Why Planes Crash Case Files: 2003: Why Planes Crash, #3

By Sylvia Wrigley

It shouldn't be possible to lose a Boeing 727.

Why Planes Crash Case Files: 2003 follows eleven aircraft disasters from 2003, detailing how the accidents happened and how they might have been avoided. This "CSI for aviation enthusiasts" series examines both the history and the current climate of aviation to unravel the instigating events which led to these catastrophes.

No one believed that a modern commercial flight could run out of fuel at 18,000 feet.

The incidents include the mystery of Air Midwest 5481 made unflyable by maintenance shortcuts, the DHL crew whose wing was shot off and an inexplicable aerobatic crash solved by DNA testing.

The windshield exploded into the cockpit. 

Every chapter features a detailed walk-through of a real-life air emergency. The author combines official investigation reports and modern media coverage as well as cockpit and ATC transcripts to take the reader through these accidents and near-misses. Why Planes Crash offers an exciting and compelling look at the critical moments which define an aviation accident, explaining both the how and the why of catastrophic accidents in modern times.

Each book in the Why Planes Crash series features detailed walk-throughs of real-life emergencies. The author offers compelling insight into the critical moments which define an aviation accident.

• Language: English
• Publisher: Sylvia Wrigley
• Release date: Nov 1, 2016
• ISBN: 9781540152602

Book preview

Introduction

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OCCASIONALLY, SOMEONE refers to this series as giving insight into the problems that plagued aviation in a particular year. This is most certainly not true. I choose the most interesting accidents and incidents, each of which highlights a different aspect of aviation. I always look to have a mix of locations, aircraft types and flights, rather than just focus on the big name commercial jets that crashed in the US and made the mainstream news. If I were to try to show typical aviation, the book would be full of general aviation pilots going out in bad weather and crashing into unexpected terrain. It would include a lot of minor issues that are aggravating but not that interesting to explore. In 2003, there would have been a dozen chapters on weight and balance issues, which seemed to plague the industry. My focus for each book has been to offer a variety of examples that help us to explore as many different aspects as possible of a single question. Why do planes still crash?

There are trends, of course, and some issues still stand: most accidents occur during take-off and landing, most accidents occur as a result of a number of issues as opposed to a single cause, systemic weaknesses generally lurk at the heart of major catastrophes. At some point, someone (the pilot, the maintenance person, the inspector, the author of the aircraft manual) makes a mistake or takes a shortcut, and this sets up a scenario that, eventually, combines with other shortcuts and mistakes until an incident is all but inevitable. Only very rarely is the accident an extreme event which could not possibly have been foreseen.

Thus, the book looks at a variety of different causes, rather than the most typical scenarios, so that we can gain understanding of the spectrum of how crashes happen and why they happen in an industry with a huge focus on safety and security.

Obviously, I can’t possibly select all the different types of accidents that could occur but I hope you will find that this edition includes a cross-section of incidents, some of which were easily avoided and others impossible to see coming. Sometimes a single action changed everything, or could have. Dismissing accidents as pilot error betrays a fundamental misunderstanding of how accidents are constructed: the pilot is generally the last barrier between an incident and an accident. He or she ends up as the final active participant in an extremely complex system, which is why the pilot’s action (or lack of it) is often the demonstrable cause. The contributing factors often include an instigating action which happened long before the flight, and it is there where we have the most opportunity for improvement. It is important to focus on how the accident could have been avoided despite human error, rather than succumb to the temptation to allocate blame.

A quick note about measurements: Modern aviation uses both imperial and metric systems based on the location of the flight. In the past, I have listed multiple measurement systems along with conversions. However, it has bothered me that the page often appears as some sort of textbook with a long blur of numbers that the reader is expected to memorise. So this time, I have simplified this to offer conversions only when it is critical to the incident and thus important for the reader to know the distance or speed or depth involved. If it isn’t particularly relevant, I simply list the measurements in the system used in the accident report, thus US reports cite feet, pounds and gallons while Russian reports refer to metres, kilograms and litres. Where an understanding of the measurements involved are required, I have done the conversions, so you should never have to look something up. However, where it is a simple issue of comparison, I have not. I hope that you will find the reports more readable, not less, as a result of this stylistic choice.

As always, I love to hear from you. If you would like to comment on this or any other aspect of the book, please feel free to email me at [e-mail]. You can also simply send the phrase crash update and I’ll make sure you get notified when the next book in the series is completed (I’m starting work on it now!).

Chapter One

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The Unstallable Plane that Stalled

THE CESSNA 185 SKYWAGON is a high wing, single engine aircraft: basically a Cessna 180 with six seats, a strengthened fuselage and a slightly more powerful engine. It’s a popular aircraft in remote areas where access to modern airstrips may be minimal. The Skywagon can be fitted with floats or skis: this particular one, registered in Finland as OH-CVT, was equipped with floats. It also had a cargo pack and a Robertson STOL (short take-off and landing) kit, which reduces the stall speed.

The aircraft was owned by Polar Lento Ltd. Originally, the aircraft and the pilot were operating under Polar Lento’s certificate. On the 30th of April 2003, however, the Finnish Flight Safety authority cancelled the certificate, as the maintenance manager of the company was not approved. Polar Lento Ltd applied for the aircraft to be added to the certificate of Ivalon Lentopalvelu Ltd. (In case I’m not the only one who wondered about the similar names: lento means flight in Finnish.) The authority added the aircraft to Ivalon Lentopalvelu’s operations on the 2nd of May 2003. The contract between the two companies stipulated that Polar Lento Ltd would cover all fixed and variable expenses of the aircraft while operated by Ivalon Lentopalvelu.

