Do you have to snag intermittent problems?

This forum has been developed to discuss aviation related topics.

Moderators: ahramin, sky's the limit, sepia, Sulako, lilfssister, North Shore, I WAS Birddog

Post Reply
digits_
Rank 10
Rank 10
Posts: 2182
Joined: Mon Feb 14, 2011 2:26 am

Do you have to snag intermittent problems?

Post by digits_ » Tue May 07, 2019 7:36 am

Hi all,

some discussions with other pilots raised the following question: do you have to snag intermittent/one time problems?

I don't want to focus on one specific case, but some examples:
- radio stops working, you switch it off and on again and it works
- low fuel light comes on during cruise for 5 seconds, then goes out again. there was plenty of fuel in tanks, even after landing you still have over half tanks left
- ATC loses your mode C, you recycle the transponder and everytying works fine again
- you feel a weird vibration while flying, it lasts 10 minutes and then it stops
- ....

So basically, something happens once that is not common to the plane you are flying. It's a bit lik a snag that fixes itself.

Do you legally have to snag these things?

I'm not talking about what's safe or wise to do, I'd like to focus strictly on the legalities for this topic.

Regards,
digits
---------- ADS -----------
  

corethatthermal
Rank 3
Rank 3
Posts: 184
Joined: Tue Feb 12, 2019 7:27 pm

Re: Do you have to snag intermittent problems?

Post by corethatthermal » Tue May 07, 2019 8:08 am

Yes! Reasons to follow if there are not 10 replies by the end of the day!
---------- ADS -----------
  

altiplano
Rank 11
Rank 11
Posts: 3503
Joined: Sat Jan 22, 2005 2:24 pm

Re: Do you have to snag intermittent problems?

Post by altiplano » Tue May 07, 2019 9:11 am

You could snag it just for tracking recurrent snags...
"such and such stopped working, system reset, functions okay"

I don't know if I would do that with every system on every type, a light flashing for a split second, a brief one off noise, ATC momentary loss of mode C ... that's just flying airplanes sometimes... can depend your amount of experience on that specific fin and seeing the issue recurring... or seeing a history in the defect log...

But if in doubt, snag it...
---------- ADS -----------
  

Capt. Underpants
Rank 3
Rank 3
Posts: 100
Joined: Tue Oct 05, 2010 5:04 am

Re: Do you have to snag intermittent problems?

Post by Capt. Underpants » Tue May 07, 2019 9:42 am

Most of the MEL preambles I've seen state that if a system doesn't perform as per its intended function - even intermittently - then it needs to be recorded in the log book. Even if maintenance subsequently signs it off as "ground checked serviceable", you have started a paper trail that will alert subsequent crews to a problem they could face.
---------- ADS -----------
  

Heliian
Rank (9)
Rank (9)
Posts: 1487
Joined: Wed Apr 29, 2009 2:14 pm

Re: Do you have to snag intermittent problems?

Post by Heliian » Tue May 07, 2019 10:27 am

Yes, see recurring defects.
---------- ADS -----------
  

digits_
Rank 10
Rank 10
Posts: 2182
Joined: Mon Feb 14, 2011 2:26 am

Re: Do you have to snag intermittent problems?

Post by digits_ » Tue May 07, 2019 11:37 am

I like the replies.

Now, what rule would you be breaking if you did not snag the plane? After all, you can prove that the plane works before you go flying. You can even prove that everything in the plane works after you land.
---------- ADS -----------
  

photofly
Top Poster
Top Poster
Posts: 7128
Joined: Tue Jan 18, 2011 4:47 pm
Location: Making aviation exhausting, everywhere

Re: Do you have to snag intermittent problems?

Post by photofly » Tue May 07, 2019 3:02 pm

Breaking a rule and it being possible to prove you broke a rule are two different things.

The rule you'd be breaking is 605.94(1). The fine is up to $3000 per occurence for individuals, $15,000 for companies. That's three times the standard fine. See paragraph 9 of schedule 1 for what you have to log.

There are a whole bunch of TATC appeals from enforcement decisions on that.
---------- ADS -----------
  
Kirk: This is a dangerous mission. Likely, one of us will die. The landing party will be me, Spock, McCoy, and Ensign Ricky.
Ensign Ricky: Aw, crap.

rigpiggy
Rank 10
Rank 10
Posts: 2320
Joined: Sun Jan 16, 2005 7:17 pm
Location: west to east and west again

Re: Do you have to snag intermittent problems?

Post by rigpiggy » Tue May 07, 2019 4:31 pm

A place I worked at prior, I was given sh!t by the mechs for "writing it in the book" I responded why I bother, you just call it GTS. We can only fix it if they buy us parts. I said no problem, I will keep snagging it. Well we will keep putting GTS in the book. Well the next mx audit, it will come up as a "finding" amazingly they fixed it thereafter
---------- ADS -----------
  

digits_
Rank 10
Rank 10
Posts: 2182
Joined: Mon Feb 14, 2011 2:26 am

Re: Do you have to snag intermittent problems?

