Go Back  PPRuNe Forums > Non-Airline Forums > Private Flying
Reload this Page >

Wycombe air park - accident

Wikiposts
Search
Private Flying LAA/BMAA/BGA/BPA The sheer pleasure of flight.

Wycombe air park - accident

Thread Tools
 
Search this Thread
 
Old 14th Jun 2011, 15:38
  #121 (permalink)  
 
Join Date: Mar 2011
Location: Essex UK
Posts: 186
Likes: 0
Received 0 Likes on 0 Posts
Never ! Not say that you or anyone on this forum does this, but with over 95% of all accidents due to pilot error, this accident chain of events is simply inexcusable.
Ever done a W&B calculation for a C 152 for a typical instructor and porky student with enough fuel for a typical 2hr PPL nav flight?

The fact this sort of practice does go on. The fact that people usually get away with it makes it to them 'acceptable'. The problem happens when as covered above, the grass is too long, the density altitude is high, the pilot skills are rusty, the engine isn't producing full power.. or more than likely one or more of the factors combine.

The fact it does go on is confirmed by simply reading the AAIB reports each year. There is always at least one of these accidents in the UK. I would rather guess that for countries where light aircraft are used far more for utility the figures are far worse. Strangely in many reports the overweight condition is mentioned but not even considered a contributing factor!
Conventional Gear is offline  
Old 14th Jun 2011, 15:41
  #122 (permalink)  
 
Join Date: Jul 2010
Location: USA
Posts: 563
Likes: 0
Received 0 Likes on 0 Posts
Could also be a half-engaged parking brake.
I've seen those before.
soaringhigh650 is offline  
Old 14th Jun 2011, 15:43
  #123 (permalink)  
 
Join Date: Jun 2003
Location: EuroGA.org
Posts: 13,787
Likes: 0
Received 0 Likes on 0 Posts
With an instructor present, nobody is going to question the w&b or the fuel endurance.

I used to do flights in my PPL training which I would have never done alone, and the intention was to fold my arms and let the instructor land it in some field if we ran out of juice.

We never did run out of juice, because the instructors knew exactly how far they could push it.

But a typical renter won't.
IO540 is offline  
Old 14th Jun 2011, 17:34
  #124 (permalink)  
Final 3 Greens
Guest
 
Posts: n/a
It is also wise to remember that the performance charts are for a new aircraft.

I remember calculating 4 up, 2 guys, one 8st guy, one 3 stone child and fuel to the tabs on a PA28.

The acceleration was awful compared to 2 up and I rejected the take off when we passed an intersection where I would have expected to be well airborne and we were pushing 55kts.

I'd only about 100 hours at the time and I was cursing myself all the way back to the clubhouse for having screwed up the W&B, even the tower asked if we were alright as they saw how long the roll was, I think they suspected a major engine problem.

The club owner was waiting for me when we got back and we ran through the W&B together, 50lbs under max, just like I'd calculated.

He was a decent guy and refused to charge me a penny, saying if it didn't feel right, best to chuck it away and stop.

A while later, the engine suffered a major failure.

I wil never know whether I saw the first symptoms of the impending failure or whether the old engine just could not deliver enough power anymore.

Makes you think.
 
Old 14th Jun 2011, 21:44
  #125 (permalink)  
 
Join Date: Aug 2002
Location: Italy
Posts: 368
Likes: 0
Received 0 Likes on 0 Posts
I think everything has been said.

- Habit, taken off before fully loaded, will manage this time too
- Performance figures are for new aeroplanes, most times we fly old clapped out engines.
- Pilot proficiency from short fields, and ability to judge grass length, also taking in to account if wet

For British pilots temprature and density altitude maybe a major unconsidered factor.

Flying in central Italy my aircraft performance changes considarably depending if I'm taking off sea level or from a strip in the Appenines, and even more so if in winter or summer.

In summer with 30° plus temprature I simply double take off roll if at sea level.

If in the mountains when hot I refer to the POH charts, consider full load even if light and add 20% scare factor. And even so, sometimes I scare myself.
AfricanEagle is offline  
Old 15th Jun 2011, 13:02
  #126 (permalink)  
 
Join Date: Jan 2009
Location: Great Missenden
Age: 41
Posts: 48
Likes: 0
Received 0 Likes on 0 Posts
Hey guys - some fuel for debate as you're all talking about weight and balance...

