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1. 03:01 PM - Re: Static Events On Composite Airplanes (Peter Pengilly)
2. 04:33 PM - Re: Static Events On Composite Airplanes (Sebastien)
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| Subject: | Static Events On Composite Airplanes |
Hello Sebastien,
All I can offer is that we searched the accident databases to find out
what had been reported. If instances such as yours don=99t get
reported then nothing will get done until there is a nasty accident. Any
decent safety management system seeks to collect
=9Cnear-miss=9D data as a predictor of where accidents might
happen, it is disappointing GA doesn=99t do that.
Many homebuilders don=99t understand how their aircraft could fail
and put far too much trust in the promises of electronics salesmen. The
UK CAA forced us to assess each individual aircraft applying for an IMC
clearance to look at the power architecture of the instrument system.
Several have had to make changes to increase the robustness/resilience
or to look at what loads must be shed if the alternator fails. We have
no requirements for static build-up protection.
Peter
From: owner-aeroelectric-list-server@matronics.com
<owner-aeroelectric-list-server@matronics.com> On Behalf Of Sebastien
Sent: 06 March 2022 01:31
Subject: Re: AeroElectric-List: Static Events On Composite Airplanes
Hello Peter,
Like I said, I have no data. I included the anecdotes specifically
because I'm not sure that "We found no similar instances to yours when
we searched the accident/incident reports" is data either. An incident
which takes out half of the aircraft avionics and requires a diversion
to a nearby VMC airport would not show up in any accident database that
I am aware of. No one was injured and the aircraft did not suffer any
damage after the initial event. Both my incidents were in uncontrolled
airspace so definitely no report there. A friend of mine lost all
avionics except for a radio and the turn co-ordinator in an IMC static
event over the rocky mountains and required a great deal of help from
controllers to safely get the aircraft on the ground. Again, no database
that I know of contains this incident and it only happened 15 years ago.
Instrument failures happen for many reasons and when training IFR I go
to great lengths to make sure my students are as prepared as possible
for them but we rarely simulate losing most of the instrument panel. The
closest we get to that scenario is an alternator failure that eventually
leaves us on backup battery power for the approach.
These days I regularly see newly built amateur built that are IFR
capable. Many of these are built by pilots who have no IMC experience.
Sometimes the builder has given some thought to fault tolerance, other
times not. I have yet to see one where the builder gave any thought to
static problems, so I share my anecdotes and my caution to encourage
builders to think about the possibilities. All flying is risky to some
degree so I suppose my statement isn't very useful. I'm just trying to
point out the increase in risk.
On Sat, Mar 5, 2022 at 1:01 AM Peter Pengilly <Peter@sportingaero.com
<mailto:Peter@sportingaero.com> > wrote:
Dear Bill & Sebastien,
* flying IMC with a composite amateur built aircraft is risky
I really disagree with this statement. I also really disagree that the
certification rules are particularly relevant as they are designed to
mainly address lightning strike. It is worth looking at the data that is
available.
Some years ago I undertook an investigation for the UK homebuilt
association into IMC & night flying for homebuilts as UK homebuilts were
limited to day VFR. The conclusion was the risk of lightning strike on
single engined aircraft in IMC is so small it is not worth worrying
about. The risk of lightning strike in VMC was already accepted (and is
also very small). From the accident data for 40 years of flying in the
UK and 10 years in the US there was only one instance of a single
engined aircraft flying in IMC being hit by lightning, a 210 in the
eastern US, and that ended with a diversion and safe landing. For
whatever reason single engined aircraft are not hit by lightning. I do
completely agree that the thunderstorm is much more likely to kill you
than being hit by lightning! In the period we looked at around 60
aircraft, flying in IMC, came to grief because of flying into a
thunderstorm.
I have no experience of the effects of static discharge. We found no
similar instances to yours when we searched the accident/incident
reports, but that was 10 years ago and the number of EFIS equipped
aircraft has increased considerably in the intervening years. However,
EFIS (or solid state instruments) are between 2 and 5 times more
reliable than vacuum or electric gyros. It doesn=99t matter if the
instruments are certified or experimental, apart from the first 50 or so
hours.
Flying in IMC in any single engined aircraft is inherently more risky
than in VMC, but the level of increased risk is not easy to determine.
