Did I witness an engine test for a 757 at MAN?

Question

A while ago (Summer 2020) I was walking near MAN airport (UK) and saw a 757 taking off. There was a peculiar event during takeoff and I'd love to know what it was.

Once airborne at about 1000 feet (complete guess) its starboard engine started showing flashing rings of flames and there was a loud repeating banging sound for about 20-30 seconds. The plane continued to climb up to several thousand feet.

While watching this I opened FlightRadar and saw that the flight's destination was also MAN.

Over the next 30 minutes or so the plane did a few laps and presumably came back to land.

I'd love to know what this event might have been?

score 29 · Accepted Answer · edited Nov 06 '20 at 12:29

29

See this avherald report: https://avherald.com/h?article=4db1ccdb&opt=1

A Jet2.com Boeing 757-200, registration G-LSAN performing a test flight from Manchester,EN to Manchester,EN (UK), was in the initial climb out of Manchester's runway 05L when the right hand engine (RB211) emitted a loud bang and streaks of flame. The aircraft levelled off at 5000 feet and returned to Manchester for a safe landing on runway 05R about 25 minutes after departure.

So yes, it was a test flight, but it obviously did not go according to plan, resulting in an engine failure.

edited Nov 06 '20 at 12:29

Federico

32,559
17
136
184

answered Nov 06 '20 at 12:02

Sanchises

13,247
3
49
82

4

It seems it tested things they weren't planning on testing. – FreeMan Nov 06 '20 at 12:41
1

Thanks very much, nice resource at AV Herald – JamesG Nov 06 '20 at 16:02
10

@FreeMan "We're returning to the airport" - "So the engine vibrations have stopped?" - "In a way..." – Sanchises Nov 06 '20 at 16:10
5

That's classic bird strike. – John K Nov 06 '20 at 16:55
@JohnK Indeed, that's what I thought too... – J... Nov 06 '20 at 22:15
2

@JohnK Given that it was a test flight, I wouldn't be surprised if it was an internal fault causing a compressor stall rather than an external cause. It's not uncommon for repairs to introduce new faults or not adequately address the initial fault - that's why they do the test flight. – Sanchises Nov 07 '20 at 07:44

reirab · Answer 2 · 2020-11-07T00:37:15.960

What you describe sounds exactly like compressor surges following an engine failure of some sort (e.g. a bird strike during takeoff.)

Here's a video of exactly that happening with a 757 at Manchester (though back in 2007, not this year):

In short, this is the result when something (such as damage to the engine) causes abnormal airflow through the engine. When a compressor's blades stall aerodynamically, the back pressure from combustion can literally cause the engine to backfire (i.e. blow air and combustion products out the front.) This relieves the overpressure in the engine, however, if the issue that originally caused the compressor stall isn't resolved, the pressure will build up in the combustion chamber in excess of what the compressor is able to blow backwards again and the cycle repeats until either the issue causing the stall is resolved or the engine is shut down.

For a much more in-depth discussion of this process, I'd recommending reading mins' answer to the question If the intake of a running jet engine is blocked for some short duration what would be the sequence of events following it?

Did I witness an engine test for a 757 at MAN?

2 Answers2