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DA62 G-MDME calibration flight down - Dubai

Peter wrote:

Yes, of course, if you start of a roll and take your time over it then you get a pitch-down, and it can easily be non-recoverable. I just thought that encountering a wingtip vortex produces such a high roll rate that there isn’t time to get much of a pitch-down.

One data point would be the 152 that I did a lot aerobatic instructing in, if you use full aileron at about 130kt without any initial nose up entry, it would be a about 10 degrees below the horizon, if you paused for second, or pulled harder on the stick by the time we went all way around I would guess an attitude of 45 degrees. This would just be observing a student who had already been briefed on what do… (the oil system of the152 is not capable of the classic slow roll)

Perhaps a better summary would be nose attitudes 45 degrees from where they were supposed to be during the initial phase of aerobatic training would not be uncommon.

Last Edited by Ted at 04 Jun 13:15
Ted
United Kingdom

Peter wrote:

What would cause the pitch-down?
The wake vortex should produce a roll, only.

As MattL said they are already pitch down on low power, I will add probably no height and slow/fast speed margins

I would assume if one fly the middle the green-white speed band (Vs, man(Vb,Va,Vfe)) without much power and some spare 2000ft agl height, good harnesses & visible horizon they may have more chances to get away from it, but surely not when you fly too slow or too fast at 500ft agl? aerobatic training experiences stops at 500agl everybody will tend to intentionally pull up the stick bellow that when they are caught by surprise…

Last Edited by Ibra at 04 Jun 12:11
Paris/Essex, France/UK, United Kingdom

Yes, of course, if you start of a roll and take your time over it then you get a pitch-down, and it can easily be non-recoverable. I just thought that encountering a wingtip vortex produces such a high roll rate that there isn’t time to get much of a pitch-down.

Administrator
Shoreham EGKA, United Kingdom

Peter wrote:

What would cause the pitch-down?

One advantage of some aerobatic training, are the following lessons, if your inverted or nearly so, you will need forward stick pressure to KEEP the nose above the horizon. In a barrel roll where you keep positive G, it is essential that the nose is already sufficiently above the horizon ON ENTRY as it will constantly trend towards the axis of the roll, that direction will be towards the ground while your inverted. The other is from an inverted position pulling back to complete a loop requires far more altitude and may exceed many V speeds, than rolling level again.

What the pitch moments are during inverted flight is probably better discussed in a separate thread

Last Edited by Ted at 04 Jun 12:02
Ted
United Kingdom

Any significant amount of roll will cause a pitch down/descent, especially from already nose down approach attitude

Posts are personal views only.
Oxfordshire, United Kingdom

What would cause the pitch-down?

The wake vortex should produce a roll, only.

Administrator
Shoreham EGKA, United Kingdom

Emir wrote:

These runways are too close to each other and the approach path should be considered as the same path for both runways.

Absolutely correct from a legal POV. The accident, however, has much to do with the mental picture and the risk assessment in the mind of the pilot. And for that one could at least imagine that it makes a difference if you hear that another plane is on the same or on a different approach – even though this difference is not justified by facts.

Germany

You can’t localise a vortex that easily even when you know the position of the heavy aircraft and the wind, the vortex path shown in the report using LIDAR is way different from the textbooks in terms of extent and rate of descent and in a calibration flight you just fly the calibration path no? so there is no mental picture of a tactical WT avoidance just a timing decisions?

Last Edited by Ibra at 04 Jun 08:08
Paris/Essex, France/UK, United Kingdom

When issuing warnings about wake turbulence, ATC does not and is not required to consider wind. But I would imagine that the commander in this case did just that, and maintained a mental picture of the path of the wake vortices. I cannot believe he dismissed the risk of flying into a vortex, I rather think he may have felt quite certain about its position – but made a mistake.

huv
EKRK, Denmark

172driver wrote:

I know nothing about the normal traffic flow into Dubai, but in most / all other large airports in the world, early evening is rush hour. As they were calibrating lights, might it not have made more sense to do these flights during some slow / dead time?

I think you will find that for most of the middle east that is the quiet time. Most flights are late night, early morning, until about midday.

Regards, SD..

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