Post by digits_ » Tue May 07, 2019 5:11 pm

photofly wrote:
Tue May 07, 2019 3:02 pm
The rule you'd be breaking is 605.94(1). The fine is up to $3000 per occurence for individuals, $15,000 for companies. That's three times the standard fine. See paragraph 9 of schedule 1 for what you have to log.

There are a whole bunch of TATC appeals from enforcement decisions on that.
Thank you.

Paragraph 9 says:
Particulars of any defect in any part of the aircraft or its equipment that becomes apparent during flight operations
Is a one time intermittent abnormality a defect?

Not trying to be pedantic, I'm honestly curious what qualifies as a defect.
---------- ADS -----------
  

photofly
Top Poster
Top Poster
Posts: 7128
Joined: Tue Jan 18, 2011 4:47 pm
Location: Making aviation exhausting, everywhere

Re: Do you have to snag intermittent problems?

Post by photofly » Tue May 07, 2019 6:03 pm

Defect:

defect noun
de·​fect | \ ˈdē-ˌfekt , di-ˈfekt \
Definition of defect (Entry 1 of 2)
1a : an imperfection that impairs worth or utility : SHORTCOMING
the grave defects in our foreign policy
A defect prevented the DVD from playing properly.
b chemistry : an imperfection (such as a vacancy or an unlike atom) in a crystal lattice (see LATTICE sense 2)
2 : a lack of something necessary for completeness, adequacy, or perfection : DEFICIENCY
a hearing defect
Is a one time intermittent abnormality a defect?
You're not entitled to decide it's "one time", and not enter it in the log. Because if you so decide, the next person to whom it happens is also going to decide it's one time and not enter it into the log...

I would feel a whole lot happier about this if "the Minister" was consistently of the opinion that a defect entered into the journey log did not ground the aircraft, which is what the Minister argued in on TATC case (that I can't find right now.)

But this other TATC case seems to address your question:
http://www.tatc.gc.ca/decision/decision ... 7&lang=eng
[43] The Appeal Panel is of the view that the Review Member erred in his appreciation of what constituted a reportable defect. The illuminated generator light was a reportable defect. In fact, section 3.2.1 of Air Mikisew's MCM provides a rather low threshold for what constitutes a defect. The MCM is a Transport Canada approved document and compliance with it is mandatory. The MCM states that even minor issues with the cabin upholstery are considered a defect which is reportable in the journey log by the flight crew. Additionally, section 3.2.3 of the MCM also requires that any defects which occur more than three times over the course of fifteen flight cycles must be investigated and terminating action must be taken to ensure that the defect does not reoccur. If the generator light issue is not recorded, there is no way for the Director of Maintenance, who is responsible for detecting and correcting recurring defects, to become aware of the problem. Therefore, for these reasons, and the over-arching policy concerns of safety, there is no question in the Appeal Panel's mind that the generator light indicator was a defect......
Seriously, if anyone has trouble sleeping, the TATC website appears to be the answer.
---------- ADS -----------
  
Kirk: This is a dangerous mission. Likely, one of us will die. The landing party will be me, Spock, McCoy, and Ensign Ricky.
Ensign Ricky: Aw, crap.

helicopterray
Rank 4
Rank 4
Posts: 212
Joined: Thu Nov 25, 2010 7:59 pm

Re: Do you have to snag intermittent problems?

Post by helicopterray » Tue May 07, 2019 6:27 pm

If you notice an intermittent vibration, please report that. It can lead to a worse vibration if left unchecked.
---------- ADS -----------
  

digits_
Rank 10
Rank 10
Posts: 2182
Joined: Mon Feb 14, 2011 2:26 am

Re: Do you have to snag intermittent problems?

Post by digits_ » Tue May 07, 2019 6:48 pm

helicopterray wrote:
Tue May 07, 2019 6:27 pm
If you notice an intermittent vibration, please report that. It can lead to a worse vibration if left unchecked.
In my hypothetical example, everything gets reported to maintenance, but maintenance says it doesn't need to be snagged because the system works.

The reason is that the hypothetical company doesn't want to send an AME out to Lake-Fort-Buttfuck-Nowhere only to find out that there is nothing wrong with the plane.

So the intermittent problems get reported to maintenance, but don't end up in the book because nothing is broken after the flight. Does that change anything?
---------- ADS -----------
  

photofly
Top Poster
Top Poster
Posts: 7128
Joined: Tue Jan 18, 2011 4:47 pm
Location: Making aviation exhausting, everywhere

Re: Do you have to snag intermittent problems?

