Source: https://bruceair.wordpress.com/2017/11/
Timestamp: 2019-04-23 00:09:30+00:00

Document:
Many pilots struggle with the regulations and procedures to follow when a preflight inspection or other before-takeoff check reveals a burned-out position light, a non-functional autopilot, or other inoperative equipment. Here’s a basic guide to help you through the thicket of FAA regulations and policies.
Simply put, as PIC, you–not your mechanic, or the FBO from which you rent an airplane, or the partner(s) with whom you share an aircraft–are responsible for determining whether the aircraft you’re about to fly is legally airworthy and safe to operate.
Can you fly the airplane?
How can you comply with the applicable FAA regulations?
Many pilots think that such minor malfunctions require nothing more than recalling the required equipment regulations for day or night, VFR or IFR flight (14 CFR §91.205), and, if necessary, putting an “inoperative” sticker near the appropriate switch or gizmo before taking off.
The proper procedure, however, involves methodically tracing your way through several FAA regulations and references, including the aircraft flight manual (AFM) and associated aircraft documents.
Here’s a flow chart that outlines the basic process described in §91.213.
Throughout the following discussion, note that if the defective or inoperative item is required at any of the decision points, maintenance or obtaining a ferry permit (technically a Special Flight Permit) is required before you can fly.
Begin by determining whether inoperative item is required under the basic regulations for VFR or IFR flight during the day or night (§91.205), including key engine instruments, altimeter, airspeed indicator, magnetic direction indicator, and so forth. Operations at night and under IFR (regardless of prevailing weather conditions) require additional instruments and equipment, such as lights (night) and radios and gyroscopic instruments (IFR).
If the item isn’t specifically listed in §91.205(a)-(d), next determine if it’s required by the AFM/POH equipment list or kinds of operations list (examples below).
If the item isn’t required by those equipment lists, or if you have an old AFM/POH that doesn’t include equipment lists, next confirm that the item is not required by the aircraft’s type certificate data sheet (TCDS). You can download PDF versions of TCDS from the FAA website, here. These data sheets are usually long and not easy to read, but you can search the PDF for your aircraft to help you locate specific model/serial numbers or items.
If the item isn’t required by the TCDS, review any STC supplements that apply to your aircraft. For example, if you’ve installed new avionics or electronic instruments in the panel, the STC under which that equipment was installed may contain specific limitations, such as additional sources of electrical power.
Next, you must confirm that the item isn’t required by an airworthiness directive (AD). You can find ADs on the FAA website, here. Again, ADs can be difficult to parse. If you have questions, it’s best to consult a maintenance technician. Aircraft type and owner clubs are also good sources of information about ADs.
If you’ve answered “no” at each step of the process, you can proceed–but you must follow the proper procedure to deactivate or remove and then placard the item. And you must record the discrepancy and action taken in an appropriate record (§91.405 and §43.11).
Options at this point include disabling a switch, pulling and collaring a circuit breaker, or removing the equipment following the appropriate procedure. If the inoperative item is controlled by anything other than a simple switch, it’s best to consult a maintenance technician.
Finally, as PIC, you must determine that the aircraft is safe to operate under the conditions expected for the flight.
Note that you can’t continue to operate indefinitely with inoperative/defective equipment. See §91.405(c) and the De Joseph letter (2017) from the FAA chief counsel. In general, at the next required inspection the item must be repaired, replaced, or removed and the action properly documented by a maintenance technician.
The process described here is cumbersome, especially when you’re away from your home airport without easy access to references and technical advice.
But here’s a good rainy-day project. Create a list of equipment in your aircraft that isn’t clearly required by §91.205 for a typical day or night VFR flight, such as lights, avionics, accessories (seats, cabin heat, power plugs, speakers, etc.). Follow the flow chart, consult the resources described here, and note whether those items would be necessary for a flight under those circumstances.
If you fly IFR, add or note the equipment, beyond the basics in §91.205, that is required by the documents for your aircraft–regardless of the weather–to operate under those rules.
Keep those lists in your aircraft (or on your tablet or phone) so that you can quickly and easily determine whether you can proceed.
I’ve recently noticed questions popping up about the letters Z, Y, X appearing in the titles of instrument approach procedures. Titles that include “-A,” “-B,” or “-C” are familiar–they designate procedures that have only circle-to-land minimums, such as the VOR-A at Olympia, WA (KOLM). But letters from the other end of the alphabet puzzle many pilots.
ILS Y RWY 27 and ILS Z RWY 27 at Yakima, WA (KYKM) and the RNAV (GPS) W RWY 27 and RNAV (GPS) X RWY 27 at the same airport.
ILS OR LOC/DME Y RWY 16R and ILS Z OR LOC/DME Z RWY 16R at Snohomish County–Paine Field (KPAE) north of Seattle.
As noted above, approaches to the same runway can be labeled Z, Y, or X… for several reasons.
For example, consider the ILS RWY 27 at KYKM, which is published as both the ILS Y RWY 27 and ILS Z RWY 27.
The Z version requires a non-standard climb gradient of 250 ft/nm on the missed approach procedure (see the note in the plan view), but it provides a DA of 1268 (200 AGL) with RVR 2400.
The DA on the Y version of the approach is 1725 (657 AGL) with visibility of 2 sm. So you can go much lower and to the equivalent of 1/2 sm visibility if you can achieve the steeper climb gradient on the miss.
There are two versions of the ILS RWY 16R–but for a different reason–at Snohomish County–Paine Field (KPAE) north of Seattle.
Both procedures offer the same basic DA and visibility minimums (although the Z version allows a reduction to RVR 1800 with a flight director, autopilot or HUD). But the FAF (ITIPE) for the Y edition is 4.4 nm from the PAE VOR.
The Z version, which also has published minimums for category C and D aircraft, has a FAF (JUGBA) at 7.6 nm from the VOR.
If you’re flying a typical light GA aircraft, the Y version is much more efficient, while the Z version is better suited to jets (like the shiny new Boeings emerging from the factory at KPAE) that need more room to get established on final.
As pointed out earlier, Z, Y, and X versions of the same basic procedure may require different equipment or missed approach segments. For example, using your favorite chart-viewing app, compare the ILS Y or LOC RWY 20 and the ILS Z or LOC/DME RWY 20 at Walla Walla, WA (KALW).
The key to flying such approaches is a careful review of the entire procedure, including notes lurking on the chart. When you contact ATC, it’s also important to request the specific procedure–including the letter–that you want to fly.
And, if you’re using an IFR-approved GPS–even for situational awareness or to act as a substitute for DME or ADF when flying a ground-based approach– ensure that you load the correct procedure and verify the key fixes before you begin flying the approach.
The final rule is set for publication on June 27, 2018 (see this notice at the Federal Register). I’ll provide a summary here at BruceAir.
You can read more about the NPRM published in May 2016 at my blog, here.
My feature about stall and spin training in the November issue of AOPA Flight Training is now available online, here.

References: §91
 §91
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 §43
 §91
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