Tiger Moth at Netherthorpe - any comments?

[Pull what]

Summary:
The pilot and passenger were taking off for a pleasure flight in the local area. The aircraft had full fuel and was just below its Maximum Takeoff Weight (MTOW). After lift off, the pilot found that he was unable to climb out of ground effect and decided to land in a field of crops. During the subsequent landing, the aircraft flipped inverted. The pilot believes that a slight reduction in available power, coupled with calm wind conditions and the short runways at Netherthorpe, contributed to the accident.



https://assets.digital.cabinet-office.gov.uk/media/559e218240f0b61564000033/De_Havilland_DH82A_Tiger_Moth_G-BYTN_07-15.pdf

When you read this accident, note, 'pleasure flying', 'aerial work', anything not seem quite right to you?

The Air Accidents Investigation Branch investigates civil aircraft accidents and serious incidents within the UK, its overseas territories and crown dependencies.

Our purpose is to improve aviation safety globally by determining the causes of air accidents and serious incidents, and making safety recommendations intended to prevent recurrence. It is not to apportion blame or liability.

Can anyone see any safety recommendations to prevent recurrence?

[Genghis the Engineer]

It's a commercial operation, so should have scheduled performance somewhere? Some years ago CAA made me re-do take-off, landing and climb/glide tests and provide a performance supplement for the POH in a similar period aeroplane when it went into public transport use certainly.

A 1000 hrs, probably quite young and sharp, very current pilot - albeit not with many hours on type, but enough that he should have known what he was doing.

This shows a TORR of 300ft, but not a TODR, but it's a reasonable working principle to double TORR to get a first stab of TODR, so 600ft.

http://www.harvards.com/wp-content/uploads/2014/12/Tiger-Moth-Pilots-Notes.pdf

Any qualified pilot knows how to do performance calculations.

Netherthorpe has 490m grass TODA on 24.

600ft = 183m.

x 1.2 grass factor
x 1.3 safety factor

(http://www.caa.co.uk/docs/33/20130121SSL07.pdf)

= 285m


So he should have had plenty to play with -


Obvious recommendations might involve a check on the performance of vintage aeroplanes being used for pleasure flights.

G

[Pull what]

Is it public transport though? They mention pleasure flying which Ive always understood to be public transport which needs an AOC and an Ops Manual and Training manual as a minimum with the additions you suggest but its 1.33

But the report says its aerial work-so it would need a pilot with an instructor certificate/rating surely if its an air experience flight and is being advertised as such.

The passenger and pilot would need weighing for public transport-how did he work out he was just below max take off weight,a guess or a calculation, the report doesnt state.

The report mentions he was taking off from the numbers on some take offs so he was loosing 120 metres of displaced threshold which was part of the TORA

[Genghis the Engineer]

But, losing 120m, and using a 1.33 factor - he should still have had enough runway.

So, still, the aircraft performance was inadequate, and arguably that should have been trapped by monitoring and maintenance procedures. In fact, as the Tiger Moth is Annex II, there should have been air test records to check that against.

G

[JammedStab]

It is difficult to form an opinion on this accident as there is a lot of important information that the AAIB has decided not to include in the report.

Pilot experience on type would be nice to know. Airport, elevation, altimeter setting and temperature(or just density altitude) would be extremely helpful.

No reason is given for the pilots opinion that there was a slight reduction in power. I believe there can be a climb or cruise prop installed on the DH.82.

While there is a significant runway upslope, he was already airborne but at a very slow speed. There were undulations that got him initially airborne on the edge of the stall. Was there an obstacle at the end of the runway that made him ease back on the stick and try to climb instead of accelerating in ground effect. Buildings and hedgerows are mentioned as nearby.

A lot of info that is unknown but the plane should have been able to climb away if operating normally. Unless there really is something about the engine, then it would likely be something to do with pilot technique.

Responding to the post below. Nitpicking over the name of report or bulletin is useless.
This bulletin has significant useful info missing that could easily have bee put in it.

I do do appreciate the Brits investigating this but once again, what other countries do is meaningless to this discussion.

10 hours is not a lot of time but not insignificant.

This takeoff may have been very different from the previous ones and mishandled.

[what next]

...that the AAIB has decided not to include in the report. It's only a bulletin, not a report.

Pilot experience on type would be nice to know10 hours it says in that bulletin.

