crash landing Cockpit voice recorder survived fiery Philly crashbut stopped taping years ago Heroic work to recover and repair a CVR. Nate Anderson Mar 12, 2025 5:39 pm | 15 A cockpit voice recorder, in pristine condition. Credit: NTSB Story textSizeSmallStandardLargeWidth *StandardWideLinksStandardOrange* Subscribers only Learn moreCottman Avenue in northern Philadelphia is a busy but slightly down-on-its-luck urban thoroughfare that has had a strange couple of years.You might remember the truly bizarre 2020 press conference heldfor no discernible reasonat Four Seasons Total Landscaping, a half block off Cottman Avenue, where a not-yet-disbarred Rudy Giuliani led an farcical ensemble of characters in an event so weird it has been immortalized in its own, quite lengthy, Wikipedia article.Then in 2023, a truck carrying gasoline caught fire just a block away, right where Cottman passes under I-95. The resulting fire damaged I-95 in both directions, bringing down several lanes and closing I-95 completely for some time. (This also generated a Wikipedia article.)This year, on January 31, a little further west on Cottman, a Learjet 55 medevac flight crashed one minute after takeoff from Northeast Philadelphia Airport. The plane, fully loaded with fuel for a trip to Springfield, Missouri, came down near a local mall, clipped a commercial sign, and exploded in a fireball when it hit the ground. The crash generated a debris field 1,410 feet long and 840 feet wide, according to the National Transportation and Safety Board (NTSB), and it killed six people on the plane and one person on the ground.The crash was important enough to attract the attention of Pennsylvania governor Josh Shapiro and Mexican President Claudia Sheinbaum. (The airplane crew and passengers were all Mexican citizens; they were transporting a young patient who had just wrapped up treatment at a Philadelphia hospital.) And yes, it too generated a Wikipedia article.NTSB has been investigating ever since, hoping to determine the cause of the accident. Tracking data showed that the flight reached an altitude of 1,650 feet before plunging to earth, but the plane's pilots never conveyed any distress to the local air traffic control tower.Investigators searched for the plane's cockpit voice recorder, which might provide clues as to what was happening in the cockpit during the crash. The Learjet did have such a recorder, though it was an older, tape-based model. (Newer ones are solid-state, with fewer moving parts.) Still, even this older tech should have recorded the last 30 minutes of audio, and these units are rated to withstand impacts of 3,400 Gs and to survive fires of 1,100 Celsius (2,012 F) for a half hour. Which was important, given that the plane had both burst into flames and crashed directly into the ground.Cockpit voice recorders are amazingly hardened bits of tech. They are often kept in the back of the plane, so as to better survive a crash, but their audio comes from a microphone usually found on the instrument panel above and between the two pilot stations. The utility of this recording does not come just from what the pilots might say; the sound of a stall warning indicator or landing gear retraction or engine noise could each allow investigators to infer things about the flight's last moments.The NTSB eventually found the cockpit voice recorder of the Learjet 55, which was inside the impact crater and buried "under 8 ft of soil and debris." The unit was pretty beat upor, as the government puts it, displayed "significant impact-related damage as well as liquid ingress." So NTSB sent the device to its Vehicle Recorders Laboratory in Washington, DC, hoping to salvage some of the audio. The CVR after recovery from the north Philly crash site. After "extensive repair and cleaning," technicians were able to listen to the tape... and they found to their chagrin that it contained nothing related to the accident. In a preliminary report on the plane crash, released last week, NTSB investigators said that "the CVR did not record the accident flight and during the audition it was determined that the CVR had likely not been recording audio for several years." Even the most hardened, comically over-specced devices can failand sometimes it's not even the fire, the impact, or the "liquid ingress" that brings them down.Still, NTSB is not out of options. The Learjet contained another important piece of tech: an Enhanced Ground Proximity Warning System (EGPWS) computer. The device may contain crash data in nonvolatile memory, and it has been shipped off to its manufacturer to see what, if anything, can be recovered.Nate AndersonDeputy EditorNate AndersonDeputy Editor Nate is the deputy editor at Ars Technica. His most recent book is In Emergency, Break Glass: What Nietzsche Can Teach Us About Joyful Living in a Tech-Saturated World, which is much funnier than it sounds. 15 Comments