The impact of electrical phenomenon on single engined aircraft in IMC
are very difficult to measure from accident/incident data as there are
very few reported incidents.
I work at a Part 145 repair company, we maintain and repair several
types of composite light aircraft. In general the outer layer of carbon
has aluminium woven into it to improve conductivity =93 carbon
laminates are conductive. There is usually 20mm wide 1mm thick aluminium
bonding straps throughout the aircraft. They all use static discharge
wicks on the te of the wing tips and empennage. We have a fleet of
around 20 aircraft on our books for maintenance, most involved in
commercial training, and have not had a similar incident to yours
reported. Including such =9Cprotection=9D in a homebuilt
would not be something to be undertaken lightly, I am not convinced it
would buy very much except a longer build time, lower useful load and
corroded wings.
In the UK certified gliders (with little bonding or protection)
regularly fly in IMC. I am not aware of any static problems. The
incident of the K-21 being blown apart by lightning was when the glider
knowingly flew (in VMC) close but not into a CB, it wasn=99t a
embedded in stratus. The strike was so severe that the moisture within
the structure was heated so rapidly that it vapourised and blew the
structure apart, the control rods were melted and fused together.
Fortunately the pilots wore parachutes and escaped. The amount of energy
absorbed by the aircraft meant that it was unlikely to have been
survivable no matter how much bonding was used.
Most recreational pilots don=99t fly in hard IMC for very long
=93 even in the UK where we seem to have more low stratus than
many other countries. The usual operational profile is to climb through
the clag to VMC on top. Clearly commercial flight training spends much
more time in the soup, but certainly here homebuilts cannot be used for
commercial training. The conclusion we came to was that no additional
requirements from the bonding perspective were required for homebuilt
aircraft to fly in IMC, except to impose a limitation not to fly near
areas of forecast or actual thunderstorms =93 although that is not
policeable but it keeps the certification authorities happy!
Peter
From: owner-aeroelectric-list-server@matronics.com
<mailto:owner-aeroelectric-list-server@matronics.com>
<owner-aeroelectric-list-server@matronics.com
<mailto:owner-aeroelectric-list-server@matronics.com> > On Behalf Of
Sebastien
Sent: 03 March 2022 23:24
<mailto:aeroelectric-list@matronics.com> >
Subject: Re: AeroElectric-List: Static Events On Composite Airplanes
Hello Bill,
I don't have any data, just anecdotal evidence that flying IMC with a
composite amateur built aircraft is risky. You could look up the bonding
section in the certification requirements for composite aircraft, that
would probably give you a good idea of how thorough you have to be to
make a composite aircraft safe for IMC flights.
I have flown several different models of certified fiberglass aircraft
IFR. These aircraft are designed and built with conductive mesh
throughout the airframe to dissipate any static electricity build up.
Despite this, on two different occasions I have had severe problems with
static while IMC requiring a diversion. In one case it was so bad that
the student was getting electric shocks through the yoke. The other
incident took out half the avionics and magnetized the compass.
As for lightning, I think usually the aircraft gets destroyed by
turbulence induced loss of control before getting close enough to be hit
by lightning but I know of one incident with a glider in the UK which
was flying near what they thought was stratus cloud but had an embedded
CB in it. The composite glider (factory built but with no bonding
material embedded) basically exploded when it was hit. Very high
resistance = very high temperature during a lightning strike and the
entire airframe disintegrated. They found themselves falling in free air
but both successfully deployed their parachutes and survived. The
passenger was on his first small aircraft flight.
I think anyone flying IMC regularly in a composite amateur built
aircraft is going to run into a problem sooner or later. I know of no
solution, everyone just seems to roll the dice and hope they keep
getting 7s.
On Thu, Mar 3, 2022 at 8:28 AM William Hunter
<billhuntersemail@gmail.com <mailto:billhuntersemail@gmail.com> > wrote:
Greetings,
I fly a composite airplane that is built using a foam core with regular
fiberglass BID material bonded to the core for most of the construction
and flight control surfaces and then in some small sections there is
some carbon fiber bonded in to certain places of the structure where
needed for extra support so essentially the airplane is mostly core foam
and regular fiberglass.