A lot of info that is unknown but the plane should have been able to climb away if operating normally. Unless there really is something about the engine, then it would likely be something to do with pilot technique. Maybe, but the same pilot had made several flights with the same aircraft from the same runway earlier that day - again according to the bulletin. Why should he have changed his "pilot technique" between those flights?

There is simply not enough information to come to a conclusion. I don't know about the UK, but in many other countries there will be no further investigation when nobody was harmed in the accident. So more details may never be revealed.

[ShyTorque]

Other similar mishaps, same airfield:

ASN Aircraft accident 09-NOV-2002 Piper PA-38-112 Tomahawk G-BTOD (http://aviation-safety.net/wikibase/wiki.php?id=174013)

https://www.gov.uk/aaib-reports/piper-pa-28-140-cherokee-g-azwe-31-august-2005

https://www.gov.uk/aaib-reports/piper-pa-28-140-cherokee-g-zang-22-october-2011

Light aircraft crash at Netherthorpe - Gainsborough Standard (http://www.gainsboroughstandard.co.uk/news/local/light-aircraft-crash-at-netherthorpe-1-4633064)

[JammedStab]

It's only a bulletin, not a report.

One would think that it would be fairly easy to include weather conditions in a bulletin.

10 hours it says in that bulletin.

While not a particularly large amount of flying experience on type, by this time one should be getting more familiar with it.

Maybe, but the same pilot had made several flights with the same aircraft from the same runway earlier that day - again according to the bulletin. Why should he have changed his "pilot technique" between those flights?.

[/QUOTE]

Any experienced pilot will inform you that "techniques" may need to change between flights as conditions change. Of course, the classic example may be in this case where an underpowered aircraft is near MTOW on what appears to be a relatively short runway. On earlier flights he wasn't as heavy. I suspect that there is a good chance that being later in the day, there was an increase in temperature as well but that may not be the case.

Not adjusting your technique can lead to an accident.

The report does state..."The aircraft then struck an undulation and briefly became airborne but, despite the pilot’s attempt to stay airborne,
it touched down again. He tried again, aware that he had used about 250 metres of the runway compared with some 175 metres on previous takeoffs. Conscious of the extra weight, he briefly allowed the aircraft to stay in ground effect in order to accelerate, before raising the nose to climb away. At this point, the pilot felt that there was a general lack of energy and the climb rate reduced. He glanced at the airspeed indicator and recalls it reading 36-37 kt, so he lowered the nose to try and regain some energy, but this inevitably caused the aircraft to sink. "

Looks like an attempt was made to fly when too slow. Accelerating longer in the ground effect can help. I am curious what obstacles are at both runway ends. The winds were calm and he chose a 1.9% upslope. I would assume that was due to obstacles in the other direction.

[JammedStab]

https://www.youtube.com/watch?v=A5_o8qC7goA

Video shown here. Obstacles are not too bad.

[Mach Jump]

I think that the considerable upslope in the first 2/3 of RWY 24 not only lengthens the TOR, but, after getting airborne, can give the distinct impression that the aircraft isn't climbing, when, in fact, the ground is just rising beneath it.

This, particularly in a heavy aircraft, can lead to a nose high attitude, and an excursion up the back of the drag curve.


MJ:ok:

[Dusty_B]

He also had anecdotal evidence that the Tiger Moth’s Gipsy engine was prone
to a reduction of available power when operating continually over a lengthy period, due to heat build-up

Whether true or not, the engine had not been 'operating continually' in this instance, as it had just been refuelled - there was a good 20 mins between landing and taxiing out again.

One would think that it would be fairly easy to include weather conditions in a bulletin.

Only if the pilot report includes it, and then it is just the pilot's opinion/submission. A full investigation may look at getting an aftercast from the Met Office, or actuals from an official source. There was no one manning the 'tower' at Nethers that day; an observation was made approx 5 mins after the accident, but if the records weren't asked for (again, the only information source quoted was 'pilot report'), then they won't be reported.

[deefer dog]

This wasn't the first "it won't climb" Tiger incident, and probably won't be the last. Sure density altitude might have been a contributing factor, but I'll bet my next wage packet that the fuel selector was not FULLY open.

There isn't a lot of excess power available when flying a heavy Tiger Moth, and if there is even a tiny restriction in the fuel line this is exactly what happens. Seen it, and done it myself.