Lab: Southern Airways Flight 932 — A CVR Investigation

Overview⌗

Session Date: Thursday, April 16, 2026
Duration: ~65 minutes

Objective: Analyze the CVR transcript from Southern Airways Flight 932 — a 1970 crash that killed 75 people, including the Marshall University football team. You will read and interpret the official NTSB transcript, form forensic hypotheses about two unidentified sounds, discover how CVR data corrected a proposed investigative explanation, and synthesize what you have learned this week into a four-case comparison.

What to submit: One Word document (.docx) with each question copied in followed by your answer, organized by exercise number, submitted to the D2L assignment for Week 14.

Forensic caution: Use cautious language throughout — “consistent with,” “suggests,” or “the evidence does not support.” Do not overclaim or assign blame beyond what the evidence shows.

Background⌗

On November 14, 1970, Southern Airways Flight 932 — a DC-9 on charter carrying the Marshall University football team, coaches, staff, and boosters — attempted an instrument approach — a standardized landing procedure that guides pilots onto a runway using cockpit instruments and radio navigation rather than visual reference to the ground, used when visibility is too low to see the runway until the final seconds of descent — to Huntington Tri-State Airport in West Virginia. The weather was poor: ceilings ragged between 400 and 600 feet, visibility five miles, rain, fog, and smoke. The aircraft was 350 feet lower than the crew believed. It struck treetops on the west face of a hill while attempting to climb. All 75 people aboard were killed.

The cockpit voice recorder was recovered from the wreckage. It provided the only real-time record of what the crew experienced in the final minutes of flight.

A note on this transcript: CVR audio from this era is federally protected and has never been publicly released. What you are reading is the NTSB’s official transcript — a factual document that records words and sounds only, without interpretation. Interpreting those words and sounds is your job.

Primary source: Bruce Epperson, “’…6 Seconds loud, undifferentiated noise [recording ends]’: A Forensic Audio Analysis of the CVR Recording of Southern Airways Flight 932,” ARSC Journal 50, no. 1 (Spring 2019): 79. (PDF)

The Transcript⌗

Download the PDF and open it now. The CVR transcript runs across pages 12–13.

The speaker codes used throughout are:

• PLT — Pilot in command
• COPLT — Copilot
• JMPST — Charter supervisor, riding in the jumpseat (observer seat behind the pilots)
• HUNT — Huntington Tri-State Approach Control (air traffic controller, via radio)

Part 1: Reading the Transcript (~15 minutes)⌗

Exercise 1: Transcript Orientation⌗

Turn in — Word doc questions:

1. The transcript has three speaker codes: PLT, COPLT, and JMPST. Based on Tuesday’s lecture, which CVR channel most likely captured each speaker? (Not all four channels appear in every transcript — explain your reasoning.)
2. The non-speech entries divide into two categories: procedural sounds (landing gear, outer marker tone, flap selector) and the two unidentified sounds at the end. List every non-speech entry in the transcript and write one sentence for each describing what it tells investigators about the state of the aircraft at that moment.
3. The note “[Recording jumps forward seven minutes]” is not a gap in the original recording — it is an editorial decision in the published transcript. Why might NTSB transcribers choose to omit several minutes of cockpit audio from a published accident report? What does that decision tell you about what those seven minutes likely contained?

Part 2: The Unidentified Sounds (~15 minutes)⌗

At 7:35:20 and 7:35:21 — just six seconds before the recording ends — two unidentified sounds appear in quick succession. When investigators first analyzed this recording, they did not know what these sounds were.

Stop here before reading further. Answer Exercise 2 before you look at the reveal below.