There has been one static event in the community where the pilot of this
type of airplane who had a full EFIS system was climbing through dry
snow and his Garmin EFIS screen blacked out and then a few minutes later
the screen returned however the autopilot was still operating as usual
so it seems that it was only the EFIS screen that was affected during
the event and not the rest of the system. The data was downloaded and
sent to Garmin and they determined that it was a static discharge. I
have not heard what their remedy was for this concern.
So the questions that popped up are the following...
-How does the builder/ pilot mitigate the risk of this type of issue
from happening in a composite airplane?
-Is this a common concern in airplanes designed like this?
-There are commercially available static wicks that could be attached to
the structure however if the structure does not have any kind of
conductive material/ mesh embedded in the fiberglass I would not think
that the static buildup would get to the static wicks.
-The plans do not call for any type if bonding cable be installed to
electrically connect the flight controls to the fuselage so the question
is...should there be bonding straps in this type of airplane?
-What risks does an airplane like this have when flying near lightning?
-If the fuselage was not conductive and there is no practical way to get
it to discharge the static through static wicks then what other
technique is there to mitigate the risk of static buildup damaging/
disabling the electrical components of the airplane?
-And other questions that we are not smart enough to know to ask?
THANKS all and as always I am very grateful for your advice and
expertise.
Bill
Message 2
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| Subject: | Re: Static Events On Composite Airplanes |
In Canada we have a similar process. Each aircraft is approved for IFR on a
case by case basis. A couple times I have had to go to great lengths to
educate the Airworthiness Inspector on their own regulations in order to
get an aircraft passed. There is no load analysis or power architecture
analysis though. Maybe a good thing considering the inspectors in question
but it's certainly an area rife for improvement.
One builder had spent a massive amount of time creating layers of backup
systems for his electrically dependent engine and his IFR avionics. After a
couple hundred hours on the aircraft he finally got his VFR restriction
removed and hired me to get his instrument rating. Early on in perfect VMC
at 6500' flying over an airport with 3 runways I asked him to turn the
master off to test his backups, he refused ... he'd never tested it in the
air or on the ground lol. We corrected both before taking the aircraft IMC.
A beautiful aircraft.
On Mon, Mar 7, 2022 at 3:07 PM Peter Pengilly <Peter@sportingaero.com>
wrote:
> Hello Sebastien,
>
> All I can offer is that we searched the accident databases to find out
> what had been reported. If instances such as yours don=99t get repo
rted then
> nothing will get done until there is a nasty accident. Any decent safety
> management system seeks to collect =9Cnear-miss=9D data as a
predictor of where
> accidents might happen, it is disappointing GA doesn=99t do that.
>
>
> Many homebuilders don=99t understand how their aircraft could fail
and put
> far too much trust in the promises of electronics salesmen. The UK CAA
> forced us to assess each individual aircraft applying for an IMC clearanc
e
> to look at the power architecture of the instrument system. Several have
> had to make changes to increase the robustness/resilience or to look at
> what loads must be shed if the alternator fails. We have no requirements
> for static build-up protection.
>
>
> Peter
>
>
> *From:* owner-aeroelectric-list-server@matronics.com <
> owner-aeroelectric-list-server@matronics.com> *On Behalf Of *Sebastien
> *Sent:* 06 March 2022 01:31
> *To:* aeroelectric-l. <aeroelectric-list@matronics.com>
> *Subject:* Re: AeroElectric-List: Static Events On Composite Airplanes
>
>
> Hello Peter,
>
>
> Like I said, I have no data. I included the anecdotes specifically becaus
e
> I'm not sure that "We found no similar instances to yours when we searche
d
> the accident/incident reports" is data either. An incident which takes ou
t
> half of the aircraft avionics and requires a diversion to a nearby VMC
> airport would not show up in any accident database that I am aware of. No
> one was injured and the aircraft did not suffer any damage after the
> initial event. Both my incidents were in uncontrolled airspace so
> definitely no report there. A friend of mine lost all avionics except for
a
> radio and the turn co-ordinator in an IMC static event over the rocky
> mountains and required a great deal of help from controllers to safely ge
t
> the aircraft on the ground. Again, no database that I know of contains th
is
> incident and it only happened 15 years ago.
