2001 Pensi La Mid-air Collision

A diagram showing where the wing struck

## KLM Flight 147

A KLM 737-300 similar to the one involved in the accident.

## Introduction

**2001 Pensi La Mid-air Collision** was an aviation incident involving a KLM Boeing 737-200 and a British Airways Boeing 747. The accident killed 356, making it the worst mid-air collision in history (not actually).

## Pilots

### KLM Flight 147

Captain Rochus Kuijpers and First Officer Gerlof Klaasen flew the flight, and they had a total 8,600 hours.

### British Airways Flight 372

Captain Jack Gielbert and First Officer Edward Walters were flying the 747, and they had a total of 9,300 hours.

## The Collision

The two flights were flying over the Himalayas, as all flights should. The flights crossed paths, but ATC (Air Traffic Control) followed procedure and moved them 1,000 ft apart. KLM Flight 147 flew at 33,000 ft, and British Airways Flight 372 flew at 32,000 ft. The flights moved normally, until Flight 147 experienced something strange. The 737 banked hard to the right, and the pilots scrambled for answers. The plane soon entered a nosedive, and the pilots tried desperately to lift their plane back up. ATC told them to 'remain at 33,000 ft', as he could see they were losing altitude fast. And, seconds after beginning to fall, the worst happened. Flight 372 was now flying directly underneath Flight 147, and their flight was running smoothly. Then, the left wing of the now recovering Flight 147 sliced directly through Flight 372 at a 36° angle, resulting in a break-up of Flight 372.

The two pieces began to fall rapidly, but leading the way was Flight 147, which was now beginning to disintegrate because of it's rapid speeds. The nose section of the plane was observed to have created a sonic boom during it's decent, as it had exceeded the speed of sound. Nearby seismic recorders recognised the impacts of the aircraft, and was measured accordingly. Small impacts were heard first, and these were found to be the many parts of Flight 147 finally crashing into the ground. These were soon followed by two large impacts, and these being the front section of Flight 372, followed shortly by the back section.

## Aircraft State and Cause

When investigators arrived on the scene, they found the most intact area was the back of Fight 372, as it had not reached high speeds during it's decent. The second most intact area was of the front section, despite nosediving toward the ground. The least intact part was Flight 147, which was now buried beneath the wreckage of the 747. Around half a mile away from the crash site, some more wreckage was found. At first, it seemed unidentifiable, but after some hard work on the investigators side, it was found to be engine 2 of Flight 147. The fact that an engine and parts of the right wing being half a mile from the major crash site was extremely suspicious, and this eventually lead to the conclusion.

It was found that Flight 147's right engine came off and damaged the right wing. The damage plus the lack of engine created the harsh roll to the right, and also lead to the collision. The engine had come off due to metal fatigue taking place within the pylon of the engine (which keeps it on the plane), and the damage done to the wing was because the engine flew directly over the wing after coming loose. A similar (and real life incident) is El Al Flight 1862, which slammed into an apartment building in Amsterdam after engine 3 came loose and collided with engine 4.

## CVR Transcript

### KLM Flight 147

C - Captain Rochus Kuijpers

O - First Officer Gerlof Klaasen

S - System/Plane Alerts

A - Air Traffic Control

16:31:46 A - Incoming traffic at 12 o'clock.

16:31:54 C - KLM 147 copy.

16:32:01 O - It's quite a nice day today.

16:32:04 C - Yeah, specially because the sun isn't in my-

16:32:06 \*Clanking sound of engine coming off\*

16:32:08 O - The hell was tha- we're banking!

16:32:09 S - Bank angle, Bank angle (continues until 16:32:13)

16:32:09 C - Get it up!

16:32:11 O - We're flipping over!

16:32:13 S - Whoop Whoop! Terrain, terrain, pull up (continues until end of recording)

16:32:13 S - \*Further alarm sounds\*

16:32:14 A - KLM 147 remain at flight level 33.

16:32:15 C - Oh f\*\*k, we're gonna hit the other plane!

16:32:17 O - I'm getting it up!

16:32:19 C - S\*\*t, there it is!

16:32:20 \*Sound of impact with Flight 372\*

16:32:21 C - We hit it!

16:32:23 O - KLM 147 We've hit another plane!

16:32:25 O - Oh f\*\*k, the left wing's gone!

16:32:26 C - Oh god, we're gonna die!

16:32:28 \*Sound of the aircraft braking up\*

16:32:30 O - KLM 147 Mayday, Mayd-

\*Recording ends after mid-air breakup\*

#### ATC Recording:

16:32:30 O - KLM 147 Mayday, Mayday we've lost our wi-

16:32:31 \*Extremely loud sound, similar to an explosion. This was later found to be a sonic boom\*