Post by photofly » Tue May 07, 2019 6:55 pm

You should read the TATC case I linked to two posts ago. It's exactly on point, and answers your questions.
Essentially, it's irrelevant what maintenance says, what's listed in the MCM is what determines what a defect is and the company has to follow it.\

For reference, the Small Operator Maintenance Control Manual, pre-approved for operators with three or fewer small aircraft, reads as follows:
11. DEFECT CONTROL

All defects shall be rectified before further flight of the aircraft, except as provided in this section. Where permitted by CAR 605.09 or CAR 605.10 as applicable, aircraft having outstanding defects may be operated subject to the following procedures: Where a Minimum Equipment List (MEL) has been approved and the list includes limits on the amount of time equipment may be inoperative, those limits apply. Where the MEL does not specify time limits, or where no MEL has been approved, the aircraft may be operated during the first 72 hours (calendar time) following discovery of a defect, at the discretion of the pilot in command. After 72 hours has elapsed, aircraft with outstanding defects shall not be operated without the authorization of the maintenance manager, which shall be recorded in the aircraft journey log. Where the authorization is given remotely (e.g. by telephone) the maintenance manager shall keep a record of the authorization, and identify the authorization with a control number. The journey log entry shall specify the reason for the deferral and the latest date by which the defect must be corrected. When the authorization is given remotely, the person making the journey log entry shall also include the identifying control number. No defect rectification shall be deferred for longer than 30 days (total calendar time) following discovery of the defect.

12. RECURRING DEFECT CONTROL

At intervals not exceeding one month, the maintenance manager shall review the aircraft technical records to detect any recurring defects. Any defect that has occurred three times or more within the past month or the past 15 flight segments (whichever period is the shortest) shall be reported to an AMO as a recurring defect. The AMO responsible for correcting a defect that has been identified as recurring, shall ensure that the corrective action includes a complete investigation of the affected system(s), taking into consideration all previous occurrences of the defect and the actions taken to correct it. The journey log entry for rectification of the defect shall indicate that a recurring defect investigation has been carried out.
---------- ADS -----------
  
Kirk: This is a dangerous mission. Likely, one of us will die. The landing party will be me, Spock, McCoy, and Ensign Ricky.
Ensign Ricky: Aw, crap.

corethatthermal
Rank 3
Rank 3
Posts: 184
Joined: Tue Feb 12, 2019 7:27 pm

Re: Do you have to snag intermittent problems?

Post by corethatthermal » Tue May 07, 2019 7:24 pm

There is NO technical description of a defect in TC CARS etc.
A place I worked at prior, I was given sh!t by the mechs for "writing it in the book" I responded why I bother, you just call it GTS. We can only fix it if they buy us parts. I said no problem, I will keep snagging it. Well we will keep putting GTS in the book. Well the next mx audit, it will come up as a "finding" amazingly they fixed it thereafter
Sadly, that may be the only recourse
---------- ADS -----------
  

BigQ
Rank 2
Rank 2
Posts: 88
Joined: Mon Sep 24, 2007 3:41 pm
Location: YUL-ish

Re: Do you have to snag intermittent problems?

Post by BigQ » Wed May 08, 2019 6:30 am

I always do. Sometimes just writing a snag as "for pilot information purposes only", so that others can make safe and well-informed decisions in the future. For example, TCAS resetting by itself in flight. Auto-stabilized radar showing a ton of ground clutter at 80nm scale, but not at 160 or 40nm. VNAV target path doing odd things for a few thousand feet's worth of descent, but easily fixed by inputing a fake need for engine anti-ice. Things like that. Nothing unsafe, but good to know for other pilots unfamiliar with the little quirks of each aircraft.

When in doubt, snagging, even if you know it will just get GTS'ed, or not trigger reports in the ACMS/FDM logs, is still safer than leaving it for the next guys and gals to figure it out. And it shows a pattern for pilots, mtce, and auditors, to follow.

If you are really concerned about your image with the rest of the company, leave a couple chocolates in the FD for the mechanics' enjoyment. I don't do it personally, but you'd be surprised the positive effect it has on everyone around you.
---------- ADS -----------
  

Heliian
Rank (9)
Rank (9)
Posts: 1487
Joined: Wed Apr 29, 2009 2:14 pm

Re: Do you have to snag intermittent problems?

Post by Heliian » Wed May 08, 2019 7:55 am

corethatthermal wrote:
Tue May 07, 2019 7:24 pm
There is NO technical description of a defect in TC CARS etc.
A place I worked at prior, I was given sh!t by the mechs for "writing it in the book" I responded why I bother, you just call it GTS. We can only fix it if they buy us parts. I said no problem, I will keep snagging it. Well we will keep putting GTS in the book. Well the next mx audit, it will come up as a "finding" amazingly they fixed it thereafter
Sadly, that may be the only recourse
From the journey log requirements: "Particulars of any defect in any part of the aircraft or its equipment that becomes apparent during flight operations"

We encourage people to write in defects, they need to be tracked and rectified.

