Instrument failures
PPRuNe Handmaiden
Joined: Feb 1997
Posts: 4,914
Likes: 184
From: Duit On Mon Dei
Yeah, had a couple of instrument failures along the way.
The usual vac pump failures in singles etc. No biggy, VMC.
Also used to happen in the Islander too. Was only permitted to continue flight (multi sector) if VMC was assured. I had to pull the little plastic drive out of it and then secure.
Only happened with dry vac pumps, never seen a wet vac pump fail.
Slave mechanism failures. Good idea to check it on the runway.
AHARS failure in the Dash 8. Absolutely nothing like the sim detail.
(basicly all the control instruments. Atitude, heading reference system). No way was I going in IMC with that one.
ASI over readings. Had to keep cross checking the captain's. Pain.
The usual vac pump failures in singles etc. No biggy, VMC.
Also used to happen in the Islander too. Was only permitted to continue flight (multi sector) if VMC was assured. I had to pull the little plastic drive out of it and then secure.
Only happened with dry vac pumps, never seen a wet vac pump fail.
Slave mechanism failures. Good idea to check it on the runway.
AHARS failure in the Dash 8. Absolutely nothing like the sim detail.
(basicly all the control instruments. Atitude, heading reference system). No way was I going in IMC with that one.
ASI over readings. Had to keep cross checking the captain's. Pain.
Simplicate and Add Lightness
Joined: Apr 2002
Posts: 254
Likes: 0
From: EGSG, mainly
Pitot Flooding
I had a wierd one (to me anyway) a few weeks ago when, after being parked at a slightly 'unusual attitude' overnight in pouring rain, and after 1 normal short flight, the ASI and altimeters both failed at about 300' after take-off.
After the initial disbelief this resulted in a curt call back to the field - then blanking everything around me out and concentrating on doing a circuit pretty much by eye and tacho.
It was uneventful, although being fairly new to type and at an unfamiliar airifield didn't help.
One of the FI's at the club just sucked (gently!) on the static vent, spat out a lot of water, and assured me all would be OK - which it was.
Afterwards I just felt annoyed that this type of flying hadn't been covered in training...
After the initial disbelief this resulted in a curt call back to the field - then blanking everything around me out and concentrating on doing a circuit pretty much by eye and tacho.
It was uneventful, although being fairly new to type and at an unfamiliar airifield didn't help.
One of the FI's at the club just sucked (gently!) on the static vent, spat out a lot of water, and assured me all would be OK - which it was.
Afterwards I just felt annoyed that this type of flying hadn't been covered in training...
Joined: Dec 1998
Posts: 4,282
Likes: 6
From: Escapee from Ultima Thule
I've had a vac. pump fail, losing my AI & DI, 2 x AI only, and 2xASI. The vac pump & 1 x AI were both at night in a part of Oz with stuff all ground lighting. The ASI and 1 x AI were daytime in IMC. It was a bug for one ASI, an automatic/airspeed deactivated pitot cover the other ASI failure and a stuffed bearing (I think) for the AI. The AI wouldn't sit straight ie it was at odds with the flight director command bars, the second AI & the performance instruments.
The vac failure & one of the sole AI failures were at night in a typically minimally equipped C172 ie single of each instrument. The single AI was during a student's Night VFR navex, the vac pump while I was doing the same student's Night VFR flight test. Unlucky ******! He passed, in part due to handling the failure so well.
If it can fail, it will. If you fly using mechanical instruments then sooner or later one will fail. It's no joke about needing decent lim.panel skills including lim. panel unusual attitude recovery. As was rightly said: Have with you something to cover the failed instrument(s), most importantly covering a failed AI.
Whatever you do, don't ever fly something in IMC that doesn't have two independent attitude references. Either two direct sources ie AIs with independant power sources, or a direct + an indirect ie AI + TC/ASI, also independent power sources.
The vac failure & one of the sole AI failures were at night in a typically minimally equipped C172 ie single of each instrument. The single AI was during a student's Night VFR navex, the vac pump while I was doing the same student's Night VFR flight test. Unlucky ******! He passed, in part due to handling the failure so well.
