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-   -   Comms & Navaid Failure in IMC (https://www.pprune.org/pacific-general-aviation-questions/420754-comms-navaid-failure-imc.html)

Hot High Heavy 12th Jul 2010 06:06

Comms & Navaid Failure in IMC
 
I am just working my way through the IREX study material prior to doing the MECIR and am 'loving' every minute of it! :ugh:

Anyway it has got me thinking about how hairy it must be to have a total comms/navaid failure whilst IFR and in IMC. Obviously there are procedures in the ERSA to follow in the event of this happening and a portable GPS might a handy lifesaver, combined with a WAC etc but has anyone been in this situation? How did you make a successful approach?

Further are there any 'old-timers':} out there that dealt with this, pre GPS days? I am thinking there must be some real good stories out there on this subject!

Jabawocky 12th Jul 2010 07:12

Garmin 296/396/495 is your answer.

Have two of everything. The IFR trainer I did my CIR in only had one A/H, which while legal is not so nice when you are doing night Navs in IMC for real :uhoh: and S/E (yes Wally I hear ya) and you have no idea of the Vac pumps histiry!

Could we have survived a vac pump failure..sure...in fact I seemed to fly VOR's better without a DG and A/H :eek: but had it been my aircraft two of everything please!

Jabair has a MEL that requires two functioning everything for IFR ops (yeah I know Wally its only one donk) and just like ForkAir Multiple GPS whether TSO'd or hand held or PC based are encouraged!:ok:

I bet you get some stories from the folks that will make us all want to walk in future! :\

FokkerInYour12 12th Jul 2010 07:27

headset with bluetooth for mobile phone also worthwhile too (with an ERSA with tower numbers)

Old Akro 12th Jul 2010 08:07

I think its easy to scare yourself with what might happen. A total comms / navaid failure requires an alternator failure, then fully discharging the battery. Not all that likely. If you have an alternator failure you're going toward VFR as fast as you can with as much as you can turned off. You'll be really surprised at how long the aeroplane will run on the battery. Unless you have pitot heat and a bunch of lights on, you should get a number of hours running on minimum electrics.

The 5 top most likely failures are:
1. Vacuum pump
2. Vacuum pump
3. Vacuum pump
4. Vacuum pump
5. Vacuum pump

After that its likely to be an individual component rather than a system, eg the AI.

My view is that a vac pump / AI / alternator failure etc is most likely to occur while you are flying on autopilot. So, its important to know where it is getting its information and how various failures will affect it. A vac pump failure on autopilot while you are flying along happily doing the quiz in the latest FSA magazine is an insidious thing.

I doubt that there is anything in ERSA that will help you. Especially since its essentially a VFR document, not an IFR document (and if you are serious about IFR, you'll most likely end up on Jepps). What you'll need is a deep & thorough understanding of the aeroplane's systems, good situational awareness and a good brain.

Is you autopilot rate based or position based? Analogue or digital? Does it take information from the AI or turn co-ordinator? How old is the vac pump? What vac pump system is there? when did you last test it? How old is the battery? Can you switch the alternator & battery separately? What do you do if there is a voltage regulator failure? Where is the voltage regulator? If its a twin does it have two voltage regulators or one for both engines (C310)? If you have 2 AI's are they both vacuum? Where are the static drains / alt static ports? Does the ammeter normally read zero in flight or show a charge? Do you have an instrument that shows battery voltage (eg JPI or some GPS units b& some digital clocks).

Forget ERSA, read the flight manual.

bushy 12th Jul 2010 09:29

It's Easy.
 
You just wind the altimeter back until it reads zero, then get out and go home!

Kiwi172 12th Jul 2010 09:42

Zapped
 
Yes these things do happen. I was flying in IMC at night in some pretty average weather when due to atmospheric conditions I lost both VORs, DME and all comms.:mad: The transponder was still flashing away happily. - No GPS onboard. Unbeknown to me the compass system had also taken a whack. It took a good 10 minutes for the things to discharge and for the avionics to slowly come back online. A pretty lonely existance while you contemplate what to do next. Keep your cell phone fully charged at all times! It may come in handy.

