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Police helicopter crashes onto Glasgow pub

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Police helicopter crashes onto Glasgow pub

Old 4th Jan 2014, 15:13
  #1621 (permalink)  
 
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And (does'nt matter in this case) hte fuel consumtion for a given task is in kilograms. If the SG is lower, there fuel consumption in liters will be higher. So, if calculated in kilograms theres no need to recalculate the fuel consumtion (in liters) depending on temperature.
Indeed, but what does matter is if someone, by mistake, adds 20% to the number in litres to get the kg instead of the other way round. The difference is very significant, and mistakes can happen. Not saying it did here, tho', no evidence that it did or didn't.
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Old 4th Jan 2014, 15:24
  #1622 (permalink)  

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But a mistake would show up on the fuel gauge in the cockpit.

Btw, all this semantic discussion about fuel related helicopter accidents.... The cause of this tragic one may not be fuel starvation.
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Old 4th Jan 2014, 15:57
  #1623 (permalink)  
 
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But a mistake would show up on the fuel gauge in the cockpit.

Btw, all this semantic discussion about fuel related helicopter accidents.... The cause of this tragic one may not be fuel starvation.
Agreed that there is as yet no evidence in our possession to suggest that the cause was fuel-related. Certainly something went wrong. The a/c wasn't intended to crash onto a city pub seemingly with no power being transmitted from the engines to the rotor.

Was the pilot incapacitated? Has not been stated either way.
Did the pilot make a flying mistake that he failed to rectify?
Was the aircraft wholly or partly un-flyable? (e.g. fuel, mechanical failure)
It is possible that the cause is included in all of the above.

For example, the pilot was under the influence of some substance and took off with less fuel than he thought. Concentrating on the mission, believing he had 'plenty' of fuel, he didn't focus on the fuel. When the fuel warning came on, some distance from base, he was taken by surprise and became disoriented, perhaps due to the drugs. The pilot commenced a manoeuvre in an uncoordinated manner losing altitude to the point that he considered that to land on the apparently safe black block below him was a safer strategy than recovery and return to base.

There is no evidence whatsoever to support that or rule it out....at least not evidence available to PPRuNe posters. Furthermore, it seems unlikely given the service record of the pilot. Until some other hard information comes to light, we haven't got anything more to go on.
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Old 4th Jan 2014, 16:22
  #1624 (permalink)  

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The semantics are getting more unlikely still. If the pilot had turned up for work in a situation where he was unfit, the two police observers who were in close proximity to him throughout might just have observed that something wasn't quite right.

Especially as they would no doubt have previously dealt with members of the public who were in that situation.
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Old 4th Jan 2014, 16:35
  #1625 (permalink)  
 
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ShyTalk -- You're probably right. I doubt it's the answer. But nothing so far makes too much sense because there has been no safety check on other a/c other than fuel instruments which look unconnected with this. Whatever happened IS extremely unlikely. If it was likely, then 'they' wouldn't have let the a/c fly!
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Old 4th Jan 2014, 16:39
  #1626 (permalink)  

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I noticed that nothing was mentioned in the AAIB preliminary report about the integrity of the fenestron, only that the main rotor gearbox was capable of driving the driveshaft.
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Old 4th Jan 2014, 16:46
  #1627 (permalink)  
 
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Fenestron intact?

From the clear photo in http://www.pprune.org/8244492-post1677.html the chances of it being in a pre-crash state don't look good. However, if I remember correctly, the AAIB statement did say that all components were found at the crash site.

There are photos online of substantial parts of an un-enshrouded, yet substantially complete, fenestron fan being hoisted away from the crash site: one is currently illustrating a charmless tale here: Glasgow Pub Crash: Teen Arrested for 'Sectarian' Comments [VIDEO]. Whether it landed in a working condition of course remains a question. Its hub being hoisted away substantially intact is perhaps consistent with it not turning on impact (as probably noted previously in the thread).

Last edited by awblain; 4th Jan 2014 at 21:25. Reason: Correction to link address & link to fenestron removal image
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Old 4th Jan 2014, 17:10
  #1628 (permalink)  
 
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If the tank was "brimmed", then the weight carried would be the tank maximum volume divided by the fuel density.

Multiplied not divided: 100L weighs ~81kg. Weight and balance is one of the first things a student pilot learns, before going cross country. But I do wonder how people can read that and apparently not notice.
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Old 4th Jan 2014, 17:37
  #1629 (permalink)  
 
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Oops, yes. Exactly the sort of error that needs to be avoided.

I shall edit my original post to show I did it wrong.
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Old 4th Jan 2014, 17:40
  #1630 (permalink)  

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Ornis - You sure about the 0.81? Your student won't get very far if he needed 100L AVGAS....

Ah, in retrospect I think you mean 100 litres ....but his aircraft is more likely to be non-turbine and need AVGAS, not Jet A1. So he would use 0.7 SG as his conversion factor.
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Old 4th Jan 2014, 17:45
  #1631 (permalink)  
 
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Probably no relevance but a picture has been found on Flickr with a good view of the roof of the pub in 2012. The tryst bar and the clutha bar Glasgow_ASN2235 where a police Helicopter - A Eurocopter EC135 T2 crashed | Flickr - Photo Sharing!
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Old 4th Jan 2014, 18:44
  #1632 (permalink)  
 
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One hundred litres is written 100L or 100l. Both are correct. I prefer "l" but I thought some helicopter pilot might read "l" as "1" and argue the point about 1001 bananas.