Exercise 2: Form a Hypothesis⌗

Turn in — Word doc questions:

1. Write your best hypothesis for what each unidentified sound was. Consider: where is the aircraft at this exact moment in the approach? What has just happened in the transcript? What sounds does a DC-9 produce during this phase of flight? State your hypothesis and explain your reasoning in 2–4 sentences.
2. At 7:35:23, the copilot calls out “Hundred and twenty-six.” In context, this is an airspeed callout — 126 knots, just below the crew’s target approach speed of 130 knots (“the bug”). How does knowing the aircraft is still at near-normal approach speed at the moment the sounds begin help narrow down what the aircraft was doing?
3. Ten seconds before the unidentified sounds, the jumpseat passenger said “I bet it’ll be a missed approach.” A missed approach is when pilots abort a landing attempt and climb away from the runway. If the unidentified sounds were consistent with the crew initiating a missed approach, what specific aircraft actions would you expect to be occurring at that moment?

Part 3: How CVR Data Corrected an Investigative Error (~15 minutes)⌗

The unidentified sounds solved one question, but left a larger one open: why was the aircraft 350 feet lower than the crew believed? The NTSB initially proposed an explanation — and CVR data is what showed that explanation was wrong.

The initial hypothesis: Investigators considered whether the crew had been using their radar altimeters instead of their barometric altimeters. A radar altimeter measures height above the terrain directly below the aircraft. A barometric altimeter measures height above sea level, calculated from air pressure. In rugged terrain like the hills around Huntington, the two can differ substantially. If the crew relied on a barometric altimeter set for flat terrain at sea level, it could show them at 400 feet above the ground while the actual terrain had risen beneath them. This would constitute pilot error.

Exercise 3: The Corrected Hypothesis⌗

Turn in — Word doc questions:

1. If the crew had been misreading their altimeters and were actually lower than they believed, what would you not expect to find in the final seconds of the CVR transcript? How does the presence of Unidentified Sounds #1 and #2 challenge the altimeter error hypothesis?
2. Technical modeling by the aircraft and instrument manufacturers ultimately showed that the altimeter error hypothesis was incompatible with the CVR and flight data recorder evidence combined. The NTSB listed the probable cause as “unknown” — not pilot error — and recommended that the FAA mandate ground proximity warning systems on commercial aircraft. What does this outcome tell you about the role CVR evidence can play when it cannot identify a cause but can rule out a proposed one?
3. In USAir 427, non-speech sounds on the CVR identified the cause of the crash (a rudder power control unit failure). In Southern Airways 932, non-speech sounds ruled out a false explanation. Write one sentence for each case describing the specific forensic role the non-speech audio played.

Part 4: Synthesis (~10 minutes)⌗

Exercise 4: Four Uses of CVR Audio⌗

This week’s lecture covered three accidents where CVR analysis was decisive. Today you have examined a fourth. Using all four cases, complete the table below. Write 1–2 sentences in the final column for each row.

Turn in — Word doc: The completed table with your answers in the final column.

Part 5: Forensic Write-Up (~10 minutes)⌗

Exercise 5: Expert Summary⌗

Write one paragraph (5–8 sentences) suitable for inclusion in an accident investigation report. Your paragraph should address all three of the following:

• What the CVR transcript of Southern Airways 932 shows about the crew’s situation and actions in the final minutes of flight
• What the unidentified sounds revealed, and how that evidence contributed to — or limited — the investigation’s conclusions
• What this case illustrates about the forensic value of CVR evidence beyond speech recording

Turn in — Word doc: One paragraph using cautious forensic language throughout. Do not simply restate the case facts — explain the reasoning behind the conclusions as if writing for a reader who has not seen the transcript.

Submission Checklist⌗

Before you submit, confirm you have:

• One Word document (.docx) with each question copied in, followed by your answer, organized by exercise number
• Exercise 1: Every non-speech entry listed with a one-sentence description
• Exercise 2: Your hypothesis written before reading the reveal — not after
• Exercise 3: One sentence each for USAir 427 and Southern Airways 932 (question 3)
• Exercise 4: All four table rows completed
• Exercise 5: Forensic paragraph with cautious language throughout

Submit to the D2L assignment for Week 14.