The Density Altitude<\/strong> describes the altitude at which an aircraft \"feels\" it is operating due to the current air density - regardless of the actual altitude. It is a Relevant power factor<\/strong>which results from the pressure altitude, temperature and humidity. The warmer, the thinner the air - the higher the Density Altitude.<\/p>\n\n\n\n Example: An aerodrome in Switzerland at 1400 feet MSL can behave on a hot summer day with 32 \u00b0C and QNH 1013 hPa like 4500 feet<\/strong> or more \"feel\". This means that the aircraft behaves in terms of performance as if it were taking off from a high mountain airfield - with all the consequences.<\/p>\n\n\n\n 1. reduced engine power<\/strong> 2. longer starting distance<\/strong> 3. higher true airspeed with the same IAS<\/strong> 4. longer landing distance<\/strong> 5. limited tax effect<\/strong> With its valleys, high plateaus and thermally active slopes, Switzerland is regarded as a Complex flying area<\/strong>. When high temperatures are added to the mix, the density altitudes often rise to over 6000 feet - even on places like Zweisimmen<\/strong>, Grenchen<\/strong> or Locarno<\/strong>. Climbing performance of only 300 ft\/min at MTOW<\/strong> are not uncommon.<\/p>\n\n\n\n This topic is therefore regularly covered during familiarisation flights in the Alps - but even experienced pilots should never underestimate the effects of the summer heat.<\/p>\n\n\n\n If you would like to delve deeper into the subject, you will find valuable information in the following articles and sources:<\/p>\n\n\n\n High temperatures are not an exception, but have long been part of the flying season in Central Europe. The Density Altitude<\/strong> is one of the most important factors influencing safety - it affects performance, controllability, route requirements and decision-making behaviour. Whoever integrated into flight planning at an early stage<\/strong>who prepares for scenarios and acts consciously will fly safely even in midsummer.<\/p>\n\n\n\n
\n\n\n\nEffects on engine, lift and controls<\/h3>\n\n\n\n
Piston engines deliver less power in hot, thin air. Turbo engines and turboprops are also affected, albeit less dramatically. The propeller has less \"bite\", which prolongs acceleration and reduces the rate of climb.<\/p>\n\n\n\n
As less thrust and lift are generated, the rolling distance is significantly longer. This can be further exacerbated on grass tracks or damp surfaces.<\/p>\n\n\n\n
The IAS (Indicated Airspeed) remains the same, but the actual speed over ground (TAS) is higher in thin air. This means more kinetic energy - both during take-off and landing.<\/p>\n\n\n\n
The higher approach TAS not only increases the touchdown point, but also extends the braking distance. In addition, the braking effect of the air (aerodynamically) is reduced. This is particularly critical on short or high-altitude runways such as Samedan (LSZS), Courchevel or Zell am See<\/strong>.<\/p>\n\n\n\n
Control surfaces (elevator, rudder, ailerons) lose effectiveness at low air density. This can lead to delayed or less precise reactions, especially when touching down or during go-around.<\/p>\n\n\n\n
\n\n\n\nTypical mistakes - and how to avoid them<\/h3>\n\n\n\n
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\n\n\n\nRecommendations for flight preparation<\/h3>\n\n\n\n
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\n\n\n\nSpecial attention in the Alps<\/h3>\n\n\n\n
\n\n\n\nFurther reading & links<\/h3>\n\n\n\n
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\n\n\n\nConclusion: summer flights need a cool head<\/h3>\n\n\n\n