the flight

The pilot had planned a flight from Redhill to Lydd. The meteorological conditions were CAVOK in light winds with a surface temperature of +10°C. After having been airborne for about one hour the pilot contacted Lydd radio for circuit information. He then selected the alternate fuel tank which was full. Shortly afterwards the engine RPM reduced, the engine ran roughly for a few seconds and then stopped. The pilot transmitted a MAYDAY call to Lydd and then commenced his forced landing procedures. Having selected a field in which to land, the pilot experienced a steeper descent path than he had anticipated, probably as a result of the stationary propeller. In order to reach the selected field the pilot raised the nose, causing a reduction in airspeed, and he then had insufficient pitch authority to effect a controlled landing. After striking the ground heavily the aircraft came to rest inverted.

The pilot and his passenger vacated the aircraft and the emergency services quickly arrived on the scene, after the pilot had used his mobile telephone to direct them to the crash site. He reported that in hindsight he may have spent too much time describing his intended forced landing location to Lydd when he should have been concentrating on flying the aircraft.

Engine examination

Subsequent examination of the engine by the owner revealed that the crankshaft had failed immediately forward of the aft crank position. AAIB examination of the fractured surfaces revealed that the failure had occurred as a result of rotating/bending fatigue cracking at the intersection of the shaft with one of the rotating counterbalance weights, as illustrated in Figure 1. This intersection was 'sharp cornered' with little or no blend radius. Further examination of the crankshaft and its support bearings found that there was a loose fit between the crankshaft and its aft end support bearing, resulting in a radial clearance between the two (Figure 2). During running, the result of this would have been to significantly increase the bending stresses at the next bearing location, the point of failure. The fit of the other four bearings on the crankshaft was satisfactory. Since new, the engine had accumulated approximately 300 hours running time. The pilot reported that he has drawn the attention of this defect to the import agents for the engine.

Improved seat/cushion impact load attenuation

The pilot reported that Service Bulletin KSB1 had been incorporated. This introduced modification of the seat pans and cushions which he considered had absorbed a lot of the energy of the ground impact, minimising the injuries sustained.

 

DATE:                May 31 1999  20:35 Eastern Time (00:35 June 01 1999)

LOCATION:      Mouth of Chukuni River, to Keg Lake,  5.5 statue miles south of Red Lake
                            Red Lake co-ordinates: 51.04.01N - 93.47.35W

DEPARTURE:   Chukuni River, Ontario

WEATHER:        VFR

AIRCRAFT:        Beaver RX 650 Ultra-light, s/n BRX6-035, manufactured 1991,  two seater,  amphibious (float equipped).

ENGINES:           1   Rotax 503 (reported)

CREW:                 1

PASSENGERS:   1

FATAL:                2 of 2

FLIGHT:              Training - dual instruction training, local. 

DETAIL:              The ultra-light aircraft was based on the Chukuni River. The pilot recently  completed a Transport Canada ultralight instructor's examination and was awaiting his certificate. The passenger was a student. At approximately 20:35 local (Eastern Time) the attention of three witnesses familiar with observing the aircraft in flight was drawn to the ultralight.  They observed the ultra-light some distance away at an approximate altitude of 1,000 - 1,500 feet above ground banking and pitching in an erratic manner. The aircraft then descended nose down and parts of a wing appendage were observed descending separately. The ultra-light crashed in trees and a fire  ensued.

The Ontario Provincial Police (OPP) were notified at approximately 21:00 local. The aircraft was destroyed by fire and the two occupants succumbed to injuries sustained as a result of the accident.

PRELIMINARY - CAUSE OF ACCIDENT (Subject to revision)

(a)    Loss of control in flight, aerodynamic stall, failure to recover.
(b)    Failure of wing structure due to excessive gravitational forces exerted on airframe either during manoeuvre or following stall.
(c)    Exact cause leading to loss of control unknown.

CLASSIFICATION: Major

Ultralight aircraft account for a large percentage of fatal aeronautical accidents.

Five days prior to the Red Lake fatalities, an amphibious Beaver RX550 crashed at Port McNeil, British Columbia. The aircraft suddenly banked right approximately 60° at  (+/-) 1,000 feet. The pilot managed to get the nose down and gain some control preventing a stall. Following a spiralling descent, the pilot managed to stabilize the aircraft briefly before it rolled at approximately 50 feet AGL and impacted the surface of Port McNeil Harbour. The cause of the accident was attributed to an in-flight failure of the aft right wing attachment.

This accident is being investigated by the Ontario Provincial Police, the Ontario Coroner's Office, with the requested assistance of the Transportation Safety Board of Canada. 

Make yourself visible to others when your flying...... Strobe lights make you visible! Click here for more information!

Ultralight News
Covering the World of Ultralight Aviation
                

Airfield
By Appt ONLY

 

Google

 

Web Ultralight News.com

Ultralight Aircraft News Web Magazine Covering the World of Ultralight Aviation

You may link to these pages or print them out for your own personal use, but no part of this publication may be copied or distributed, transmitted, transcribed, stored in a retrieval system, or translated into any human or computer language, in any form or by any means, electronic,  mechanical, manual, or otherwise,  without the written permission of Ultralight News. By copying or paraphrasing the intellectual property on this site, you're automatically signing a binding contract and agreeing to be billed $10,000 payable immediately. Copyright Ultralight News  
Return to Main Index for this section