The pilot held his commercial licence and had 2,176 hours on floatplanes, most of which were on Cessna 180-types.

On the 24th of June, the day before the accident, the pilot flew the Skywagon from Lake Kilpisjärvi to Lake Ounasjärvi, Enontekiö, the Finnish part of Lapland. His fuel load had been close to the maximum when he departed Lake Kilpisjärvi. The floatplane landed at Hetta fishing harbour and docked there overnight.

The morning of the 25th, the pilot did his preflight checks and pumped the water out of the floats with a hand pump. When the passengers arrived, he weighed the baggage. He loaded some of it into the netted cargo pack under the fuselage and the rest in the cargo area behind the seats.

It’s common for flight operations in the wilderness to have the take-off weight close to the maximum. After the luggage and the passengers were loaded, the aircraft weighed 1,460 kilograms (3,220 pounds); the maximum take-off weight was 1,520 kilograms (3,351 pounds). The centre of gravity was within limits, though close to the forward limit.

They taxied from the pier to the take-off position. During the taxi, the pilot checked the engine. He then took off along the lake, heading due east into a light headwind of three knots. The waves on the lake were about 10 cm high.

When looking at the length of an aircraft’s take-off, we usually split it into two parts: the ground roll or ground run, where the aircraft is moving along the ground, and the distance from when the aircraft leaves the ground (rotation) until it reaches 15 metres (50 feet). Acceleration is based on the propeller thrust, which has to overcome the surface friction of the wheels and the aerodynamic drag of the aircraft.

On water, however, the hydrodynamic drag of the water causes the most resistance to acceleration. Take-off is effectively broken down into three phases. The aircraft starts its take-off run until the resistance reaches its peak (at about 27 knots). Then there is a short second-stage take-off phase where the floats are placed so that the aircraft is on the step: the floats have lifted partway and are hydroplaning across the surface of the water. The aircraft is no longer fully supported by the water but retains just enough surface friction to manoeuvre. Each successive wave is struck with increasing severity, so the pilot has to use elevator pressure in order to skim across the waves as the aircraft continues to accelerate. An error at this stage risks capsizing the aircraft; but soon, especially with a good head run, the aircraft will lift off the water (rotation), transitioning to the final stage of take-off.

At this stage, when the aircraft unsticks itself from the water, the pitch angle needs to be reduced—that is, the nose pitched slightly down—in order to give the aircraft a chance to gain speed. When the friction between the floats and the water disappears, the pitch up is briefly unbalanced; for how long depends on the float type. In addition, as the aircraft climbs, the ground effect reduces. The downwash behind the wing increases, the horizontal stabiliser angle of attack changes and the downward load on the stabiliser increases. As a result, the aircraft pitches up unless the pilot controls the flight path using the elevator. If this pitch up is not controlled, the aircraft is at risk of exceeding the stall angle of attack. The aircraft accelerates more easily when it is close to the water because the aircraft-induced drag is less in the ground effect. Thus, it is even more important for the floatplane pilot to control the pitch of the aircraft and gain airspeed before climbing away.

The Cessna 185’s take-off run on Lake Ounasjärvi that morning was approximately 500 metres (1,640 feet) of which the last 300 metres (980 feet) was on the step. The pilot noticed that the wind was coming slightly from the left (easterly).

The pilot had set the trim so that the aircraft would lift off from the step and begin to climb away. The rudder trim was set almost as far right as it could go. The pilot described the take-off as quick and easy. I let it lift off by itself. It was well-trimmed and it lifted off normally by itself.

The aircraft suddenly yawed and rolled to the right. They were about 15 metres above the water, ready to transition to the next phase of flight. The pilot immediately applied full opposite aileron and left rudder in an attempt to straighten out the aircraft. He pressed his right foot on top of his left foot in an attempt to gain full left rudder.

It didn’t help. The aircraft yawed more than 90° to the right; that is, it turned at a right angle to its direction of travel. The right wing tip hit the water first, throwing the aircraft into a cartwheel. The nose and right wing hit the water, followed by the empennage as the cartwheeling continued. The left door and windshield were torn off of the fuselage.

When the tail impacted the water, the aircraft capsized and came to a halt, floating upside down in the lake, buoyed up by its floats. The water at the crash site was approximately 30 metres (100 feet) deep.

The cabin roof was at a depth of two metres (6.5 feet) and the cabin filled with water immediately. 170 litres of aircraft fuel and 10 litres of engine oil spilt into the lake. The water temperature was 8-10°C (46-50°F).

The pilot unbuckled his seat and tried to undo the seat belt of the passenger in the right-hand seat next to him. He couldn’t find the buckle. The passenger didn’t move and showed no signs of life. Running out of air, the pilot had to dive to get to the surface.

The passenger in the middle row, a 14-year-old boy, unbuckled his seat belt. He saw the surface through the left door opening and dived through it and swam to the surface.

A number of people witnessed the crash. Boats raced to the capsized aircraft, arriving within three minutes of the accident. One bystander dived into the water twice to try to reach the passenger trapped in the right-hand seat. It had been five minutes since the aircraft had capsized. The diver touched the passenger’s lifeless hand but was unable to free him from the aircraft.

The Enontekiö fire brigade arrived on the scene about twenty minutes later. One of the fire brigade with scuba diving gear attempted to recover the passenger but was unable to free him. The aircraft was towed towards the Hetta shore but became stuck in the bottom of the lake about 60 metres (200 feet) from the shore.

Two hours later, another, more experienced diver arrived on the scene. He was able to release the seat belt, which had tangled