I read about this crash in the paper and the passenger was quoted as saying:

“The mechanical failure was unpredictable and I am sure in time when the results of the AAIB are published there will be some valuable lessons learned.”
sprthompson is offline  
Old 15th Jun 2011, 13:21
  #127 (permalink)  
 
Join Date: Sep 2003
Location: UK,Twighlight Zone
Posts: 0
Likes: 0
Received 0 Likes on 0 Posts
I look forward to reading about the nature of t he mechanical failure.....
S-Works is offline  
Old 15th Jun 2011, 13:28
  #128 (permalink)  
 
Join Date: Mar 2011
Location: Essex UK
Posts: 186
Likes: 0
Received 0 Likes on 0 Posts
For British pilots temprature and density altitude maybe a major unconsidered factor.
I think so to. Perhaps a twist of fate that a hot weekend in the UK is such a rare thing that many people load up the plane to head off.. It's certainly a factor I've only really begun to appreciate flying lower powered aircraft where on a hot day the climb rate is noticeably degraded.

I think the question of mechanical failure will make the AAIB report interesting. In the meantime if one flips back a few pages I think it is pretty clear people are discussing the issue of weight & balance in a general way.
Conventional Gear is offline  
Old 15th Jun 2011, 13:55
  #129 (permalink)  
 
Join Date: Jun 2003
Location: EuroGA.org
Posts: 13,787
Likes: 0
Received 0 Likes on 0 Posts
sometimes gear in transit is draggier than gear down.
There are very few (any?) piston GA types for which this is true.

The reason is that the gear doors are very simple, are usually only partial, and the parts which are presented to the airflow do not change in cross-section during the gear transition.

What you can get is a bit of yaw, during gear extension prior to landing, caused by gear on one side moving before the gear on the other side. This is common.
IO540 is offline  
Old 15th Jun 2011, 21:23
  #130 (permalink)  
 
Join Date: Jun 2002
Location: UK
Posts: 626
Likes: 0
Received 0 Likes on 0 Posts
"I look forward to reading about the nature of t he mechanical failure....."

Scales and calculator failures....?
smarthawke is offline  
Old 15th Jun 2011, 21:23
  #131 (permalink)  
 
Join Date: Sep 2006
Location: 23, Railway Cuttings, East Cheam
Age: 68
Posts: 3,115
Likes: 0
Received 0 Likes on 0 Posts
It is also wise to remember that the performance charts are for a new aircraft.

I remember calculating 4 up, 2 guys, one 8st guy, one 3 stone child and fuel to the tabs on a PA28.

The acceleration was awful compared to 2 up and I rejected the take off when we passed an intersection where I would have expected to be well airborne and we were pushing 55kts.

I'd only about 100 hours at the time and I was cursing myself all the way back to the clubhouse for having screwed up the W&B, even the tower asked if we were alright as they saw how long the roll was, I think they suspected a major engine problem.
Funny that, bearing in mind I'm an incredibly novice power flyer I always find our club 28 painfully slow to get off the ground compared to the 172's, you could read a book waiting for the ASI to creep up. It doesn't accelerate to rotation speed it 'proceeds'.

I asked one of our instructors about this and he said it's because the 28 is a heavier a/c but looking at the figures there's hardly anything in the weight between it and a 172. Same hp and everything. It also seems to take ages to accelerate to cruise speed at top of climb. I would be reluctant at my stage of the game, in fact I probably wouldn't at all, take a 28 into a smallish grass strip whereas it wouldn't bother me in a 172.

It is very nice to fly once it gets its breath back.

Last edited by thing; 15th Jun 2011 at 21:35.
thing is offline  
Old 19th Jun 2011, 19:59
  #132 (permalink)  
 
Join Date: Oct 2008
Location: Bussum
Age: 58
Posts: 2
Likes: 0
Received 0 Likes on 0 Posts
AAIB

I was called app. a week ago. I just told them what I saw.

They did not give any indication about the crash which I consider to be professional since the accident is still under investigation.
folberts is offline  
Old 20th Jun 2011, 08:29
  #133 (permalink)  
 
Join Date: Jan 2008
Location: London
Age: 68
Posts: 1,269
Likes: 0
Received 0 Likes on 0 Posts
Well done Folbert for speaking to the AAIB.

Did you see only the crash or also the run up ?

Last edited by vanHorck; 20th Jun 2011 at 08:46. Reason: correction as suggested by JW411
vanHorck is offline  
Old 20th Jun 2011, 08:42
  #134 (permalink)  
 
Join Date: Oct 2001
Location: UK
Age: 83
Posts: 3,788
Likes: 0
Received 3 Likes on 3 Posts
He did not speak to the CAA. He spoke to the AAIB (Air Accidents Investigation Branch).
JW411 is offline  
Old 13th Jul 2011, 20:56
  #135 (permalink)  
 
Join Date: Jul 2011
Location: Surrey
Age: 86
Posts: 1
Likes: 0
Received 0 Likes on 0 Posts
I have been following this thread with interest ... especially as I witnessed the incident.

As an old, low hours JAR PPL, I was waiting for the return of a WAC a/c for my booked slot at 13:45 on 3rd June. I was watching the activity on the apron, the arrivals and departures and listening in on 126.55. I watched the two visiting a/c being loaded for their trip to IOM, watched them taxi to the 06 hold.

