Originally Posted by Bell_ringer
(Post 10210987)
Dammit!
We fly on the other side of the road here, probably why everything is the other way round :} |
From the latest White Horse News freebie rag, which has just dropped through the letterbox.
". WILTSHIRE Air Ambulance’s helicopter is now able to resume flying operations. Following rigorous testing of the Bell 429 helicopter on the ground and in flight, it was released back to operational flying last month. The helicopter had been out of service since the evening of 15th June following an incident on the charity’s helipad at its airbase at Semington, near Melksham. The charity stated, “While the pilot was carrying out the prescribed daily engines’ power assurance checks, the helicopter suffered an event of uncommanded tail rotor input. During the procedure the helicopter performed two and a half, counter clockwise, uncommanded spins and came to its final stop following the prompt and appropriate actions of the pilot. No damage occurred to the aircraft, ground equipment or airbase. " Air ambulance returns to the skies | White Horse News |
If it's not one thing, it's another! This from the local police Faceache page - my bold
"Wiltshire Police 16 hrs · |
Originally Posted by Dai Whirlybird
(Post 10209067)
I hear that the WOG (wheels on ground switch) failed shortly after this airframe returned into service following the undemanded yaw incident - here's a question or two.....
Given that PAC (Power assurance check)s are done when light on the wheels, Is it feasible that the WOG micro-switch can cycle on and off in this configuration or is it isolated by software when conducting the PAC? The WOG switch undoubtedly feeds it's status into the ADIU (Aircraft Data Interface unit) so is it possible that a cycling WOG switch or an intermittent fault with it could create confusion within the ADIU and generate spurious control inputs? What I don't know is whether the AFCS / AP configuration when conducting a PAC will permit or prevent this. "The AP will perform a preflight self-test when the AP switch is turned ON The preflight test requires the following: The TRIM switch is ON The helicopter is on the ground (weight-on-gear ) Engine power is available and is set at low torque The other AP is not in the process of performing its self-test During the preflight test, the AP verifies its ability to manipulate the actuators. So there's a definite link between the WOG status and the AP testing the acuators. As stated I do not know what state the AP was in at the time, but (to my mind and based on the foregoing) there definitely seems to be potential for a faulty WOG switch to impact on the AP self test of the actuators. I guess, given the AAIB's lack of involvement that we'll never know. |
Originally Posted by Dai Whirlybird
(Post 10228246)
The TRIM switch is ON
The helicopter is on the ground (weight-on-gear ) Engine power is available and is set at low torque The other AP is not in the process of performing its self-test During the preflight test, the AP verifies its ability to manipulate the actuators. |
As stated I do not know what state the AP was in at the time, but (to my mind and based on the foregoing) there definitely seems to be potential for a faulty WOG switch to impact on the AP self test of the actuators. I don't want to seem PC but the acronym WOG has a distinctly 70's racist undertone and could be replaced by another term. |
Originally Posted by [email protected]
(Post 10228263)
only if the pilot was stupid enough to initiate the AP test in the middle of the PAC when light on the skids - unlikely!
I don't want to seem PC but the acronym WOG has a distinctly 70's racist undertone and could be replaced by another term. As for WOG being racist, don't be pathetic- it's all about context and we're talking about helicopters....For those who don't know it means WEIGHT ON GEAR as referenced throughout the FM....and that's not a radio frequency............. |
Very PC. You could always write wheels on ground in full everytime.
Most under 40s would not even notice. We older persons will truly die out. |
Originally Posted by [email protected]
(Post 10228263)
only if the pilot was stupid enough to initiate the AP test in the middle of the PAC when light on the skids - unlikely!
The thrust of my ramblings is that without independent oversight (AAIB) and due process, we (outsiders) will almost certainly never know what caused this aircraft to spin 2 1/2 times and end up 2-3 metres from the hangar door. You appear to be quite protective of the pilot, I know them and their background and wonder if they are one of your ex SAR colleagues? Please try and keep an open mind, we all admire loyalty. but similarly we're all capable of mistakes regardless of whether you're a pilot, a design engineer or a manufacturer of components. |
Crab, I disagree if the AP was initiated correctly but a faulty WOG switch prevented the self test from initiating it could then erroneously signal weight on gear at the wrong time and the AP could then initiate the self test at the wrong moment, the self test involving communication with the actuators. |
We older persons will truly die out. |
You appear to be quite protective of the pilot, I know them and their background and wonder if they are one of your ex SAR colleagues? Please try and keep an open mind, we all admire loyalty. but similarly we're all capable of mistakes regardless of whether you're a pilot, a design engineer or a manufacturer of components. |
Originally Posted by [email protected]
(Post 10228525)
yes, I do know the pilot concerned but you seem keen to point the finger in the direction of pilot error .
|
Key point here....it matters not "who" was involved.
What matters is "why" the Aircraft spun around several times.....and there is no definitive explanation and no apparent interest by the CAA or AAIB in seeing some sort of explanation to the occurrence. Why might that be I wonder? |
It looks like the AAIB did eventually get involved with Wiltshire Air Ambulance's 429 incident(s) and it has resulted in an EAD being issued a few days ago.
Clicky linky thing to the EAD. Their 429 is still AOG and they're continuing to lease a 902. |
Is there going to be a statement from the WAA director of aviation! |
Originally Posted by [email protected]
(Post 10228263)
I don't want to seem PC but the acronym WOG has a distinctly 70's racist undertone and could be replaced by another term.
|
Originally Posted by RMK
(Post 10471726)
Still not as bad as the ICAO codes for Nigeria Airways and Nigerian Air Force which are NGA and NGR respectively - that's just wrong.
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