Destructive Detonation
Know the symptoms, and act fast!
BY MIKE BUSCH
AT LEAST ONCE A year I am contacted by an aircraft owner whose piston aircraft engine was destroyed or severely damaged by a
destructive detonation or pre-ignition event. Lately, the pace seems
to be quickening; in a recent 12-month period, I’ve encountered
three of them.
One incident involved a Cirrus SR20 powered by a 200-hp
Teledyne Continental Motors (TCM) IO-360-ES engine. The plane
was equipped with a snazzy Avidyne Entegra multi-function display
(MFD) with an integrated engine monitoring system called EMax.
Everything looked fine until about two minutes after the pilot
applied takeoff power, at which point the cylinder head temperature
(CHT) of the No. 1 cylinder began to climb
rapidly compared to the other five cylinders.
At the three-minute mark—with the aircraft
at roughly 2,000 feet above ground level—
No. 1’s CHT rose above 400°F and set off a
high-CHT alarm on the MFD.
Number one cylinder head
and piston destroyed.
?
Avidyne MFD does not
display CH Ts above 500˚F
CHT1
CHT2
CHT3
CHT4
CHT5
CHT6
500
480
460
440
420
400
380
360
340
320
300
280
260
240
220
Thermal runaway
CH T#1 Alarm
Throttle-up to takeoff power
About 2 min!
10: 29
10: 39
10: 49
The cylinder head temperature (CH T) data
downloaded from the EMax system tells the short
tale of the TCM IO-360-ES engine’s demise.
