CAA Safety Notice after Pilot ditched in Thames

Droider

Drone Enthusiast
All Please read the following bulletin

http://www.caa.co.uk/docs/33/SafetyNotice2013012.pdf

Dave

Civil Aviation Authority
SAFETY NOTICE Number: SN–2013/012
Small Unmanned Aircraft – Security of Antenna Mounts This Safety Notice contains recommendations regarding operational safety.
Recipients must ensure that this Notice is copied to all members of their staff who need to take appropriate action or who may have an interest in the information (including any ‘in-house’ or contracted maintenance organisations and relevant outside contractors).
Issued: 16 July 2013
Applicability:
Aerodromes:
Not primarily affected
Air Traffic:
Not primarily affected
Airspace:
Not primarily affected
Airworthiness:
Not primarily affected
Flight Operations:
All Small Unmanned Aircraft Operators
Licensed/Unlicensed Personnel:


Not primarily affected
1 Introduction
1.1 A recent incident involving a multi-rotor Small Unmanned Aircraft (SUA) occurred as a result of a combined GPS/compass antenna mount becoming dislodged. This resulted in erroneous readings and a loss of stabilised flight. The incident has highlighted the necessity of checking the secure attachment of all elements of an SUA during pre-flight checks.
1.2 The multi-rotor SUA was being used for an aerial work filming flight. During the flight the remote pilot noticed a decrease in stability and control. Coincident with this, he also noticed that the GPS/compass antenna had come loose and was wobbling on its mount. As part of the remedial actions/drills, the remote pilot switched control of the aircraft from GPS mode to ATTITUDE mode. However, it was clearly evident that stabilised flight could not be maintained and so the flight was terminated within a designated safe area.
1.3 The purpose of this Safety Notice is to highlight the requirement for the operator to be reasonably satisfied that the flight can be safely made (Air Navigation Order 2009 (ANO) Article 166(2)) and that all appropriate checks on the SUA are completed before take-off.
2 Causal Factors
2.1 The investigation concluded that the lack of security of the GPS/compass antenna mounting was the causal factor.
2.2 The remote pilot had completed his pre-flight checks including a visual inspection of the GPS/compass antenna, which was mounted on one of the rotor arms. The visual inspection
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Civil Aviation Authority Safety Notice Safety Notice SN–2013/012
had confirmed the correct orientation; however, the physical security of the mount on the rotor arm was not tested. With hindsight, the remote pilot noted that such a check would have confirmed whether or not the antenna mounting had been properly secured.
2.3 Because of the vibration that the rotor arm was subject to whilst in flight, the antenna mount became dislodged and therefore severely affected the quality of the information it was providing to the SUA’s stabilisation system.
3 Compliance/Action to be Taken
3.1 This Safety Notice recommends the following actions:
a) That the pre-flight checks should include a more rigorous inspection of any GPS/compass antenna mountings, including a physical check that they are securely fitted to the airframe.
b) That remote pilots regularly practise reversionary flight modes (where possible). Remote pilots should be competent with all emergency procedures such as loss of GPS.
c) That any detachable items (payload etc.) must be physically checked for security during the pre-flight checks.
4 Queries
4.1 Any queries or requests for further guidance as a result of this communication should be addressed to the following e-mail address: GA@caa.co.uk, with subject line ‘Safety Notice – SUA Security of Antenna Mounts’, or by post to the following address:
Flight Operations Inspectorate (General Aviation) Safety Regulation Group
Civil Aviation Authority
1W, Aviation House
Gatwick Airport (South) West Sussex
RH6 0YR
5 Cancellation
5.1 This Safety Notice shall remain in force until 31 July 2014.
 



swisser

Member
I received this notice too. Obviously the general advice is fine, but the most interesting part to me is this:

"As part of the remedial actions/drills, the remote pilot switched control of the aircraft from GPS mode to ATTITUDE mode. However, it was clearly evident that stabilised flight could not be maintained"

We know for sure that DJI systems, which I believe is what was being used (unless anyone knows differently?) don't need the GPS or compass in order to provide stable flight in ATTITUDE mode - witness the Naza which didn't have a Compass or GPS when it first came out and still in use by many people. So why didn't switching to attitude mode allow stabilised flight to be maintained? If it was a question of the pilot not being able to control the craft suitably that's fine, as it is if he was discombobulated by the goings on and took the preventative ditching measure. But if the CAA is suggesting that a loss of GPS/compass sensing capabilities is a reason for a forced landing, well, that seems wrong to me.
 

Blacksails

Member
Received this too. Do we know who it was? Glad to see we're all reporting incidents as they happen. Helps us all.

I'm guessing if the compass was flooping all over the place then the copter would have been spinning eratically. Keeping orientation for the few seconds this was happening before switching to atti mode would have be a difficult task. The pilot did the right thing dumping it if he couldn't quickly regain control

Alex
Expert model destroyer and aerial photographer!
 
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Benjamin Kenobi

Easy? You call that easy?
This was relating to the XFactor incident. There's a video on YouTube. They're remaining tight lipped about who was flying but the pilot was retested in April and passed with flying colours.
 

R_Lefebvre

Arducopter Developer
I received this notice too. Obviously the general advice is fine, but the most interesting part to me is this:

"As part of the remedial actions/drills, the remote pilot switched control of the aircraft from GPS mode to ATTITUDE mode. However, it was clearly evident that stabilised flight could not be maintained"

We know for sure that DJI systems, which I believe is what was being used (unless anyone knows differently?) don't need the GPS or compass in order to provide stable flight in ATTITUDE mode - witness the Naza which didn't have a Compass or GPS when it first came out and still in use by many people. So why didn't switching to attitude mode allow stabilised flight to be maintained? If it was a question of the pilot not being able to control the craft suitably that's fine, as it is if he was discombobulated by the goings on and took the preventative ditching measure. But if the CAA is suggesting that a loss of GPS/compass sensing capabilities is a reason for a forced landing, well, that seems wrong to me.

I was wondering the exact same thing. If the pilot lost orientation and couldn't regain it, I'd suggest he should sharpen up his manual flying skills, and/or employ navigation lighting to aid orientation. I successfully flew a 450 heli, 400m away in stabilize mode. It can be done.

If however, the loss of GPS and/or mag results in loss of pitch/roll stability, then I really wonder what's going on with that flight controller.
 

Kilby

Active Member
It was probably a Wookong, not a Naza. They have always had a GPS & compass and as far as I know, will not operate correctly without them, or if they become unmounted during flight. That was a pretty big MR, and if I had to bet, they were not controlling it with a Naza, which would only leave the Wookong as the culprit.

We know for sure that DJI systems, which I believe is what was being used (unless anyone knows differently?) don't need the GPS or compass in order to provide stable flight in ATTITUDE mode - witness the Naza which didn't have a Compass or GPS when it first came out and still in use by many people. So why didn't switching to attitude mode allow stabilised flight to be maintained? If it was a question of the pilot not being able to control the craft suitably that's fine, as it is if he was discombobulated by the goings on and took the preventative ditching measure. But if the CAA is suggesting that a loss of GPS/compass sensing capabilities is a reason for a forced landing, well, that seems wrong to me. [/COLOR]
 


swisser

Member
Kilby, I wasn't suggesting it was a Naza, I was suggesting that DJI's controllers work fine without compass and GPS and that is evidenced by the Naza. I have flown the WKM without too. Whilst I'd agree that odds on it was a WKM, just because it's a big MR that doesn't mean it couldn't be a Naza.
 

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