Lightspeed unveiled its newest pilot headset, the Delta Zulu, in September 2022, and since then I was able to test it in a typical piston airplane and in a single-engine turboprop. The Delta Zulu is similar in size and configuration to Lightspeed’s Zulu 3 but adds more active-noise canceling (ANR) technology and a unique audio equalization system as well as a carbon monoxide sensor.
For comparison purposes during these flights, I tried the Delta Zulu and a Bose A20 ANR headset. It is admittedly a somewhat subjective test, but I found the Delta Zulu to be quite comfortable and with excellent noise-canceling. Either headset does a great job of canceling noise, but the added features of the Delta Zulu might make it a more attractive purchase for some pilots.
This iteration of the Delta Zulu includes the first of what might be multiple sensors that add capabilities and make the headset a platform rather than just something that enhances hearing in noisy cockpits.
Lightspeed’s Kanari “smart alert technology” sensor measures carbon monoxide (CO) levels in the wearer’s vicinity. The headset’s audible alerts warn when it detects CO above caution and critical levels (10-50 and 50-100 ppm, respectively), but pilots can also view CO levels and history on the Lightspeed app.
With the HearingEQity audio equalization system, pilots can run a 12-frequency hearing test while wearing the Delta Zulu headset connected via Bluetooth to the app, obviously not while flying. Once completed, the audio equalization system sets the hearing level in each ear cup “to create your individual hearing profile to compensate for any hearing variations between ears,” according to Lightspeed.
The hearing test assesses the user’s hearing, running each ear through 12 different low-to-high frequencies. For each frequency, the user has to adjust a volume slider in the app until the sound is barely perceptible.
As I suspected, my hearing drops off at the higher frequencies, and this proved almost universal in men that I tested with HearingEQity. Women who tried the test generally had better hearing at the higher frequencies. One couple I tested clearly illustrated why the husband couldn’t hear the wife and vice versa, as their optimum frequencies were completely opposite.
I flew with the Delta Zulu headset on two flights, one in a Cessna 172 and another in a Daher Kodiak 900 single-engine turboprop. On both flights, I swapped between the Lightspeed and a Bose A20 ANR headset to try to compare them. As mentioned, I wasn’t able to perceive a distinct difference in hearing quality between the two headsets. ATC communications were clear with both. The Lightspeed headset did feel like it had less clamping pressure on my head, and I liked the way it easily accommodated my eyeglasses without feeling like they were being forced against my head. Having the Kanari carbon monoxide detector along for the ride was a clear bonus and makes me wonder why proper detectors aren’t mandatory on all piston-powered airplanes. Or at least on airplanes with heater muffs wrapped around exhaust pipes, which is the typical setup for cabin heaters on single-engine airplanes.
The Delta Zulu is priced at $1,099, $200 more than the Zulu 3. While some potential buyers might opt for a Bose headset because their flight operation (generally Part 121 airlines) require that pilots use headsets manufactured to an FAA Technical Standard Order (TSO), Lightspeed points out that this should not be necessary.
According to Lightspeed, “The authorization pertains to design and production approval. Using a TSO headset is not an FAA requirement for any type of civil operation including Part 91, 121, or 135 operations and only specifies a ‘minimum performance standard.’ Where the confusion can sometimes occur is that individual operators may choose to require the presence of a TSO headset either ‘available to the pilot’ or ‘worn by the pilot.’”
In any case, Lightspeed has chosen not to undergo the expensive process of obtaining TSO approval of its headsets because it feels that this is an unnecessary step. According to the company, “All Lightspeed headsets are tested to FCC and CE certifications, internal environmental standards, Apple MFi program standards (if required), and meet performance requirements of the FAA to be used in any civil aircraft. A Lightspeed headset will perform exactly the same as any TSO-certified headset in emergency situations. For example, if the batteries die during flight, there will still be uninterrupted communication (fail-safe mode). If there is a complete power failure in the aircraft, the Bluetooth feature will enable you to use a cellular or satellite phone to contact ATC—depending on which you have on board.”