FAA Field Approval For A Light Bulb?

Are you flippin’ kidding me? That’s the family-safe version of my response when a shop wouldn’t install a Whelen PAR36 Parmetheus drop-in LED in a reader’s airplane without first lobbying FAA field approval. The aircraft, a first-gen Cirrus SR22, has a traditional incandescent landing/taxi lamp mounted in the nose bowl. Replacing it with the Whelen drop-in is a matter of accessing the lamp, unscrewing it from the mount, pulling off the connector and installing the new LED lamp in reverse order. Even a caveman could do that.

The tough part comes when it’s time to endorse the installation in the logbooks. The snag: While Whelen has a sizable AML/STC (approved model list supplemental type certificate) for its drop-in PAR36/PAR46-sized assemblies, there isn’t an across-the-board installation approval in place. In other words, if the aircraft isn’t on Whelen’s AML (and the Cirrus isn’t), the installation will likely require a field approval.

I contacted Whelen to get the skinny. According to Whelen’s Aviation project manager Greg Ginnetti, an IA might determine that the Whelen LED can be installed on an aircraft that’s not on the AML by using the basis of Whelen’s lengthy PMA. But without a specific aircraft type approval, Ginnetti finds it difficult to envision an IA signing it off without formal FAA interaction.

Ginnetti envisioned correctly. I spoke with several IAs and FAA repair stations around the country and every one of them told me that without an STC, it would have to lobby field approval before installing the lamp. In fact, one actually tried to gain approval for installing a Whelen LED landing light on a light twin, but was unsuccessful because the inspector didn’t have enough previously approved data to determine the installation would be airworthy.

What is considered previously approved data? It depends on the inspector that is signing it off. One supporting document could be an FAA form 337 that has been signed by another inspector or ACO, as long as the installation was accomplished in the same make and model aircraft.

The key is to select a lamp based on the availability of approval data. It could save some legwork during the preparation stages of a field approval, while ultimately saving you money. That’s because you’ll pay for the time it takes a shop to gain approval.

For instance, AeroLEDs offers useful regulatory guidance right on its website, including previously approved 337 forms that shops and technicians can use when preparing a field approval package. AeroLed says that its Sunspot 36LX landing and taxi lights can be installed with just a logbook entry if you can install the light in an existing mount and use the existing wires, switches and circuit breakers. But this is for basic functionality.

The company’s Sunspot 36HX landing and taxi lights (these have pulse or so-called wig-wag functionality) can be installed with the pulse function enabled only in a Cessna 185 under its STC, or in other aircraft models by submitting a 337 form that uses the Cessna 185 STC as a basis for approval. This is where it gets tricky. Most inspectors will argue that the Sunspot’s approval in a Cessna 185 has little if anything in common with its approval in a Piper Seneca, for example.

One inspector told me that it might be easier to approve a simple installation that includes a TSO’d lamp, but stressed that if there are any structural modifications made to the mounting assembly, changes to wiring and changes to the control switch, the field approval process must be used.

What is that process, exactly? It begins by following AC 43-210, which describes the standardized procedures for requesting field approvals for certificated products. It describes the field approval process, the particular data that supports making an alteration or repair, while outlining the purpose and uses of the Aircraft Flight Manual Supplements (AFMS) and Instructions for Continued Airworthiness (ICA).

Think of a field approval as a one-time STC. The advisory circular also gives instructions for completing the field approval checklist and shows a sample compliance checklist format that shops and technicians should use during the process.

The typical field approval is essentially a three-step process, whether it’s the installation of a landing light or a major avionics system. There is research, the submission of the field approval data package and then performing the alteration. Sadly, many inexperienced shops make the mistake of following the process in reverse order; first installing the device and then requesting field approval. This is by far the easiest way to turn an otherwise airworthy aircraft into a hangar queen while the shop waits for FAA approval. I’ve seen aircraft sit for months while the shop waits for a decision.

It pays to do your homework before making the purchase. In the case of drop-in LED landing lights, FAA approval could end up costing more than the lamp itself.

Larry Anglisano
Editor in Chief Larry Anglisano has been a staple at Aviation Consumer since 1995. An active land, sea and glider pilot, Larry has over 30 years’ experience as an avionics repairman and flight test pilot. He’s the editorial director overseeing sister publications Aviation Safety magazine, IFR magazine and is a regular contributor to KITPLANES magazine with his Avionics Bootcamp column.