Ooops....

[petermcleland]

The mooring line catching on power lines seems a very likely cause as it would cause that ever steepening dive...Perhaps the remedy would have been to apply full reverse thrust on all engines and jettison the mooring line if that is possible Easy to say that with hindsight! However, it may well mean that nothing is wrong with the ship at all

[Archer]

The video of it is very worrying . There appears to have been no pitch authority at all with the craft maintaining a steep nose down attitude which, if anything, steepened further in the last 20 or 30 feet of descent. This was in what appear to have been relatively calm conditions . Thank goodness the crew escaped unhurt - they were very very lucky

Bear in mind that at any pitch attitude other then level, you can get quite a bit of aerodynamic lift from a surface of that size with only a bit of forward movement. I'm not saying that that's what happened, but it would account for the increase in nose-down attitude. Craft like these also have quite a bit of momentum so they may have just set themselves up for a slow descent and misjudged the energy in that maneuver. These things really are like ships in that respect.

Then again, if this is a crash... as someone else said 'they could have completed the incident debrief before they actually hit'.

[Chris Trott]

The mooring line catching on power lines seems a very likely cause as it would cause that ever steepening dive...Perhaps the remedy would have been to apply full reverse thrust on all engines and jettison the mooring line if that is possible Easy to say that with hindsight! However, it may well mean that nothing is wrong with the ship at all

I'm pretty sure it wasn't the handling line. Here's the problems with the claim -

1) Handling lines are made of non-conductive material. If they were conductive, they'd build up a static charge and hold the static charge of the ship in them - bad thing for the first guy to touch them. On normal blimps and dirigibles, there's a separate conductive line dropped prior to landing that is used to discharge the build up. I don't think there's one on the AirLander since it normally lands itself without need of handling prior to touchdown.

2) The pictures of the airship just before impact show the handling line hanging freely.

3) The power lines that it "hit" are several hundred yards behind the impact point. That line is maybe 100 feet long.

4) There's no knot and maybe a little weight at the end, but usually it's enclosed within the line, so it's not really easy to snag on anything. Most of those problems were thought of many moons ago, usually because of something like that happening.

[petermcleland]

http://www.dailymail.co.uk/news/article ... l?ITO=1490

[airboatr]

That's not the only blimp that got clothes lined.

[Archer]

Always interesting to see how that particular publication manages to keep the suspense up in its articles. They keep repeating that something hit the powerline before the crash, it isn't until a lot later in the article that they quote the company clearly stating that the powerline was not involved in the crash. I think I'll await the official report.

[cstorey]

There is an interesting discussion ( not often that that happens!) on pprune in which one or two people who sound as though they know what they are talking about suggest that the craft was stalled( and possibly badly out of trim ) which explains why the nose down attitude could not be corrected . I had not realised that this is not really an airship but depends to a degree on aerodynamic lift

[Archer]

One of the guys on there is very closely involved with the programme. The latest press release from HAV is here: https://www.hybridairvehicles.com/news- ... ugust-2016

[Chris Trott]

The important part here -

There has been speculation in the media as to the cause of the heavy landing including a number of factually incorrect statements. Until the investigation is completed it is not appropriate to make statements beyond those we have previously made. These included a clarification that a mooring line attached to the Airlander did contact a power line outside the airfield, but that no damage was caused to the aircraft by this event and this contact with the power line did not contribute to the heavy landing.

(my emphasis)

I had suspected some sort of out-of-trim situation with how quickly the nose dove down, but hadn't thought about an aerodynamic stall causing it. I had thought that maybe there had been a problem with water ballast resulting in it being nose heavy and when power was reduced to land that this cause the nose to dive. It is interesting that an aerodynamic stall can result in this as well.