The first a/c took off perfectly doing a good climb out on the NA turn to 03 and then onto a N departure. Soon after the Lance was cleared FTO ... watched it gain speed, it appeared to rotate soon after (on my eyeline from outside WAC to the tower in the range to the north of the airfield) 2/3rd's along the hard runway. It never reached higher than the windsock height and was obviously not going to get airborne ... wallowing and mushing, with no more than two pitch oscillation cycles. The pilot did not attempt any turn although the port wing was probable low as it impacted the hedge. The rest of the subsequent gyration of the fuselage was out of my view.

However, as Jon's excellent photographs show, the subsequent flip and slide were relativley short due to the inertia absorbing effect of the hedge which was sufficient to deccelerate the fuselage. However, I feel the significance of the post protruding from the undersurface of the fuselage (wap8.jpg) suggests that the post was picked up by entering the nose-wheel well destroying the starboard side of the nose-gear and impacting the firewall, flipping the fuselage ... rolling and yawing it to the right ... rather like a polevaulter rises using the pole to go over the bar.

This would have taken a lot more of the remaining intertia out of the Lance's progress across the field towards the M 40. The distance from the end of 06's asphalt to the M 40, as measured using Google Earth is 600 ft ... so had the aircraft not hit the hedge, the accident would have been far worse ... the M 40 Northbound gets busy on a Friday afternoon and its proximity to the incident can be assessed by the lamp-posts clearly seen in some of the images.

The incident certainly must have been a salutary lesson for any flyer who saw it happen. It was a mercy that there was no fire. Having seen two accidents in the past ... resulting in horrific conflagrations ... the Invadar flown by Don Bullock at Biggin and the Lighning, claiming the life of "Hoof" Proudfoot at Duxford ... it was such a relief to see all five walking through the gap in the hedge.

I need to get back into the LHS ... soon ... but glad I missed my slot that day!
Hiwyflr is offline  
Old 10th Mar 2012, 21:21
  #136 (permalink)  
 
Join Date: Jun 2002
Location: UK
Posts: 626
Likes: 0
Received 0 Likes on 0 Posts
AAIB report:

G-RHHT

I keep reading it but haven't spotted the aircraft's mechanical failure yet....
smarthawke is offline  
Old 10th Mar 2012, 22:47
  #137 (permalink)  
Moderator
 
Join Date: Feb 2000
Location: UK
Posts: 14,224
Received 49 Likes on 25 Posts
Originally Posted by smarthawke
AAIB report:

G-RHHT

I keep reading it but haven't spotted the aircraft's mechanical failure yet....
No, me neither. Although the bit about being 3.3" behind the aft CG limit and 186lb over MTOW seem clear enough.

Originally Posted by AAIB
The pilot stated that he did not have access to the actual passenger and baggage weights and therefore assumed values for his weight and balance calculation.
Hmmmm. I've never found it all that hard to ask my pax what they weigh and use us a cheap luggage balance to check bag weights.

There was also the point about the runway being several hundred metres too short if correct numbers and safety factors were used. I notice however that the AAIB didn't actually state (although it's easy enough to work out) that using the CORRECT weight, and the correct safety factors, the runway was about 240m too short. (Whilst still being 3.3" out of aft CG!).

Ho hum, I'm glad it's not me who has to explain that one to their insurance company.

G
Genghis the Engineer is offline  
Old 11th Mar 2012, 07:44
  #138 (permalink)  
 
Join Date: Dec 2011
Posts: 2,460
Likes: 0
Received 0 Likes on 0 Posts
186lb is quite a lot. Were the passengers all female by any chance?
peterh337 is offline  
Old 11th Mar 2012, 07:57
  #139 (permalink)  
 
Join Date: Sep 2003
Location: UK,Twighlight Zone
Posts: 0
Likes: 0
Received 0 Likes on 0 Posts
Just as I said. It did not take rocket scientist to work out it was overweight. I flew and taught enough in that aircraft to recognise it.
S-Works is offline  
Old 11th Mar 2012, 08:08
  #140 (permalink)  
 
Join Date: Dec 2007
Location: France
Posts: 481
Likes: 0
Received 0 Likes on 0 Posts
Genghis,

You wrote:

I notice however that the AAIB didn't actually state (although it's easy enough to work out) that using the CORRECT weight, and the correct safety factors, the runway was about 240m too short. (Whilst still being 3.3" out of aft CG!).
I presume this would involve extrapolation beyond the limits of the performance information in the manual, which some manufacturers get very upset about, and which may indeed be invalid.

A purist might argue that the CofG being out of limit would also invalidate use of the data, whether within or without the graphs or tables.

Finally, there might be the effect on a reader. Faced with an accident report which included reference to performance calculations for a weight over MTOW, he might believe there was something justifiable in flying overweight as long as the data was extrapolated to show that the runway was long enough...
frontlefthamster is offline  


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.