If it can fail, it will. If you fly using mechanical instruments then sooner or later one will fail. It's no joke about needing decent lim.panel skills including lim. panel unusual attitude recovery. As was rightly said: Have with you something to cover the failed instrument(s), most importantly covering a failed AI.
Whatever you do, don't ever fly something in IMC that doesn't have two independent attitude references. Either two direct sources ie AIs with independant power sources, or a direct + an indirect ie AI + TC/ASI, also independent power sources.
Some more money for Capt PPRuNe
Joined: Jan 2002
Posts: 271
Likes: 1
From: Ici
Had an "interesting" experience last weekend (Monday 25th).
Departed Menorca (R01) with a clearance "not above 1000ft" consistant with the local controlled airspace (IFR). Menorca APP cleared me "stay below 1000ft, via point Echo (an easily identifiable point near to the Isles). A few minutes after takeoff the APP controller (obviously very concerned) ordered me to descend as he believed I was in the IFR class A airspace surrounding the region. His readout was reporting 2500ft
I assured him several times that I was definately at no more than 800ft agl, he eventually seemed to accept this although did continue to order me to descend. I could not have descended much further without unhappy consequences.
It turned out that my altitude encoder/transponder had failed. This was further verified by Perpignan APP - however their readout for me had reversed in error - I was at FL45 and their readout (secondary radar) was FL30. I flew the rest of the journey without mode C selected.
Departed Menorca (R01) with a clearance "not above 1000ft" consistant with the local controlled airspace (IFR). Menorca APP cleared me "stay below 1000ft, via point Echo (an easily identifiable point near to the Isles). A few minutes after takeoff the APP controller (obviously very concerned) ordered me to descend as he believed I was in the IFR class A airspace surrounding the region. His readout was reporting 2500ft
I assured him several times that I was definately at no more than 800ft agl, he eventually seemed to accept this although did continue to order me to descend. I could not have descended much further without unhappy consequences.
It turned out that my altitude encoder/transponder had failed. This was further verified by Perpignan APP - however their readout for me had reversed in error - I was at FL45 and their readout (secondary radar) was FL30. I flew the rest of the journey without mode C selected.
Some more money for Capt PPRuNe
Joined: Jan 2002
Posts: 271
Likes: 1
From: Ici
WCollins, what did surprise me though was the controller's reluctance to accept that I was really only at 800ft as per the clearance. Over here (UK) they would always verify a mode C readout via the RT (ie check with the pilot).
I guess the MAH controller was just playing safe especially given the possibility of missunderstanding each others' accents. Still it was frustrating given that I had understood and readback (several times) the clearance, confirmed my actual alt on the qnh (which was 1012 so pretty close to FL pressure reference) yet was being ordered to descend. As I left the zone he was still reporting my recorded alt as 2500' (to IFR traffic) but stating that the pilot was saying he was at 800' only.
I am also surprised that the error (fault) had reversed in direction at Perpignan. Obviously there was a genuine problem with the Mode C.
Was all a bit of a shame really. I had a 800nm journey ahead and didn't need this at the very beginning. Wifey was getting "concerned" (she was listening to the RT) - I assured her that equipment failures were not a big issue in their own right - its how you handle them.
Rich
I guess the MAH controller was just playing safe especially given the possibility of missunderstanding each others' accents. Still it was frustrating given that I had understood and readback (several times) the clearance, confirmed my actual alt on the qnh (which was 1012 so pretty close to FL pressure reference) yet was being ordered to descend. As I left the zone he was still reporting my recorded alt as 2500' (to IFR traffic) but stating that the pilot was saying he was at 800' only.
I am also surprised that the error (fault) had reversed in direction at Perpignan. Obviously there was a genuine problem with the Mode C.
Was all a bit of a shame really. I had a 800nm journey ahead and didn't need this at the very beginning. Wifey was getting "concerned" (she was listening to the RT) - I assured her that equipment failures were not a big issue in their own right - its how you handle them.
Rich