>
>
> Instrument failures happen for many reasons and when training IFR I go to
> great lengths to make sure my students are as prepared as possible for th
em
> but we rarely simulate losing most of the instrument panel. The closest w
e
> get to that scenario is an alternator failure that eventually leaves us o
n
> backup battery power for the approach.
>
>
> These days I regularly see newly built amateur built that are IFR capable
.
> Many of these are built by pilots who have no IMC experience. Sometimes t
he
> builder has given some thought to fault tolerance, other times not. I hav
e
> yet to see one where the builder gave any thought to static problems, so
I
> share my anecdotes and my caution to encourage builders to think about th
e
> possibilities. All flying is risky to some degree so I suppose my stateme
nt
> isn't very useful. I'm just trying to point out the increase in risk.
>
>
> On Sat, Mar 5, 2022 at 1:01 AM Peter Pengilly <Peter@sportingaero.com>
> wrote:
>
> Dear Bill & Sebastien,
>
>
> - flying IMC with a composite amateur built aircraft is risky
>
>
> I really disagree with this statement. I also really disagree that the
> certification rules are particularly relevant as they are designed to
> mainly address lightning strike. It is worth looking at the data that is
> available.
>
>
> Some years ago I undertook an investigation for the UK homebuilt
> association into IMC & night flying for homebuilts as UK homebuilts were
> limited to day VFR. The conclusion was the risk of lightning strike on
> single engined aircraft in IMC is so small it is not worth worrying about
.
> The risk of lightning strike in VMC was already accepted (and is also ver
y
> small). From the accident data for 40 years of flying in the UK and 10
> years in the US there was only one instance of a single engined aircraft
> flying in IMC being hit by lightning, a 210 in the eastern US, and that
> ended with a diversion and safe landing. For whatever reason single engin
ed
> aircraft are not hit by lightning. I do completely agree that the
> thunderstorm is much more likely to kill you than being hit by lightning!
> In the period we looked at around 60 aircraft, flying in IMC, came to gri
ef
> because of flying into a thunderstorm.
>
>
> I have no experience of the effects of static discharge. We found no
> similar instances to yours when we searched the accident/incident reports
,
> but that was 10 years ago and the number of EFIS equipped aircraft has
> increased considerably in the intervening years. However, EFIS (or solid
> state instruments) are between 2 and 5 times more reliable than vacuum or
> electric gyros. It doesn=99t matter if the instruments are certifie
d or
> experimental, apart from the first 50 or so hours.
>
>
> Flying in IMC in any single engined aircraft is inherently more risky tha
n
> in VMC, but the level of increased risk is not easy to determine. The
> impact of electrical phenomenon on single engined aircraft in IMC are ver
y
> difficult to measure from accident/incident data as there are very few
> reported incidents.
>
>
> I work at a Part 145 repair company, we maintain and repair several types
> of composite light aircraft. In general the outer layer of carbon has
> aluminium woven into it to improve conductivity =93 carbon laminate
s are
> conductive. There is usually 20mm wide 1mm thick aluminium bonding straps
> throughout the aircraft. They all use static discharge wicks on the te of
> the wing tips and empennage. We have a fleet of around 20 aircraft on our
> books for maintenance, most involved in commercial training, and have not
> had a similar incident to yours reported. Including such =9Cprotect
ion=9D in a
> homebuilt would not be something to be undertaken lightly, I am not
> convinced it would buy very much except a longer build time, lower useful
> load and corroded wings.
>
>
> In the UK certified gliders (with little bonding or protection) regularly
> fly in IMC. I am not aware of any static problems. The incident of the K-
21
> being blown apart by lightning was when the glider knowingly flew (in VMC
)
> close but not into a CB, it wasn=99t a embedded in stratus. The str
ike was so
> severe that the moisture within the structure was heated so rapidly that
it
> vapourised and blew the structure apart, the control rods were melted and
> fused together. Fortunately the pilots wore parachutes and escaped. The
> amount of energy absorbed by the aircraft meant that it was unlikely to
> have been survivable no matter how much bonding was used.
>
>
> Most recreational pilots don=99t fly in hard IMC for very long
=93 even in the
> UK where we seem to have more low stratus than many other countries. The
> usual operational profile is to climb through the clag to VMC on top.
