A320 Unusual windshield delamination

[Sheron]

This is an unusual one that happened to me a couple of days back. Took over an aircraft and pointed out the delamination of the windshield before my flight. Got the engineering to do their due diligence and they said the delamination was within limits and it was 50 mm limit was 70 mm. (unsure about it being mm or cm but I remember it to be within a margin of 20mm) I accepted the aircraft and off we went. The block time was just 01:05 flight time 00:50. When we were close to TOC which was FL290I noticed the delamination increasing and its contour and shape had changed and the delamination had extended and clearly had crossed in the 20 mm margin and was greater than 70 mm. Now her is the unusual part. Short sector asked for early descent and as we crossed around FL160 the delamination started to decrease but still over the limit. By the time we were on ground it came back to its dimensions that was there earlier. Reported to engineering,it was the first they heard of. They carried out a pressurisation check and nothing. Delamination did not change size or contour. Cleared the aircraft. I took the aircraft back again short sector same block and flight time and it happened again this time we saw a noticeable change from Fl240. Same thing when the diff pressure increased the delamination increased and after landing it went back to its original size and shape. Aircraft was a A320 CEO
Did anyone have a similar occurrence or can explain this. In my experience the delamination size and contour does not change with pressurisation.

[MechEngr]

I don't see why not - put on a load and deformations increase, particularly noticeable at a discontinuity. If it's all elastic then when the load is removed everything goes back.

The visible portion of delamination is the gap that has a different refractive index than surrounding material. If the gap closes then there is no longer a difference.

If it is replaced ensure they use the correct fasteners. No need for an open-cockpit flying experience.

[nonsense]

Bear in mind that pressurisation alone does not replicate all the loads on a windshield in flight; you're also forcing a lot of air out of the way of the aircraft. Quite possibly the effect in flight is a net positive pressure on the outside face of the windshield, since it's seeing something akin to the pressure at a pitot.

[Black Pudding]

And did you take pictures or a video of the event ?

[Sheron]

I got pics at various stages of climb and cruise and descent.

[Sheron]

Delamination usually remains constant or changes slowly but nonetheless after it has increased it never reduces. I have had delamination of windshield before and in 18 years of flying this the first one where I saw a delamination increased in size and contour change when pressurised and return back to its original length when back on ground.

[Jwscud]

We had a similar event on my fleet recently. Happened to a crew and they wrote it up on their return. Aircraft AOG for a windscreen change. I was meant to be taking it and the engineer said no sane engineer would sign it off as within limits given the description of the in flight event.