Wally Mk2 12th Jul 2010 11:12

God 'bushy' that cracked me up!!!:D

'jaba' ya know I only have yr welfare at heart here buddy:ok: Flying SE IFR is suicide BUT it's a suicidal personal choice I guess:)

A portable GPS as has been mentioned here is the way yo go if IFR is yr scene.
Also a constant knowledge of situational awareness whilst in IMC. I'd bet a LOT of IFR drivers just sit back watch the auto's fly the plane in solid IMC esspecially now with hyper accurate GPS gear with only a basic understanding of knowing exactly where they are in relation to terrain, I know I am guilty too at times of that.
Hand held transceivers are not that expensive either, another tool to have if yr an avid cloud lover:-)
Either way know yr plane & know the places ( printed material) where to find help

Quick story:

Aircraft, C210 (owned by Bishop Jobst)
Scene, Broome,daylight with a NVMC return to Broom.with but stormy wx about.
Task, pvt flight with some hapless caravaners I met during a trip around Oz.
Route,Nth from Broome along coast down along Prince Regent River then over to Kunners back via Derby into Broome with a planned night ldg.

Enroute to Kunners now late arvo I noticed the the radio's getting dull (digital readout). Anyway all else looked ok (battery/amps etc).
lowered the U/C & Flaps for arrival into Kunners & thought gee that was slowish. Green pilot here way back then:-)
Fueled up started the Conty (just fired on first compression) & set course for Broome NVMC after a very slow gear retraction. (yeah I know Jaba I was dumb back then flying SE at night!:E)

About half way home to Broome I had the inky darkness of the night sky INSIDE the plane! Total elect failure!!!......SH1T !!!!! Luckily it was a full moon & one could see the ground fairly clearly but was damn hard work flying the plane by hand using compass & WAC charts. Finally found Broome town lights buzzed over the town a few times changing pwr settings to hopefully get someone to come out & turn on the rwy lights. Fortunately they where on anyway so did manual gear ext as well as flapless ldg. Broome back then was much quieter.
My pax where great people, hardly screamed at all!!!:)
I got back to my caravan, changed my 'super-man' suit (undies) & quietly had a drink or three !!! Thank God it wasn't true IMC but was the hardest think I had ever done,well up to then at least!



Wmk2

Capt Fathom 12th Jul 2010 11:55

Murphy's Law.....

Had an alternator fail at night in a C172. 90 min flight down the QLD coast.
Nice clear moonlit night. No where to land. (No PAL then!)
Continued on with 30min skeds, with the master switch off in between to save the battery for arrival. No drama really.

Another at night, in western QLD, the compass in the Baron went tits up.
Came home using the moon as a reference until within navaid range!
(Compass bearing of moon provided by Flight Service... aahh the good old days!)

ForkTailedDrKiller 12th Jul 2010 12:42


Further are there any 'old-timers'http://images.ibsrv.net/ibsrv/res/sr...s/badteeth.gif out there that dealt with this, pre GPS days?
..... but we do live in the GPS age. I would not fly IFR without a portable GPS as backup.

Portable GPS and a mobile phone will get you safely out of most situations. I have had 2 x alternator failures (not in the FTDK) resulting in total electrical failure - portable GPS and mobile phone got me down and home.

FTDK has: Pressure AH and electric AH, 2 x VHF, VOR, ILS, ADF, G430W, G495 portable, handheld VHF with VOR indicator, Sat phone, 3 x other non-TSO GPS, 4 x torches.

Dr :8

PS: You will minimize your chances of having things fail if you don't let Jaba near your aeroplane!

A37575 12th Jul 2010 14:35


I think its easy to scare yourself with what might happen. A total comms / navaid failure requires an alternator failure, then fully discharging the battery. Not all that likely.
But it has happened and Sod's law ensures it will be in IMC. It took one hidden circuit breaker (no decal, either to indicate the position of the circuit breaker) to be inadvertently jagged. Loss of all electrics and the battery of course. Night in cloud en route West Sale to Essendon. Loss of all comms and navaids and of course Sod's law prevailed again when the gear was inoperative due no electrics. No flaps or landing lights and no cockpit lights. Again Sod's law hit hard when the emergency landing gear handle was found to be jammed and inoperative.

frigatebird 12th Jul 2010 22:19

Also had an electrical failure in the Cessna before its engine (and components) overhaul, due to a broken wire on the last hour of night on a flight home. Night VMC, so weather was not a problem, and just a little moon. Also carry 3 torches on night flights. Coming into the circuit just after the Flying Doctor had departed, the radio and panel lights having given up, the runway lights were still on but the windsock lights were flashing. A quick join, but lined up on final the lights went out. There was just enough light to make out the runway and judge the landing. Have carried a hand held portable VHF as part of the night equipment in the aircraft since, but still need to get a connection from the mobile phone to the headset to cut out the background noise if its needed.

