Deactivating Equipment

[groundpointsix]

For the purposes of 91.213, what constitutes deactivating equipment? Is it enough to switch it to the off position? Pull the circuit breaker? Pull and collar the circuit breaker? Smash it with a hammer? I assume the FAA has put this in an AC, but I'm too lazy to look. Thanks.

 

[paulsalem]

Smash it with a hammer?

Do you work in the maintenance shop 2 hangers down???

 

[midlifeflyer]

Good luck with getting a good answer. The AC is 91-67.

While it defines "deactivation" simply as "to make a piece of equipment or an instrument unusable to the pilot/crew by preventing its operation," it later tell us

==============================
A certificated pilot can accomplish deactivation involving routine pilot tasks, such as turning off a system. However, for a pilot to deactivate an item or system, that task must come under the definition of preventive maintenance in FAR Part 43, Subpart A.
==============================

So whether you can, say, "deactivate" a DG for 91.213 purposes by covering it, is one of the great unanswered questions in aviation. Covering it "makes it unstable" but messing with the DG and gyro system is hardly "preventive maintenance"

 

[nosehair]

==============================
A certificated pilot can accomplish deactivation involving routine pilot tasks, such as turning off a system. However, for a pilot to deactivate an item or system, that task must come under the definition of preventive maintenance in FAR Part 43, Subpart A.
==============================

Yikes! I've not read this AC nor can I live with the concept of the second sentence. However, the first sentence works for me in "deactivation involving routine pilot tasks, such as turning off a system". That would work for things like lights and radios not required by FAR for the flight. It does indicate that a vacuum instrument not required for the flight would need to be "deactivated" by a mechanic.

 

[bafanguy]

If the original questioner is operating with a published MEL for his type airplane, does the intro/preamble contain any guidance on how this deactivation is done ?


The only MEL's I've used were 121, but perhaps the idea is the same for Part 91 ( never seen a Part 91 MEL ). The intro had very specific guidance on how inop'ing was to be done and by whom. We had the option of "pilot placarding" and it worked well. Pilots could inop anything that didn't require reference to the MM or opening access panels.

The MEL is a legal, non-negotiable minefield and, in using it, you are leaving a paper trail a blind man could follow. Y'all be careful out there...

 

[groundpointsix]

No MEL, just 91.213. Aircraft in question is a C172 and the inoperative equipment is the transponder. By the AC's definition it seems to be that simplying putting it in the "OFF" position is enough to deactivate it. However, I'm not sure that this is an item that would require a log entry. Flipping a switch doesn't seem to meet the definition for "preventitive maintenance." The AC makes it sound like I'd have to make an entry for anything I do; the regulation itself makes it sound like I don't.

 

[MTpilot]

Just yank the sumbitch out!

 

[USMCmech]

It does indicate that a vacuum instrument not required for the flight would need to be "deactivated" by a mechanic.

Nope, you can do it if you have your PPL.

Preventative Maintence:

FAR 43 appendix A, para c (21) "Replacing any hose conection except hydraulic conections."


In my view that gives you enough coverage to take a vacum line off the back of a gyro. Tape over the front, write "INOP" on the tape, and you're set.

This would definatly require a Maint logbook entry.

3/14/05 1586 TTAF
Removed and capped vacum line from DG due to malfunction. Placarded as INOP.
Joe Schmoe PPL12345678


I would recomend having an A&P do the reinstalation, however.

 

[avbug]

Hold on there, folks. Some dangerous advice being bantied about, and not at all accurate. First of all, the advisory circular AC 91-67 is not an authorization to do anything. Second of all, 14 CFR Part 43, Appendix A is also NOT an authorization to do anything, and frequently much it cannot be accomplished as preventative maintenance, and without specialized equipment, current maintenance publications for the component in question, and more.

AC 91-67, Chapter 1, Paragraph 7:

b. The operator must evaluate any proposed deactivation to assure there is no adverse effect that could render another system less than fully capable of its intended function.
(1) A certificated pilot can accomplish deactivation involving routine pilot tasks, such as turning off a system. However, for a pilot to deactivate an item or system, that task must come under the definition of preventive maintenance in FAR Part 43, Subpart A.
(2) If the deactivation procedures do not fall under preventive maintenance, a properly certificated maintenance person must accomplish the deactivation. The maintenance person must record the deactivation in accordance with FAR § 43.9 (figure 1, Sample Maintenance Record Entries.).
c. Placarding can be as simple as writing the word "inoperative" on a piece of masking tape and attaching it to the inoperative equipment or to its cockpit control. Placarding is essential since it reminds the pilot that the equipment is inoperative. It also ensures that future flightcrews and maintenance personnel are aware of the discrepancy.

A pilot can accomplish certain items of preventative maintenance as outlined in Appendix A of Part 43, but only if they do not involve complex assembly operations. A pilot who elects to do these preventative maintenance items is still subject to all the performance and record keeping requirements that any certificated mechanic is subject to, and to all of Part 43. This includes using the proper calibrated tools called our for by the appropriate maintenance documents, and having the current maintenance publications for each aircraft, appliance or component on hand. The pilot must also do enough research to find out of the intended operation is affected by an airworthiness directive, or if additional documentation such as an existing Form 337 or an STC applies.