> Clearly commercial flight training spends much more time in the soup, but
> certainly here homebuilts cannot be used for commercial training. The
> conclusion we came to was that no additional requirements from the bondin
g
> perspective were required for homebuilt aircraft to fly in IMC, except to
> impose a limitation not to fly near areas of forecast or actual
> thunderstorms =93 although that is not policeable but it keeps the
> certification authorities happy!
>
>
> Peter
>
>
> *From:* owner-aeroelectric-list-server@matronics.com <
> owner-aeroelectric-list-server@matronics.com> *On Behalf Of *Sebastien
> *Sent:* 03 March 2022 23:24
> *To:* aeroelectric-l. <aeroelectric-list@matronics.com>
> *Subject:* Re: AeroElectric-List: Static Events On Composite Airplanes
>
>
> Hello Bill,
>
>
> I don't have any data, just anecdotal evidence that flying IMC with a
> composite amateur built aircraft is risky. You could look up the bonding
> section in the certification requirements for composite aircraft, that
> would probably give you a good idea of how thorough you have to be to mak
e
> a composite aircraft safe for IMC flights.
>
>
> I have flown several different models of certified fiberglass aircraft
> IFR. These aircraft are designed and built with conductive mesh throughou
t
> the airframe to dissipate any static electricity build up. Despite this,
on
> two different occasions I have had severe problems with static while IMC
> requiring a diversion. In one case it was so bad that the student was
> getting electric shocks through the yoke. The other incident took out hal
f
> the avionics and magnetized the compass.
>
>
> As for lightning, I think usually the aircraft gets destroyed by
> turbulence induced loss of control before getting close enough to be hit
by
> lightning but I know of one incident with a glider in the UK which was
> flying near what they thought was stratus cloud but had an embedded CB in
> it. The composite glider (factory built but with no bonding material
> embedded) basically exploded when it was hit. Very high resistance = ve
ry
> high temperature during a lightning strike and the entire airframe
> disintegrated. They found themselves falling in free air but both
> successfully deployed their parachutes and survived. The passenger was on
> his first small aircraft flight.
>
>
> I think anyone flying IMC regularly in a composite amateur built aircraft
> is going to run into a problem sooner or later. I know of no solution,
> everyone just seems to roll the dice and hope they keep getting 7s.
>
>
> On Thu, Mar 3, 2022 at 8:28 AM William Hunter <billhuntersemail@gmail.com
>
> wrote:
>
> Greetings,
>
> I fly a composite airplane that is built using a foam core with regular
> fiberglass BID material bonded to the core for most of the construction a
nd
> flight control surfaces and then in some small sections there is some
> carbon fiber bonded in to certain places of the structure where needed fo
r
> extra support so essentially the airplane is mostly core foam and regular
> fiberglass.
>
> There has been one static event in the community where the pilot of this
> type of airplane who had a full EFIS system was climbing through dry snow
> and his Garmin EFIS screen blacked out and then a few minutes later the
> screen returned however the autopilot was still operating as usual so it
> seems that it was only the EFIS screen that was affected during the event
> and not the rest of the system. The data was downloaded and sent to Garm
in
> and they determined that it was a static discharge. I have not heard wha
t
> their remedy was for this concern.
>
> So the questions that popped up are the following...
>
> -How does the builder/ pilot mitigate the risk of this type of issue from
> happening in a composite airplane?
>
> -Is this a common concern in airplanes designed like this?
>
> -There are commercially available static wicks that could be attached to
> the structure however if the structure does not have any kind of conducti
ve
> material/ mesh embedded in the fiberglass I would not think that the stat
ic
> buildup would get to the static wicks.
>
> -The plans do not call for any type if bonding cable be installed to
> electrically connect the flight controls to the fuselage so the question
> is...should there be bonding straps in this type of airplane?
>
> -What risks does an airplane like this have when flying near lightning?
>
> -If the fuselage was not conductive and there is no practical way to get
> it to discharge the static through static wicks then what other technique
> is there to mitigate the risk of static buildup damaging/ disabling the
> electrical components of the airplane?
>
> -And other questions that we are not smart enough to know to ask?
>
> THANKS all and as always I am very grateful for your advice and expertise
.
>
> Bill
>
>
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