Engine Boost?

https://en.wikipedia.org/wiki/Munich_air_disaster

Boost surge...aka

https://en.wikipedia.org/wiki/Compressor_stall

Basically I think it's what happens when the turbo charger is producing more air than the engine can accept....

Likely this was caused by a lean fuel condition due to atmospheric density variability with no active fuel adjustment capability...

My understanding is that the compressor blades are airfoils, and if the airflow past these blades exceeds the maximum permissible angle of attack, they can stall just as an airplane wing can stall. This would happen if there was insufficient airflow through the compressor.

Thank you, a link from your link gave me the explanation.

"Since a supercharger is usually designed to produce a given amount of boost at high altitudes (where the air density is lower), the supercharger is often oversized for low altitude. To prevent excessive boost levels, it is important to monitor the intake manifold pressure at low altitude. As the aircraft climbs and the air density drops, the throttle can be progressively opened to obtain the maximum safe power level for a given altitude. The altitude at which the throttle reaches full open and the engine is still producing full rated power is known as the critical altitude. Above the critical altitude, engine power output will reduce as the supercharger can no longer fully compensate for the decreasing air density."

This shows me why pilots are concerned with the engine boost indicator on that plane. And what "boost" is.

Thank you.

Well any takeoff I've seen or done was always at full throttle...so if you're taking off the boost is not adjustable, or at least wouldn't be on the example in question, so without fuel adjustment being set for the air density, you might have this problem...of course modern planes have a fuel management system which can self adjust for conditions...

Well, depending on aircraft type and conditions, commercial jets very rarely, if ever, adjust thrust to max on takeoff.

GA aircraft I have flown in also do not select full throttle for takeoff, either. There is an rpm best suited to climbing, again depending on conditions.

I don't not claim to be an aviation "expert". This is based solely on personal observations.

Quoted from KP Schroer

Former Captain DC3, M404, YS11 (1981–1986)

..."I’ve flown large and small recips and turboprops. All takeoffs used max power when available. But not all used full throttle.

Mechanically supercharged engines, like the P&W R1830’s and R2800’s used on the DC3 and M404 could deliver much more than the maximum allowed manifold pressures at sea level. The throttles had to be carefully set so the limits weren’t exceeded.

Turbo-supercharged engines, like the Continental TSIO-520’s we had on the C402 had an automatic waste gate that regulated manifold pressure. So in those we used full throttle, but had to be careful not to advance them too rapidly to avoid overboost.

Small, normally aspirated engines on small planes like the Cessna 172 just use full throttle.

Turboprops that use the P&W PT-6 are like the mechanically supercharged recips. Power has to be carefully set to avoid over torqueing. In addition, exhaust gas temperature has to be watched because you may reach that limit before the desired torque is set.

Older turboprops like the Rolls Royce Dart did use full throttle for takeoff. But the “fuel trim” was set beforehand to avoid over temping."...

https://en.wikipedia.org/wiki/Airspeed_Ambassador

It looks like the engines on this plane would have been the Centaurus 661 version...

..."The Centaurus was produced in 34 variants, ranging from the 2,000 hp (1,500 kW) Centaurus I to the final 2,405 hp (1,793 kW) Centaurus 663 for the Airspeed Ambassador airliner. The most powerful variants to enter service were the 2,625 hp (1,957 kW) Centaurus 170, 173, 660, 661 and 662.^[6] "...

...."Thain told the station engineer, Bill Black, about the problem with the boost surging in the port engine, and Black suggested that since opening the throttle more slowly had not worked, the only option was to hold the plane overnight for retuning. Thain was anxious to stay on schedule and suggested opening the throttle even more slowly would suffice. This would mean that the plane would not achieve take-off velocity until further down the runway, but with the runway almost 2 kilometres (1.2 mi) long, he believed this would not be a problem. The passengers were called back to the plane 15 minutes after leaving it.^[29]

The pilots agreed to attempt take-off, but that they would watch the instruments for surging in the engines. At 15:03, they told the control tower of their decision.^[32]

1:14CC

Rayment moved the throttle forward slowly and released the brakes; the plane began to accelerate, and radio officer Bill Rodgers radioed the control tower with the message "Zulu Uniform rolling".^[33] The plane threw up slush as it gathered speed, and Thain called out the plane's velocity in 10-knot increments.^[33] At 85 knots, the port engine began to surge again, and he pulled back marginally on the port throttle before pushing it forward again.^[33] Once the plane reached 117 knots (217 km/h), he announced "V1", at which it was no longer safe to abort take-off, and Rayment listened for the call of "V2" (119 knots (220 km/h)), the minimum required to get off the ground.^[34] Thain expected the speed to rise, but it fluctuated around 117 knots before suddenly dropping to 112 knots (207 km/h), and then 105 knots (194 km/h).^[35] Rayment shouted, "Christ, we won't make it!",^[35] as Thain looked up to see what lay ahead.^[36] "....

https://en.wikipedia.org/wiki/Munich_air_disaster

https://en.wikipedia.org/wiki/Bristol_Centaurus

You know it sounds to me like the plane was too heavy for the conditions....You have to wonder if the plane would have made it with about a half dozen fewer people...In any case it seems to me that it's better to err on the side of safety in situations like this...

"The Munich air disaster occurred on 6 February 1958 when British European Airways Flight 609 crashed on its third attempt to take off from a slush-covered runway at Munich-Riem Airport in Munich, West Germany."

https://en.wikipedia.org/wiki/Munich_air_disaster

I suspect that the slush on the runway probably had a lot to do with it, increasing drag and reducing speed. The engines would be working harder with less air flowing into the superchargers.

It took so long to get up to speed......they got into the area of the runway where no planes had been that day and the slush was thick. They probably had been only clearing half the runway.