Deactivating the transponder in the 172 might be accomplished by turning it off, but suppose there are additional problems. Perhaps a short internally or in the wiring harness. Merely turning off the device won't cut it in that case. Removal of the radio from the stack might be accomplished, but then the weight and balance documentation needs to be properly ammended.

Pulling the circuit breaker for the transponder might be appropriate, but what else is served by that breaker? How do you know, and do you have current electrical diagrams for the aircraft on hand? If not, you can't pull that breaker and operate with it in that condition. You'll need to reference the appropriate document and page number in your maintenance record entry describing what you've done, and the authorization to do it. Merely because it's found in Appendix A of Part 43, is not authorization to do any maintenance item. Where does the manufacturer say you can do it, and describe how you can do it?

As for removing vacum lines, a pilot has no business disconnecting plumbing behind the panel. Did you cap the line when you were done, and can you do that? In most cases, no, you can't. How do you cap the line if you can, and how do you seal the instrument? You can't just leave it open. Do you carry capplugs and the appropriate aluminum AN hardware, or were you just planning on sticking an old bolt in the end of the hose?

As most vacum systems serve several instruments, by disconnecting the hose on one instrument, you've disconnected them all; the airflow passes from one to the other. You've also opened the system for contamination, and bypassed the filter, making the entire system unairworthy, as well as questionable for future operation. Still don't think it's a complex assembly? What documents apply to your action, and do you have them all? You're not only going to need documents for the aircraft, but for the instruments by the individual component manufacturers. Do you have those in their most current issued form? If not you can't perform the work.

Do you have the specific tools called our for in the latest publications? If not, you can't perform the work. If the work calls for a particular hose clamp or fitting to have a particular torque, do you have a torque wrench, adapter, torque screwdriver or the necessary implements to meet the manufacturer requirements? Are they current and calibrated, and can you show it? If not, you can't do the work. Have you done the work before? If not, you can't do the work. Do you know what the effects and outcome of what you're doing will be, how it will affect other systems, or other parts of the same system, any additional electrical, hydralic, pneumatic, or mechanical loads it might cause, how it strengthens or weakens the surrounding structure, etc? If not, you can't do it.

Now I have a number of tool boxes, roll-aways, top boxes, carts, and cabinets, shadowed and filled with expensive tools, many specialty items, measuring implements, calibrated torque wrenches and screwdrivers, etc. There are a lot of functions that I can't do either, nor would I attempt, including at times things found in Appendix A as preventative maintenance. Sometimes merely because I don't have all the publications on hand. Or I may be missing a specific tool.

You find authorization in Appendix A to change an oil filter. Sounds simple enough. But many light airplanes have an AD applicable for the oil filter adapter. Every time you check that filter, the AD must be accomplished. The oil filter adapter uses a special crowsfoot adapter, and a torque check must be made (or in some cases, verification visually that the adapter nut is secure). The AD requires a signoff. A pilot attempting to change an oil filter is then subject to having the current researched and available, the engine manufacturers current maintenance manual, the oil filter adapter publication, the aircraft manufacturer's current maintenance manual, a calibrated torque wrench, the proper adapter, torque seal, safety wire pliers, a 7/8 wrench, .032 safety wire, and prior experience performing the job, just to start.

Never assume that merely because a regulation says something, it's everything published on the subject, or contains every requirement.

Deactivation in many cases is far more complex than simply flipping a switch and sticking a bit of masking tape up that says "inop."

The foregoing has not discussed the necessity for proper maintenance record entries, which is an additional full subject on it's own. Just be aware that what you often see is the tip of the iceberg, despite the fact that you are responsible for the entire chunk of ice.

 

[A Squared]

You find authorization in Appendix A to change an oil filter. Sounds simple enough. But many light airplanes have an AD applicable for the oil filter adapter. Every time you check that filter, the AD must be accomplished. The oil filter adapter uses a special crowsfoot adapter, and a torque check must be made (or in some cases, verification visually that the adapter nut is secure). The AD requires a signoff. A pilot attempting to change an oil filter is then subject to having the current researched and available, the engine manufacturers current maintenance manual, the oil filter adapter publication, the aircraft manufacturer's current maintenance manual, a calibrated torque wrench, the proper adapter, torque seal, safety wire pliers, a 7/8 wrench, .032 safety wire, and prior experience performing the job, just to start.

I have that AD in front of me. It is pretty clearly stated that once the adapter has been inspected as per the AD, the torque of the adapter nut checked, and Torque putty applied to the adapter nut, subsequent inspections at filter change require only an inspection of the torque putty. The AD further states in no uncertain terms that this inspection of the torque putty may be done by the pilot.

from the AD:

(d) Repetitive inspections of the torque putty as required by this AD may be performed by the owner/operator holding at least a private pilot certificate as authorized by section 43.7 of the federal aviation regulations (14 CFR 43.7), and must be entered into the aircradt records showing compliance with this AD in accordance with section 43.11 of the Federal Aviation Regulations (14 CFR 43.11).