When asking our quality manager Hartmut Schneider, which kind of projects are the most spectacular ones in his opinion, he’d answer: airport projects. In the following he reports on the general challenges during runway sensor acceptance tests…
On large international airports, it can take several years until an installation and acceptance of embedded road sensors such as the IRS31Pro- and the ARS31Pro-UMB is completed. There, it’s much more complicated than on motorways or other roads. This is owed to the high safety demands as well as the high traffic frequency, which need to be redirected during jobs on the tarmac.
The Lufft surface sensors are mostly installed at several measurement spots in form of sensor couples, since the passive IRS31Pro and the active ARS31Pro road sensor complement each other. Whereas the IRS31Pro delivers information on road surface temperature, water film height, friction, ice percentage as well as freezing points of certain de-icing materials (salt), the ARS31Pro detects freezing points indepently from the used de-icing chemicals by means of a Peltier element.
Right after installation, we carry out a first functionality test of the sensor e.g. for the temperature detection by using a reference measurement device, such as the highly accurate Lufft XP101 hand held device in combination with a PT100 surface temperature probe. Later on, another testing is necessary for the sensors’ final acceptance. In some cases, these two tests are separated by years.
When carrying out such final comparison measurements, the road sensor shouldn’t exceed differences of 0.3 °C compared to the reference device. For this procedure, a special paste ensures a better thermal coupling of the temperature sensor and the inspected surface.
After a three-minute acclimation, the embedded road sensors used to be within the required accuracy and deviated only about 0.17 °C in average. Sometimes, the difference was even less than 0.07 °C. This confirms the excellent road sensors’ performance.
Comparison measurements on airports require a precise planning, registration, as well as the runway blocking which is almost never possible during daytime, in which aircrafts start and land every few minutes. For the work on the sensors during the day, you often just get a few minutes until the tower asks you to leave the runway again.
At night, there are quieter and more favorable periods for the sensor tests on runways. The flight take offs and landings can be diverted to one runway during this time while the other one is decommissioned. A typical time for starting night shifts on airport tarmacs is 1 a.m.
Before accessing the concerned taxiways, we (one airport employee, a technician and me) as well as our whole equipment need to get through the security gate. After finishing the job on the first runway, the second follows in the same manner (blocking, redirecting the traffic and performing the reference measurements) causing a high organizational effort.
After such night shifts we are often rewarded with a beautiful sunrise.