Those small defects that quickly disappear are signs of an impending failure, that's why they have the recurring defect requirement, so you can't just keep returning it to service. There are still a couple companies out there with shoddy tracking and maintenance but any reputable operation will properly maintain their aircraft AND their logs.
---------- ADS -----------
  

co-joe
Rank 11
Rank 11
Posts: 3400
Joined: Mon Feb 16, 2004 2:33 am
Location: YYC 230 degree radial at about 10 DME

Re: Do you have to snag intermittent problems?

Post by co-joe » Thu May 09, 2019 6:54 am

If you don't snag it, the AME's can't fix it.
---------- ADS -----------
  

digits_
Rank 10
Rank 10
Posts: 2182
Joined: Mon Feb 14, 2011 2:26 am

Re: Do you have to snag intermittent problems?

Post by digits_ » Thu May 09, 2019 8:05 am

photofly wrote:
Tue May 07, 2019 6:55 pm
You should read the TATC case I linked to two posts ago. It's exactly on point, and answers your questions.
Essentially, it's irrelevant what maintenance says, what's listed in the MCM is what determines what a defect is and the company has to follow it.\
Thanks! Read it in detail and it does clarify a bit how the system works/thinks.
---------- ADS -----------
  

The Hammer
Rank 6
Rank 6
Posts: 406
Joined: Tue Mar 16, 2004 6:46 am

Re: Do you have to snag intermittent problems?

Post by The Hammer » Thu May 09, 2019 8:40 am

So I work for a large Canadian airline flying a 705 jet.
Thanks to way too many sensors it likes to give spurious flight control disagree faults (white status messages on EICAS) particularly after the start. This occurs because the sensors erroneously/momentarily defect a fault and the message won't clear even if it rectifies itself.

The SOP's and QRH reference resetting specific breakers and 99% when we follow the procedure this the white status message disappears. It happens often enough that I know the CB's by memory and the paint around them is worn.

Is this a defect or not?
---------- ADS -----------
  

Eric Janson
Rank 8
Rank 8
Posts: 800
Joined: Thu Feb 08, 2007 10:44 am

Re: Do you have to snag intermittent problems?

Post by Eric Janson » Thu May 09, 2019 9:32 am

The Hammer wrote:
Thu May 09, 2019 8:40 am
So I work for a large Canadian airline flying a 705 jet.
Thanks to way too many sensors it likes to give spurious flight control disagree faults (white status messages on EICAS) particularly after the start. This occurs because the sensors erroneously/momentarily defect a fault and the message won't clear even if it rectifies itself.

The SOP's and QRH reference resetting specific breakers and 99% when we follow the procedure this the white status message disappears. It happens often enough that I know the CB's by memory and the paint around them is worn.

Is this a defect or not?
No - a computer reset is an approved procedure by the manufacturer to allow you to clear nuisance warnings such as the one you describe.

You should have a list of approved resets - not all are allowed in all phases of flight.

However if the indication returns after a reset then it is a defect and needs to be written down. Usually the Engineers can see exactly which component is causing the issues.
---------- ADS -----------
  
Always fly a stable approach - it's the only stability you'll find in this business

MRP
Rank 2
Rank 2
Posts: 57
Joined: Thu Sep 18, 2008 7:36 am

Re: Do you have to snag intermittent problems?

Post by MRP » Thu May 09, 2019 4:39 pm

Eric Janson wrote:
Thu May 09, 2019 9:32 am
The Hammer wrote:
Thu May 09, 2019 8:40 am
So I work for a large Canadian airline flying a 705 jet.
Thanks to way too many sensors it likes to give spurious flight control disagree faults (white status messages on EICAS) particularly after the start. This occurs because the sensors erroneously/momentarily defect a fault and the message won't clear even if it rectifies itself.

The SOP's and QRH reference resetting specific breakers and 99% when we follow the procedure this the white status message disappears. It happens often enough that I know the CB's by memory and the paint around them is worn.

Is this a defect or not?
No - a computer reset is an approved procedure by the manufacturer to allow you to clear nuisance warnings such as the one you describe.

You should have a list of approved resets - not all are allowed in all phases of flight.

However if the indication returns after a reset then it is a defect and needs to be written down. Usually the Engineers can see exactly which component is causing the issues.
Sounds like the Embraer, lots of computer resets. At my company when we do a computer reset due to an EICAS or ECAM fault it is required to be written as a snag in the logbook, then signed as resolved by the pilot who did the reset. Approved resets are considered elementary work and can be signed off by the pilot so there is no need to involve maintenance. This is very important for tracking purposes. Any more than 3 resets in the last 7 days require an inspection by maintenance.
---------- ADS -----------
  

Post Reply

Return to “General Comments”