2022-11 · NASA ASRS report 1951723
C172 flight instructor and student reported flying towards terrain while entering the traffic pattern during night VMC conditions.
My student (private pilot) and I were descending from our prescribed FOM procedures for a landing back for Runway XX at ZZZ. Our procedures state that we must execute a right descending turn from 2500 ft. MSL to 2000 ft. MSL (originally heading 180 degrees to a 45 degree entry to enter the traffic pattern for Runway XX). As we were on the 45 degree entry descending down to 2000 ft. MSL; I (the instructor) was worried about traffic that was departing the pattern. Not only was the traffic a concern; it was also night (visually seeing the traffic was a little challenging). As my student was flying the plane and I was looking to see what the traffic was planning to do; I also had my eyes set for the runway. I kept glancing at my student's altitude and I noticed we were still descending (past from 2000 ft. MSL). I verbally said 'watch your altitude' to my student in hopes that we would maintain 2000 ft. MSL; however; this was not the case. We continued a descent and I kept verbalizing to 'watch your altitude.' (I was still scanning for traffic and determining our relative position). It was not until we were at 1637 ft. MSL until I took the yoke to initiate the climb again. After the climb; we entered the traffic pattern safely and landed back to ZZZ without injury. As we were taxing back to the ramp; I was concerned about the event and had FAR 91.119 (Minimum Safe Altitudes) in the back of my mind. Later that night; I filed a safety report through our school's safety reporting system and requested that my student also send one in. Our safety manager at the school provided both of us (instructor and student) data on the flight itself. Our lowest altitude that we descended down to was 1637.1 ft. MSL while the descent lasted for 23 seconds. Though the descent was not acceptable per our school procedures nor by the FARs; I brought up the 'black hole illusion' to my student and included it in the original safety report. I brought this up because I believe that this illusion had a factor in the delay in altitude recovery. Because our 45 degree to downwind for Runway XX is primarily over all trees; it was all dark where we had no close sense to what our altitude was just by looking outside the aircraft. This was because it was very dark outside. The data also showed that our FPM was originally ~800 fpm which eventually increased to ~1250 fpm. This was speculated from the safety report that he might have pushed the yoke forward to scan for traffic after leaning forward (which the student stated they did). I do feel that the 'black hole illusion' was a major factor; but with the addition to radio calls; traffic scanning; night VFR flying; and position finding all contributed to the descent. Concern was for violating 91.119 (Minimum Safe Altitudes). Our safety manager stated that the trees we were over were estimated to be at ~488 ft. meaning we were only ~438 ft. above the tree tops which is lower than the 500 ft. minimum. Our safety manager briefed myself on the report and I briefed my student on the situation and why it is also important to not only look out for traffic; but also be scanning your instruments. I briefed my student on 91.119 and how it pertains to us and my student and I looked at our flight path and saw how low we ended up going. I required my student to also file a report as well. In conclusion; night VFR flying needs to be treated heavier on emphasis in regards to scanning your instruments. Night flying will add additional errors / illusions that maybe the instructor might not be entirely familiar with; but also for the student. There is also no excuse for an instructor (like myself) to oversee how low we both got. This was a learning experience for both myself and my student and heavier situational awareness will have to be acquired for future flights.
My instructor and I were coming back on the XX corridor; passing the grain elevator and descending after passing the highway. During the descending S turn over the red barn there was departing traffic. While descending to 2;000 ft.; I was looking at the traffic; leaned forward to see where they were at and continued my descent past 2;000. When I realized the traffic was not a factor I was at 1637.1 ft. This a problem due to we were already at a low altitude being in the corridor and I descending way below 2;000 ft. This is very important to never do again because of the main safety issue being altitude. It was also dark out and it is even more important to be aware of my current surroundings. A way to correct and fix this to make sure this does not happen ever again is to properly scan my instruments; especially my altimeter to make sure I do not descend past 2;000 ft. It was dark out and with night illusions being a very serious issue; we were over a dark area.With a dark area with not many lights; there is a night illusion called the black hole illusion. That is what is especially important to keep an eye on your altimeter to make sure you do not get disoriented when flying.
Reporter no additional information to share.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.
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