Or possibly go off on a tangent about avgas when the EC135 we have been discussing all this time uses JetA1 or whatever.

A pilot must see the crux of an issue or problem immediately and the problem I saw was a wrong conversion from volume to mass.

The fact is, quantity or capacity can be measure by volume or mass, both are correct. It's usual to buy fuel by volume and mandatory to flight plan by mass. The relationship is given by the specific gravity. We all know this.
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Old 4th Jan 2014, 18:52
  #1633 (permalink)  

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Yes, we do all know this. But incorrect conversion of litres to kilograms or vice versa is likely to be irrelevant to the cause of this accident, as per my earlier post.

BTW, in my tech log, I use the annotation "LTRS" for litres, to avoid any confusion.

Another possible gotcha is engine oil quantity. The oil contents (and maximum usage rates) are quoted in litres. The oil is packaged in US Quart cans.
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Old 4th Jan 2014, 18:58
  #1634 (permalink)  
 
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But conversion of litres to kilograms or vice versa is likely to be irrelevant to the cause of this accident.
But the crash was unlikely so the cause of the crash is going to an 'unlikely' event or combination of events.
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Old 4th Jan 2014, 19:09
  #1635 (permalink)  

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So it might be. Or then again, possibly not.

The circumstances are most unusual, possibly unprecedented. Certainly I know of no similar RW accident on a twin engined helicopter and I've been flying helicopters for a living for thirty five years.

The point is, there was fuel in the aircraft, that has been proven beyond doubt. although a relatively small quantity, it would normally have been enough to make a safe landing with. Not a stopped rotor "arrival", as this evidently was.
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Old 4th Jan 2014, 23:26
  #1636 (permalink)  

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A turbine engine flows much more air than is needed for combustion, unlike a piston engine burning AVGAS, where the ratio of air and fuel are more critical.
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Old 5th Jan 2014, 01:48
  #1637 (permalink)  

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The closest I can find on anything remotely similar.

NTSB Looks At Cranes In Potomac Crash | Aero-News Network
Press Release [January 12, 2005] - NTSB - National Transportation Safety Board
NYC05MA039
Full report

According to the flight nurse, after the helicopter flew over the southern half of the Woodrow Wilson Bridge, the next thing he recalled was being submerged in water with his seatbelt on and his helmet off. He stated that the helicopter's master caution lights and panel segment lights did not illuminate and that he did not hear any audio alarms sound before the crash. He stated that the pilot did not execute any evasive maneuvers or communicate any difficulties, either verbally or nonverbally.

According to witnesses in vehicles on the Woodrow Wilson Bridge, the helicopter crossed over the bridge before it descended and then impacted the water. None of the witnesses reported seeing the helicopter impact any objects before its descent. The wreckage was located in the Potomac River about 0.5 nm south of the Woodrow Wilson Bridge.

According to the DCA automated surface observing system, located about 3.5 nm north of the accident site, the reported conditions at 2251 were winds calm, visibility 10 statute miles, broken clouds at 13,000 feet and 20,000 feet, temperature 45 degrees Fahrenheit (F), dew point 36 degrees F, and altimeter setting 30.25 inches of mercury.

Wreckage was scattered along a north-south oriented debris path. The wreckage was recovered, and examination indicated no evidence of a collision with a bird or other object, fatigue fractures, or other anomalies.

The main rotor mast was in place and intact in the main transmission. The root ends of the four main rotor blades remained attached to the main rotor hub on the mast.

The main transmission remained attached to the center section of the upper airframe structure, and all four mounting points were intact. The main transmission turned freely, no chips were found on the detectors, and the transmission appeared intact and functional.

The tail boom was separated at the aft fuselage frame. The tail section included the complete fenestron assembly [11] with the tail rotor gearbox and tail rotor. The tail rotor driveshaft was displaced forward about 1.5 inches. The aft portion of the driveshaft, which was carbon composite, was found fractured, torsionally cracked, and deformed. All tail rotor blades remained complete and attached to the hub. The fenestron shroud around the tail rotor showed a rotational scrape at the 5 o'clock position. The width of the scrape corresponded with the tail rotor-blade width.

Both engines showed little damage, and the gas generator (N1 compressor and turbine) and power turbine (N2 turbine) for each engine rotated freely. Nonvolatile memory data extracted from the electronic engine control units for each engine revealed no evidence of preimpact faults.
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Old 5th Jan 2014, 13:27
  #1638 (permalink)  
 
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SS -- very similar, when you look for the similarities not the differences. I looked at the 'full' report and can't see what the cause was ruled to be.
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Old 5th Jan 2014, 14:53
  #1639 (permalink)  
 
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For the above referenced LifeNet EC-135 crash the NTSB concluded:

PROBABLE CAUSE
The National Transportation Safety Board determines that the probable cause of this accident was the pilotís failure to identify and arrest the helicopterís descent, which resulted in controlled flight into terrain. Contributing to the accident were the dark night conditions, limited outside visual references, and the lack of an operable radar altimeter in the helicopter.
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Old 5th Jan 2014, 15:21
  #1640 (permalink)  
 
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Shy? is there a significant difference between Us Quarts and Litres?
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