ForkTailedDrKiller 13th Jul 2010 07:08


but still need to get a connection from the mobile phone to the headset to cut out the background noise if its needed
Helps - but not essential. Just stick the phone under the headset ear cup!

Dr :8

Bevan666 13th Jul 2010 23:45


FTDK has: Pressure AH and electric AH, 2 x VHF, VOR, ILS, ADF, G430W, G495 portable, handheld VHF with VOR indicator, Sat phone, 3 x other non-TSO GPS, 4 x torches.
... and one engine :}

Capt Fathom 14th Jul 2010 00:40


FTDK has: Pressure AH and electric AH, 2 x VHF, VOR, ILS, ADF, G430W, G495 portable, handheld VHF with VOR indicator, Sat phone, 3 x other non-TSO GPS, 4 x torches.
... and a partridge in a pear tree!

ForkTailedDrKiller 14th Jul 2010 00:49


... and a partridge in a pear tree!
Bugger! Where can I get one of those? Could be useful emergency rations! :E

Dr :8

Baldnfat 14th Jul 2010 01:40

Dumb luck
 
Had a non genuine voltage regulator (owner/operator modification) fail on a return trip from Arkaroola to the not quite so remote home base in Day VMC conditions. (No GPS back n those days.)
It fried everything, Nav/Comms, the T+B anything that was connected to the bus board. It was only at around 50 feet on the upwind leg on climb (sort of) during a hot (38 C) afternoon. I was slow to switch the master off as the flaps still needed to be raised (and that first 2-3 seconds of panic in an emergengy is real):eek:. The fully loaded 206 did have a serviceable Vac pump and the AH was working.
That would have been the only thing that would have saved my ar#e if it had happened the day before when I departed an hour before first light (solo) on a charter / pick up. I only had the the hurricane lamps to light the strip and it would have been an interesting morning as there was only the smallest bit of moonlight and no other hint of a horizon outside.

The stupid things we do when we have a fresh CPL and think we are invincible. :(

NOtimTAMs 14th Jul 2010 07:11

Wally said: "Also a constant knowledge of situational awareness whilst in IMC. I'd bet a LOT of IFR drivers just sit back watch the auto's fly the plane in solid IMC esspecially now with hyper accurate GPS gear with only a basic understanding of knowing exactly where they are in relation to terrain"

I fly SEIFR a bit and my fellow pilots think I'm a bit OCD when I've got the autopilot tracking the GPS signal (from the terrain-enabled TSO146a GPS) on top of 8/8 or at night and I'm also marking times off on 10 nm markers on the appropriate VTC/VNC/WAC, with a backup GPSIII Pilot on the yoke. My reasoning is that when/if the donk fails (or the vacuum or the electrics) I will know EXACTLY where I am in relation to terrain (and alternates) without the GPS and can start DR etc with the minimum of sweat and panic to add to dealing with the sitation...... and it gives me something to do while listening to the MP3's....

(And yeah, I've got the backup hand held VHF/VOR patched into an extra antenna and mobile phone into the intercom and more LED torches than I like to admit.....). The only hard bit then is flying an AH failure if it occurs....

Capt Fathom 14th Jul 2010 08:02

There was a guy some years ago, in the early days of GPS, tracking Brisbane direct Cairns.

Penetrating CTA as he went along his merry way.

When quizzed by ATC as to his present position, the answer was along the lines of....

"I'm 350 nm from Cairns!"

He had no idea where he was!

Jabawocky 14th Jul 2010 08:55

Notimtams...........all you need now is a Tablet and WAC charts.....that will help you get your 10nm marks and times spot on:ok:

And you can pprune in flight :eek:

PA39 14th Jul 2010 11:47

In the late 80's had complete electrical shut down out of Sydney at 1.00am (Dual alternator failure!! ) everything disappeared just after departures asked "ops normal" because my climb gradient and speed on radar was too low. I replied affirmative even though i had the gear still out and could not retract. Options were to head for PMQ or go back for the full monty (fire engines rescue etc) at YSSY. So off i went all the way to PMQ with a torch and a load of fresh sea food as freight. The night was CAVOK thanks to the Gods, and a very slow trip, landed PMQ (Right hand man who was there to help me with the freight actvated the PAL for me) and I phoned FS to cancel SAR....a little hostility but good guys who understood. :\


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