Yes, a plane can land in the rain but a captain has to consider many factors before doing so. Most important of all, he must ensure that the rain does not adversely affect the visibility during the landing, the crosswind is within the limits and the braking action on the runway is at least suitable. If not, he must discontinue with the approach and divert to the alternate airport.
Generally, moderate rain does not have nearly as much impact on the visibility of the plane than as fog or snow do. The only real danger to flying in heavy rain is the fact that rain can be associated with severe weather.
Heavy rain has contributed to some accidents. The most recent major one was in July 2007. It involved a TAM Airlines Airbus A320 that crashed and burst into flames at one of Brazil’s busiest airport, killing at least 200 people. The plane skidded off the runway on landing during heavy rain, shot across a busy highway and crashed into several buildings.
On August 2005, an Air France Airbus A340 overran the runway at Toronto in heavy rain. The aircraft was destroyed in a post-accident fire. Miraculously, there were no casualties.
On September 23, 1999, a Qantas Airlines Boeing 747-400 jumbo jet arriving at Bangkok, Thailand after a flight from Sydney, Australia, ran off the runway while landing in heavy rain. All the passengers were safe.
All the accidents mentioned above took place whilst landing in rain. Of course, any crosswinds (where the surface wind blows from the side) would aggravate the landing further.
This combination of rain and crosswind is most dangerous during a landing or even on a take off. I remember an incident some years back in Shanghai where I refused to take off on a Boeing 777 because of this. It attracted a very amusing remark that was relayed to me. An irate passenger on my flight said, “How come that expat Boeing 777 pilot was able to take off whilst this (chicken) Asian pilot could not?”
Here is an extract of my previous article…
“Well, the very next day, we were caught by Typhoon Matsa whilst about to depart Shanghai. According to the forecast, the typhoon was heading towards the South Eastern part of the city. Thinking that the strong crosswind, gusting to 46 knots, would subside, we waited a little longer by delaying the departure. Instead, the wind continued to increase in intensity. In the end, I made up my mind (after conferring with my co-pilot) that we would not proceed as the force of the rain and cross wind had exceeded the limitations of the aircraft.
Interestingly, another Boeing 777 from a different airline, which was parked next to us left the departure gate and took off. This, of course angered the passengers who had been stranded at the lounge for several hours during the long delay. How could a similar plane take off whereas we could not?
It took me some pain to explain to my manager who appeared unconvinced until we found out over the radio that a United Airlines Boeing 747 and a Virgin Atlantic Airbus A340 had meekly returned after aborting their departures. I felt a sense of satisfaction to have had my hunch paid off as I felt strongly about the safety of my passengers. As such, we only departed 24 hours later when Typhoon Matsa had left Shanghai”
Furthermore, a wet and contaminated runway do pose further problems to a landing aircraft due to aquaplaning (or hydroplaning). Aquaplaning may reduce the effectiveness of wheel braking in aircraft on landing when it can cause it to run off the end of the runway. It is a condition that can exist when an aircraft is landed on a runway surface that is contaminated with water, slush or wet snow. It can have serious adverse effects on ground controllability as well as the braking efficiency.
How are planes tested to ensure they are able to land on wet runways?
Look at the video on how they tested the Airbus A380 as regards to aquaplaning plus another bonus video on how this plane was pushed to the limit and beyond to earn joint type certification from EASA and FAA in December 2006.
If you like what you read, more stories are found in my book LIFE IN THE SKIES (Preview here) and you can purchase a copy here. To check for any latest updates or postings, you can follow my Twitter at @CaptKHLim or Facebook here