From c40193824567e2d3fe01d1854382c44fadc0a636 Mon Sep 17 00:00:00 2001
From: Matthias Nott <mnott@mnsoft.org>
Date: Fri, 10 Apr 2026 09:48:50 +0200
Subject: [PATCH] Improve exam questions: fix errors, add diagrams, enrich content

---
 SPL Exam Questions EN/80 - Principles of Flight.md |    8 ++++++--
 1 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/SPL Exam Questions EN/80 - Principles of Flight.md b/SPL Exam Questions EN/80 - Principles of Flight.md
index 7b1c6f0..9ab3a41 100644
--- a/SPL Exam Questions EN/80 - Principles of Flight.md
+++ b/SPL Exam Questions EN/80 - Principles of Flight.md
@@ -1702,11 +1702,15 @@
 
 #### Answer
 
-D)
+B)
 
 #### Explanation
 
-The aerodynamic center is the point of application of the resultant of aerodynamic forces on a profile. It is distinct from the center of pressure (which moves) and the center of gravity.
+The aerodynamic centre (or centre of pressure) is the point where the resultant of all aerodynamic pressure forces (lift + drag) acts on the aerofoil. It lies on the chord line, typically near the quarter-chord point (~25% of chord from the leading edge).
+
+- **A (weight)** acts at the centre of gravity, not the aerodynamic centre.
+- **C (tyre pressure)** is irrelevant to aerodynamics.
+- **D (airflow at the leading edge)** describes the stagnation point, not the aerodynamic centre.
 
 ### Q84: Pressures are expressed in: ^t80q84
 

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